全文获取类型
收费全文 | 101篇 |
免费 | 4篇 |
国内免费 | 2篇 |
专业分类
测绘学 | 2篇 |
大气科学 | 3篇 |
地球物理 | 30篇 |
地质学 | 29篇 |
海洋学 | 15篇 |
天文学 | 18篇 |
综合类 | 1篇 |
自然地理 | 9篇 |
出版年
2022年 | 1篇 |
2021年 | 5篇 |
2020年 | 2篇 |
2018年 | 3篇 |
2017年 | 5篇 |
2016年 | 4篇 |
2015年 | 1篇 |
2014年 | 4篇 |
2013年 | 6篇 |
2012年 | 1篇 |
2011年 | 7篇 |
2010年 | 3篇 |
2009年 | 9篇 |
2008年 | 2篇 |
2007年 | 6篇 |
2006年 | 4篇 |
2005年 | 3篇 |
2004年 | 5篇 |
2003年 | 2篇 |
2002年 | 1篇 |
2001年 | 1篇 |
2000年 | 2篇 |
1999年 | 1篇 |
1998年 | 1篇 |
1996年 | 1篇 |
1994年 | 2篇 |
1993年 | 2篇 |
1992年 | 2篇 |
1990年 | 1篇 |
1989年 | 3篇 |
1986年 | 1篇 |
1984年 | 2篇 |
1983年 | 3篇 |
1982年 | 2篇 |
1976年 | 3篇 |
1972年 | 2篇 |
1971年 | 3篇 |
1969年 | 1篇 |
排序方式: 共有107条查询结果,搜索用时 31 毫秒
71.
Takeyasu Sawa Tatsuya Kurita Akira Sobue Yutaka Sabano 《Astrophysics and Space Science》1983,92(1):181-190
The CO distribution in the Galaxy is investigated through an analysis of longitude-velocity diagrams of CO emission lines for the two longitude ranges 20°<l<80° and 105°<l<140°. For the kinematics of the Galaxy we adopt the three typical models; the circular rotation, the linear density waves, and the galactic shock waves. It is shown that the distributions and kinematics of CO clouds are consistent with the predictions of the density wave model and the galactic shock model, and that the observed data of CO emissions do not contradict with the claim that the CO clouds form spiral arms. 相似文献
72.
S. Tsuneta T. Takakura N. Nitta K. Ohki K. Makishima T. Murakami M. Oda Y. Ogawara 《Solar physics》1983,86(1-2):313-321
This paper presents studies of the vertical structure of hard X-ray flares for two contrasting examples. The 1981 May 13 flare contained a coronal hard X-ray source which was located above 50000 km above the photosphere. On the other hand, the 1981 July 20 flare had a chromospheric double source structure in the initial phase. Electrons in this case were able to stream freely from the corona to the chromosphere. 相似文献
73.
Quantifying aggregation and change in runoff source in accordance with catchment area increase in a forested headwater catchment 下载免费PDF全文
There has been a great deal of research interest regarding changes in flow path/runoff source with increases in catchment area. However, there have been very few quantitative studies taking subscale variability and convergence of flow path/runoff source into account, especially in relation to headwater catchments. This study was performed to elucidate how the contributions and discharge rates of subsurface water (water in the soil layer) and groundwater (water in fractured bedrock) aggregate and change with catchment area increase, and to elucidate whether the spatial variability of the discharge rate of groundwater determines the spatial variability of stream discharge or groundwater contribution. The study area was a 5‐km2 forested headwater catchment in Japan. We measured stream discharge at 113 points and water chemistry at 159 points under base flow conditions. End‐member mixing analysis was used to separate stream water into subsurface water and groundwater. The contributions of both subsurface water and groundwater had large variability below 1 km2. The contribution of subsurface water decreased markedly, while that of groundwater increased markedly, with increases in catchment area. The specific discharge of subsurface water showed a large degree of variability and decreased with catchment area below 0.1 km2, becoming almost constant above 0.1 km2. The specific discharge of groundwater showed large variability below 1 km2 and increased with catchment area. These results indicated that the variabilities of stream discharge and groundwater contribution corresponded well with the variability of the discharge rate of groundwater. However, below 0.1 km2, it was necessary to consider variations in the discharge rates of both subsurface water and groundwater. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
74.
Malarvannan G Takahashi S Ikemoto T Isobe T Kunisue T Sudaryanto A Miyagi T Nakamura M Yasumura S Tanabe S 《Marine pollution bulletin》2011,63(5-12):541-547
Two species of fishes (n=52; tilapia and mullet) from industrialized and urbanized areas of Okinawa Island (Manko-Noha river, Hija river and Shikaza river) and from a remote area of Ishigaki Island (Anparu mudflat), Japan were collected between August 2005 and July 2006, and analyzed for five organochlorine compounds (OCs), viz., DDTs, PCBs, CHLs, HCHs and HCB. Concentrations and the contamination patterns of OCs in fishes varied between locations. Considerable residue levels of OCs, especially CHLs and DDTs were found in both fishes from the main Okinawa Island. These levels were relatively higher than the reported values for seafood from Japanese coasts, indicating that even now pollution sources of these contaminants still exist in this region. On the other hand, lower concentrations of OCs were detected in fishes from Ishigaki Island waters than those of other Japanese coastal waters, suggesting that this region is less contaminated by OC contaminants. 相似文献
75.
Narumi Takahashi Yasuhisa Ishihara Hiroshi Ochi Tatsuya Fukuda Jun’ichiro Tahara Yosaku Maeda Motoyuki Kido Yusaku Ohta Katsuhiko Mutoh Gosei Hashimoto Satoshi Kogure Yoshiyuki Kaneda 《Marine Geophysical Researches》2014,35(3):243-253
We have developed a new system for real-time observation of tsunamis and crustal deformation using a seafloor pressure sensor, an array of seafloor transponders and a Precise Point Positioning (PPP ) system on a buoy. The seafloor pressure sensor and the PPP system detect tsunamis, and the pressure sensor and the transponder array measure crustal deformation. The system is designed to be capable of detecting tsunami and vertical crustal deformation of ±8 m with a resolution of less than 5 mm. A noteworthy innovation in our system is its resistance to disturbance by strong ocean currents. Seismogenic zones near Japan lie in areas of strong currents like the Kuroshio, which reaches speeds of approximately 5.5 kt (2.8 m/s) around the Nankai Trough. Our techniques include slack mooring and new acoustic transmission methods using double pulses for sending tsunami data. The slack ratio can be specified for the environment of the deployment location. We can adjust slack ratios, rope lengths, anchor weights and buoy sizes to control the ability of the buoy system to maintain freeboard. The measured pressure data is converted to time difference of a double pulse and this simple method is effective to save battery to transmit data. The time difference of the double pulse has error due to move of the buoy and fluctuation of the seawater environment. We set a wire-end station 1,000 m beneath the buoy to minimize the error. The crustal deformation data is measured by acoustic ranging between the buoy and six transponders on the seafloor. All pressure and crustal deformation data are sent to land station in real-time using iridium communication. 相似文献
76.
The intensity of the diffuse component of cosmic X-rays was measured with use of a rotating collimator system borne on a sounding rocket. A part of background counts proportional to the field of view of proportional counters enabled us to determine the intensity of the diffuse component to be 0.66±0.07 photons cm–2 sec–1 keV–1 in the energy range between 3.6 and 9.0 keV. The spectrum in this energy range was found to be comparatively flat. The intensity of Sco X-1 was also measured and its time variation was investigated. 相似文献
77.
Takahiro Watanabe Toshio Nakamura Fumiko Watanabe Nara Takeshi Kakegawa Kazuho Horiuchi Ryoko Senda Takefumi Oda Mitsugu Nishimura Genki Inoue Matsumoto Takayoshi Kawai 《Quaternary International》2009,205(1-2):12
High-time resolution 14C dating of Lake Baikal sediment cores indicates negative and positive anomalies of calculated linear sedimentation rate (LSR; 1.1 and 35.6 cm/ka, respectively) during the period of climate transition from the last glacial to Holocene. The timing of the Lake Baikal apparent LSR anomalies is consistent with that of the changes in the atmospheric radiocarbon concentration (Δ14C) during Younger Dryas rapid cooling event. 14C dating of lipids in the Lake Baikal surface sediments revealed that the sources of sedimentary lipids were different in each basin. In the Northern Basin of Lake Baikal, the 14C age of total lipids from the surface sediment (4.0 14C ka) was found to be older than that of TOC (1.6 14C ka). By contrast, the 14C age of total lipids in the Southern Basin was younger than that of the TOC by ca. 0.7–3.0 ka.In the Lake Hovsgol sediment cores, ages of the main lithologic boundaries during the last glacial–interglacial transition were estimated based on new 14C data sets. TOC concentration in the cores started to rapidly increase at 13.8 ± 0.3 14C ka at the base of the basinwide finely laminated layer deposited during Bølling/Allerød. The base of the layer diatomaceous mud corresponds to the end of Younger Dryas event (10.6 ± 0.1 14C ka). 相似文献
78.
Kazue Tazaki Ryuji Asada Zara Gerhardt Lindenmayer Tatsuya Shirotori Juliana Missiaggia Vargas Carlos Henrique Nowatzki Osmar Wöhl Coelho 《International Journal of Earth Sciences》2009,98(1):227-238
Rock erosion is attracting increasing attention from scientists worldwide. The area encompassing the Saint John Baptist Church,
Saint John Village, XVII century ruins in Rio Grande do Sul at the UNESCO World Heritage Site is considered a Brazilian treasure.
However, the risk of damage to this site from rock erosion has recently increased tremendously. Generally, the rocky construction
such as fence, wall and tomb stone, seems strong but is actually extremely sensitive to erosion caused by lichens, fungi,
molds and bacteria. Because of biological erosion and massive exposure, the fresh rock is dominated by clays and microorganisms.
Water-adsorbing clays and microorganisms influence the mechanisms of the rock erosion. In this study, the formation of bio-clay-minerals
in porous structure of pisolite was demonstrated using electron microscopy. Bacterial clay mineralization can deform the rock
structure and even produce organic materials. Biological activity could easily corrode rocky constructions around the Saint
John Baptist Church site. The rocks are pisolitic laterites possibly formed in Tertiary over the Kretaceous Parana flood Basalts.
Samples inhabited by lichens and fungi were collected from a collapsed wall in the ancient church. The zonal reddish-brown
pisolites are 4 mm in diameter in a matrix of clays associated with porous and empty spaces. Elemental distribution maps from
X-ray fluorescence microscopy show iron-rich spherules of pisolite, whereas the matrix is composed of Al, Si, Mn, and Sr;
thus producing goethite and kaolinite. Transmission electron microscopic observation showed that various types of bacteria
inhabit the spherule and are associated with clay minerals and graphite. STEM elemental analysis confirmed the bio-clay-mineralization
with Al, Si, S, and Fe, around bacterial cells. The results presented here will improve our understanding of nm-scale bio-mineralization
and bio-erosion in lateritic rocks.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
79.
Masami Izuho Yuichi Nakazawa Fumito Akai Tsutomu Soda Hirotaka Oda 《Geoarchaeology》2009,24(4):492-517
In order to better understand modern human behavioral variability in Hokkaido, Japan, we consider the geoarchaeology of the Kamihoronai‐Moi site in terms of its geochronology, stratigraphy, depositional environments, and post‐depositional disturbances. A Paleolithic component is stratigraphically situated between the Eniwa‐a (15,000–17,000 14C yr B.P.) and the Tarumae‐d (8000–9000 14C yr B.P.) tephras. Moreover, six AMS 14C ages on charcoal from a Pleistocene‐aged hearth feature are between 14,400 and 14,800 14C yr B.P. Quantitative examinations of patterns in artifact distributions show a low degree of vertical and horizontal displacement of chipped‐stone artifacts, suggesting that post‐depositional movement of the cultural material was insufficient to disrupt the original pattern of artifact distribution. © 2009 Wiley Periodicals, Inc. 相似文献
80.
Y. Ogawara M. Matsuoka S. Miyamoto N. Muranaka J. Nishimura M. Oda 《Astrophysics and Space Science》1976,42(1):211-216
In the record of the balloon observation which was performed on 27 September, 1970, a transient burst of X-rays was found. This event is concluded to be a cosmic gamma-ray burst of a smaller size or of a larger distance compared to the Vela bursts observed over the X-ray energy range. The energy spectrum is consistent with that of some of the Vela bursts. The time profile of the event is qualitatively similar to the 27 April, 1972 event studied by Apollo 16. The detection of small bursts over the X-ray energy range by the balloon observation during a period of the order of 10 to 100 h is not surprising considering a probable frequency-size distribution of the burst.Paper presented at the COSPAR Symposium on Fast Transients in X- and Gamma-Rays, held at Varna, Bulgaria, 29–31 May, 1975. 相似文献