全文获取类型
收费全文 | 178篇 |
免费 | 10篇 |
国内免费 | 3篇 |
专业分类
大气科学 | 19篇 |
地球物理 | 48篇 |
地质学 | 52篇 |
海洋学 | 45篇 |
天文学 | 18篇 |
综合类 | 1篇 |
自然地理 | 8篇 |
出版年
2021年 | 3篇 |
2020年 | 2篇 |
2019年 | 1篇 |
2018年 | 4篇 |
2017年 | 5篇 |
2016年 | 7篇 |
2015年 | 1篇 |
2014年 | 10篇 |
2013年 | 8篇 |
2012年 | 2篇 |
2011年 | 4篇 |
2010年 | 11篇 |
2009年 | 5篇 |
2008年 | 5篇 |
2007年 | 9篇 |
2006年 | 6篇 |
2005年 | 5篇 |
2004年 | 4篇 |
2003年 | 6篇 |
2002年 | 11篇 |
2001年 | 8篇 |
2000年 | 7篇 |
1999年 | 4篇 |
1998年 | 3篇 |
1997年 | 1篇 |
1996年 | 3篇 |
1995年 | 2篇 |
1994年 | 4篇 |
1993年 | 5篇 |
1992年 | 2篇 |
1991年 | 1篇 |
1990年 | 2篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1986年 | 5篇 |
1985年 | 5篇 |
1984年 | 3篇 |
1983年 | 1篇 |
1982年 | 4篇 |
1981年 | 2篇 |
1980年 | 2篇 |
1979年 | 4篇 |
1978年 | 4篇 |
1977年 | 3篇 |
1974年 | 3篇 |
1973年 | 1篇 |
1970年 | 1篇 |
排序方式: 共有191条查询结果,搜索用时 734 毫秒
101.
A study is made on the surface distribution ofTrichodesmium thiebautii Gomont in the East China Sea during the years 1961–1967.
- This alga is very scarce or absent in the period from January to March, and begins to increase in May and June, reaching the maximum population density from July to September, and again decreases in October and November.
- In summerT. thiebautii is predominantly distributed in the area along the Kuroshio current with high densities of 102–103 filaments/l, occasionally exceeding 103 filaments/l. This alga is estimated to occupy the major part or almost all the parts of chlorophylla in situ contained in the surface water of this season.
- The occurrence ofT. thiebautii off the southern coasts of Central Japan seems to be caused rather by the multiplication in its own habitat than by the transportation by the Kuroshio current from the East China Sea.
102.
Osamu Ishizuka 《Resource Geology》2008,58(3):206-219
In the Izu–Bonin Arc, hydrothermal activities have been reported from volcanoes along present‐day volcanic front, a rear arc volcano and a back‐arc rift basin as well as a remnant arc structure now isolated from the Quaternary arc. It is widely known that characteristics of hydrothermal activity (mineralogy, chemistry of fluid etc.) vary depending upon its tectonic setting. The Izu–Bonin Arc has experienced repeated back‐arc or intra‐arc rifting and spreading and resumption of arc volcanism. These characteristics make this arc system a suitable place to study the tectonic control on hydrothermal activity. The purpose of the present paper is, therefore, to summarize volcanotectonic setting and history of the Izu–Bonin Arc in relation to the hydrothermal activity. The volcanotectonic history of the Izu–Bonin Arc can be divided into five stages: (i) first arc volcanism (boninite, high‐Mg andesite), 48–46 Ma; (ii) second arc volcanism (tholeiitic, calc‐alkaline), 44–29 Ma; (iii) first spreading of back‐arc basin (Shikoku Basin), 25–15 Ma; (iv) third arc volcanism (tholeiitic, calc‐alkaline), 13–3 Ma; and (v) rifting in the back‐arc and tholeiitic volcanism along the volcanic front, 3–0 Ma. Magmas erupted in each stage of arc evolution show different chemical characteristics from each other, mainly due to the change in composition of slab‐derived component and possibly mantle depletion caused by melt extraction during back‐arc spreading and prolonged arc volcanism. In the volcanotectonic context summarized here, hydrothermal activity recognized in the Izu–Bonin Arc can be classified into four groups: (i) present‐day hydrothermal activity at the volcanic front; (ii) active hydrothermal activity in the back arc; (iii) fossil hydrothermal activity in the back‐arc volcanoes; and (iv) fossil hydrothermal activity in the remnant arc. Currently hydrothermal activities occur in three different settings: submarine caldera and stratocones along the volcanic front; a back‐arc rift basin; and a rear arc caldera. In contrast, hydrothermal activities found in the back‐arc seamount chains were associated with rear arc volcanism in Neogene after cessation of back‐arc spreading of the Shikoku Basin. Finally, sulfide mineralization associated with boninitic volcanism in the Eocene presumably took place during forearc spreading in the initial stage of the arc. This type of activity appears to be limited during this stage of arc evolution. 相似文献
103.
Ken Furuya Osamu Hasegawa Takashi Yoshikawa Satoru Taguchi 《Journal of Oceanography》1998,54(5):545-552
The light-saturated maximum value (P
B
max) and initial slope (α) of the photosynthesis-irradiance (P-E) curve were examined in a warm streamer, a cold streamer and
a warm core ring off the Sanriku area in the subarctic western North Pacific Ocean during an ADEOS/OCTS Sanriku field campaign
in early May 1997. BothP
B
max and α were within the ranges of temperate populations. A regional difference was apparent inP
B
max: populations in the warm streamer tended to show higher value ranging between 1.92 and 4.74 mgC (mgChla)−1h−1 than those in the cold streamer and the warm core ring (1.35–2.87 mgC (mgChla)−1h−1). A depth variation was also observed in α in both the warm streamer and the warm core ring: shallow populations tended to
have lower α than deep populations. The depth variations in bothP
B
max and α resulted in a lower light intensity of the light saturation in a deeper population than that of a shallower one. These
depth-related variations in the P-E parameters were likely a manifestation of “shade-adaptation” of photosynthesis. Photoinhibition
was not observed over in situ surface light intensity varying below ca 1600 μmol photon m−2s−1. Water-column primary productivity was biooptically estimated to be 233 to 949 mgC m−2d−1 using vertical distributions of the P-E parameters, chlorophylla, phytoplankton light absorption and underwater irradiance. Applicability of surface data sets for estimation of water-column
productivity is discussed. 相似文献
104.
Yamamoto T Goto I Kawaguchi O Minagawa K Ariyoshi E Matsuda O 《Marine pollution bulletin》2008,57(1-5):108-115
We examined whether replantation of benthic microalgae (BMA) can remediate shallow organically enriched sediment. Nitzschia sp., the dominant species in the tested area (Hiroshima Bay, Japan), was isolated and mass cultured, then replanted in the same area. Changes in the condition of the sediment were monitored for five months. During the study period, we observed an increase in redox potential (ORP) and a decrease in acid-volatile sulfide (AVS) in the experimental area, indicating that the sediment condition changed from reduced to oxic. Organic matter in the sediment, represented by chemical oxygen demand (COD), ignition loss (IL) and organic nitrogen (ON) decreased significantly, while inorganic nutrients (ammonia and phosphate) increased in the interstitial water. These changes imply that oxygen produced by the replanted BMA may have enhanced aerobic bacterial activity, accelerating the decomposition of organic matter. Thus, replantation of BMA shows potential as a novel and promising "phytoremediation" method for organically enriched sediment. 相似文献
105.
Tamiji Yamamoto Toshiya Hashimoto Hidetaka Takeoka Tenji Sugiyama Osamu Matsuda 《Journal of Oceanography》2000,56(2):131-139
Field observations were conducted to examine the processes governing the phytoplankton distribution and photosynthetic activity in and around a tidal front formed in Iyo Nada, the Seto Inland Sea, Japan. The existence of a middle layer intrusion, which, it has been suggested, moves from the mixed region to the stratified region of the tidal front, was ascertained by the phytoplankton distribution in addition to a T-S diagram. Skeletonema costatum, which originally inhabited the mixed region, was used as the indicator to reveal the intrusion. However, the tip of water containing the S. costatum population did not extend deeply into the stratified region. The velocity of the intrusion seemed to be slow enough to make biological processes, such as nutrient uptake by phytoplankton and subsequent growth, as well as the decrease in cell density due to zooplankton grazing, dominate during the transportation. The patchy distribution of copepod nauplii implied that grazing has an influence on the distribution pattern of phytoplankton. The location of high photosynthetic activity did not coincide spatially with the center of high phytoplankton biomass, suggesting the importance of these biological processes. Therefore, it is considered that the middle layer intrusion plays a role as an inducer of subsequent biological processes at the tidal front by not only supplying nutrients from the mixed region but also by increasing the vertical diffusivity. 相似文献
106.
Putth Songsangjinda Osamu Matsuda Tamiji Yamamoto Narasimmalu Rajendran Hajime Maeda 《Journal of Oceanography》2000,56(2):223-231
The predominance of bivalves affects the cycle of materials in the coastal ecosystem. In the present study, the role of suspended oyster culture on the nitrogen cycle was demonstrated for the northern Hiroshima Bay. The nitrogen cycle was considered as two systems, (1) the primary production (PP) system and (2) the oyster culture (OC) system. The results show that about 26% of N productivity was supplied to process by cultured oysters in the OC system. This process varies seasonally due to the seasonal variations of PON, physiological activities and biomass of oysters. The N processing rates were found to be high in summer and low in winter. The biodeposition and excretion of N in the OC system are 3.0 and 2.1 ton N d–1, while the natural sedimentation rate and N regeneration in the PP system are 8.3 and 18.0 ton N d–1, which indicates that the PP system is a major system regenerating N in the water column. The release of total dissolved N from the bottom to the water column is about 8.3 ton N d–1. The amount of N harvested as oyster product was about 1.3 ton N d–1, which is about 10% of daily N loading in north Hiroshima Bay. According to the N cycle developed in the present study, the results suggest the significant role of suspended oyster culture on the nitrogen cycle in Hiroshima Bay. In addition, our results indicate that oyster production was efficiently harvested, suggesting that oyster culture could probably be used as a tool to remove N from Hiroshima Bay. 相似文献
107.
Tatsuro Watanabe Daisuke Simizu Kou Nishiuchi Toru Hasegawa Osamu Katoh 《Journal of Oceanography》2009,65(6):791-801
We examined the surface current structure in the Tsushima Warm Current (TWC) region of the Japan Sea based on a dataset from
satellite-tracked surface drifters, including our new deployments during 2004–2008. The gridded mean current velocity and
mean kinetic energy (KE) fields calculated from all available drifter data revealed the structure and seasonality of the three
branches of the TWC. By comparing the eddy kinetic energy (EKE) field to the KE field, we found four regions where the ratio
of EKE to KE was high. In particular, this ratio became extremely high east of the Oki Islands located between the first branch
of the TWC (FBTWC) and the second branch of the TWC (SBTWC). Our analysis suggests that the generation of alternate warm and
cold eddies east of the Oki Island induced this high ratio. The occurrence of a warm or cold eddy was related to the route—either
nearshore or offshore—of the SBTWC. When the offshore route of the SBTWC became dominant, a warm eddy was frequently generated
east of the Oki Islands. In contrast, when the nearshore route of the SBTWC became dominant, a cold eddy was more likely to
be generated. 相似文献
108.
This paper compares the management of recreational fisheries for pink snapper (Pagrus auratus) in the inner gulfs of Shark Bay (Australia) and the closely related red sea bream (Pagrus major) in Sagami Bay (Japan). Fishing and other factors have resulted in population declines of these species in both regions. In response, fishery managers have employed contrasting management, more conventional catch controls in Shark Bay and stock enhancement in Sagami Bay. Although recreational harvest levels were higher than commercial levels in both fisheries, the driving mechanisms are comparatively different due to historical, social, economic and political issues in the respective locations. 相似文献
109.
Reina Nakaoka Soko Kado Shuichi Hasegawa Keiko Suzuki-Kamata Osamu Ishizuka Shun Sekimoto Hiroshi Kawabata Yoshiyuki Tatsumi 《Island Arc》2021,30(1):e12378
Ar-Ar ages, and petrographical and geochemical characteristics of pyroclastics and an overlying lava from Teshima Island, southwest Japan are presented. Although previous geological and age data suggested Teshima pyroclastics were products of magmatism > 3 my prior to lava flows of Setouchi volcanic rocks generated in association with southward migration of the southwest Japan arc sliver during opening of the Sea of Japan backarc basin at ~ 15 Ma, the present results led to the conclusion that a sequence of Setouchi volcanism, induced by slab melting and subsequent melt-mantle reactions, produced both pyroclastics and lava at 14.6–14.8 Ma. This age is oldest among those reported so far and may represent the timing of onset of characteristic Setouchi magmatism immediately posterior to and hence as a result of the mega-tectonic event including rotation of the southwest Japan arc sliver. 相似文献
110.
Miki S Ikeda K Oba Y Satone H Honda M Shimasaki Y Onikura N Arakawa O Oshima Y 《Marine pollution bulletin》2011,62(11):2533-2536
We investigated levels of the pollutant tributyltin (TBT) in blood of pufferfishes (six species), Japanese sea perch, red sea bream, Japanese common goby, Japanese flounder, rockfish, conger eel, and sea mullet collected off the coast of northern Kyushu, Japan. We found considerable levels of TBT (1.4-190 ng/mL) accumulated in the blood of these fish. Blood TBT concentrations were 1.3-22.5 times liver concentrations and 4.9-78 times muscle concentrations, except in conger eel and mullet. We detected TBT (16-111 ng/mL-blood) in the plasma of the fine-patterned puffer (Takifugupoecilonotus) year-round, without any apparent seasonal trend. These results suggest that fish inhabiting coastal areas of Kyushu, Japan, continue to be contaminated with TBT. 相似文献