全文获取类型
收费全文 | 174篇 |
免费 | 5篇 |
国内免费 | 2篇 |
专业分类
测绘学 | 2篇 |
大气科学 | 11篇 |
地球物理 | 55篇 |
地质学 | 57篇 |
海洋学 | 32篇 |
天文学 | 17篇 |
自然地理 | 7篇 |
出版年
2022年 | 1篇 |
2021年 | 3篇 |
2020年 | 1篇 |
2019年 | 6篇 |
2018年 | 8篇 |
2017年 | 8篇 |
2016年 | 9篇 |
2015年 | 3篇 |
2014年 | 10篇 |
2013年 | 12篇 |
2012年 | 5篇 |
2011年 | 17篇 |
2010年 | 9篇 |
2009年 | 13篇 |
2008年 | 17篇 |
2007年 | 7篇 |
2006年 | 8篇 |
2005年 | 1篇 |
2004年 | 5篇 |
2003年 | 3篇 |
2002年 | 5篇 |
2001年 | 3篇 |
2000年 | 2篇 |
1999年 | 1篇 |
1998年 | 4篇 |
1996年 | 1篇 |
1995年 | 1篇 |
1994年 | 1篇 |
1993年 | 2篇 |
1992年 | 2篇 |
1991年 | 3篇 |
1990年 | 1篇 |
1989年 | 2篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1985年 | 2篇 |
1984年 | 1篇 |
1982年 | 1篇 |
1978年 | 1篇 |
排序方式: 共有181条查询结果,搜索用时 62 毫秒
81.
The differences in quality of the conditional stability constants deduced from ligand titration and metal titration methods are theoretically examined. The ecological role of the metal-organic complexes in seawater was considered on the basis of the concept of the metal buffering capacity index which is calculated from the conditional stability constant and the organic ligand concentration. The results of theoretical examination of the effect of metal contamination on the uptake of metals by phytoplankton indicate that the ecological significance of metal-organic complexes is essentially in the metal-buffering action. This means that the activities of free metal ions are maintained at a native constant level against relatively small perturbations by the addition or uptake of metals in the marine environment. 相似文献
82.
To clarify the nature of organic metal complexes dissolved in seawater, a ligand exchange reaction between ligands of natural origin and an aminopolycarboxylic acid (EDTA) was used to determine the conditional stability constants of organic metal complexes. The results indicate that more than two organic molecules complexed with copper and zinc exist in surface seawater. It is found that the conditional stability constants of these naturally-occurring organic metal complexes are 1–3 orders of magnitude higher than those of EDTA-Cu and EDTA-Zn complexes. These estimates of the conditional stability constants for the dominant species of organic copper and zinc complexes are 1011.8 and 109.3, respectively, at pH 8.1. The results indicate that these naturally-occurring organic metal complexes are stable species and not easily dissociated or displaced with others in the marine environment. 相似文献
83.
The interaction between thorium and marine organisms (cultured heterotrophic bacteria) was experimentally examined by using chemical equilibrium techniques. Thorium (Th) quantitatively reacts with a binding site on bacteria (Alteromonas, Vibrio, Pseudomonas and Flavobacterium) in 0.1 M HCl solution. According to mass balance analysis of adsorption experiment data, Th forms a 1:1 complex with a binding site similar in reactivity among bacteria used in this study, whose conditional stability constants are in the range from 10(6.63) to 10(7.07) M-1 under the experimental conditions of a 0.1 M HCl solution. The mole ratio of the strong ligand to organic carbon in bacteria ranged from 2.3 to 4.3 mmol/mol C. The strong ligand/carbon ratios in bacteria were more than one order of magnitude greater than in phytoplankton, zooplankton or other organic ligands in surface waters. The results suggest that the strong organic ligand reacting with Th is one of the functional groups commonly existing in oceanic microorganisms. The conditional stability constants of the Th complexes with the binding site in marine microorganisms are in the same order of magnitude as that with the strong ligand found in particulate and dissolved organic matter. These findings strongly suggest that the strong ligand in particulate and dissolved organic matter, reacting with trace metals under the conditions of seawater, originates from marine organisms. 相似文献
84.
Naoki Hirose Hideyuki Kawamura Ho Jin Lee Jong-Hwan Yoon 《Journal of Oceanography》2007,63(3):467-481
This study estimates a realistic change of the Japan Sea by assimilating satellite measurements into an eddy-resolving circulation
model. Suboptimal but feasible assimilation schemes of approximate filtering and nudging play essential roles in the system.
The sequential update of error covariance significantly outperforms the asymptotic covariance in the sequential assimilation
due to the irregular sampling patterns from multiple altimeter satellites. The best estimates show an average rms difference
of only 1.2°C from the radiometer data, and also explain about half of the sea level variance measured by the altimeter observation.
The subsurface conditions associated with the mesoscale variabilities are also improved, especially in the Tsushima Warm Current
region. It is demonstrated that the forecast limit strongly depends on variable, depth, and location. 相似文献
85.
Kazufusa Ishibashi Kei Hirose Nagayoshi Sata Yasuo Ohishi 《Physics and Chemistry of Minerals》2008,35(4):197-200
The high-pressure stability limit of calcium aluminosilicate (CAS) phase has been examined in its end-member CaAl4Si2O11 composition at 18–39 GPa and 1,670–2,300 K in a laser-heated diamond-anvil cell (LHDAC). The in-situ synchrotron X-ray diffraction
measurements revealed that the CAS phase decomposes into three-phase assemblage of cubic Al-bearing CaSiO3 perovskite, Al2O3 corundum, and SiO2 stishovite above 30 GPa and 2,000 K with a positive pressure–temperature slope. Present results have important implications
for the subsolidus mineral assemblage of subducted sediment and the melting phase relation of basalt in the lower mantle. 相似文献
86.
87.
Shigehiko Tateno Kei Hirose Nagayoshi Sata Yasuo Ohishi 《Earth and Planetary Science Letters》2009,277(1-2):130-136
We have determined the post-perovskite phase transition boundary in MgSiO3 in a wide temperature range from 1640 to 4380 K at 119–171 GPa on the basis of synchrotron X-ray diffraction measurements in-situ at high-pressure and -temperature in a laser-heated diamond-anvil cell (LHDAC). The results show a considerably high positive Clapeyron slope of + 13.3 ± 1.0 MPa/K and a transition temperature of about 3520 ± 70 K at the core–mantle boundary (CMB) pressure. The thermal structure in D″ layer can be tightly constrained from precisely determined post-perovskite phase transition boundary and the depths of paired seismic discontinuities. These suggest that temperature at the CMB may be around 3700 K, somewhat lower than previously thought. A minimum bound on the global heat flow from the core is estimated to be 6.6 ± 0.5 TW. 相似文献
88.
我们对日本西南部南海俯冲板块界面过渡带发生的超低频地震进行报道。由矩震级为3.1~3.5的超低频地震引起的地震波显示其卓越长周期约为20s。超低频地震活动伴随深源低频颤动和慢滑事件同时发生,并随之移动。慢地震一直被认为会增加向上倾斜的大型逆冲地震断裂带上的应力,而这3种现象的同时发生提高了人们对慢地震的探测和特性鉴定水平。 相似文献
89.
Song JY Nakayama K Murakami Y Jung SJ Oh MJ Matsuoka S Kawakami H Kitamura S 《Marine pollution bulletin》2008,57(6-12):889-894
As basic research for the effect of heavy oil on the fish immune system, in this study, the number of leukocyte was counted in Japanese flounder Paralichthys olivaceus, after exposure to heavy oil at a concentration of 30 g/8L for 3 days. To compare the numbers of bacteria in the skin mucus between oil-exposed and control fish, viable bacteria were enumerated by counting colony forming unit (CFU). Compared with 5.79+/-1.88 x 10(7)leukocytes/mL in the controls, the exposed fish demonstrated higher counts, averaging 1.45+/-0.45 x 10(8)cells/mL. The bacterial numbers of control fish were 4.27+/-3.68 x 10(4)CFU/g, whereas they were 4.58+/-1.63 x 10(5)CFU/g in the exposed fish. The results suggest that immune suppression of the fish occurred due to heavy oil stressor, and bacteria could invade in the mucus, resulting in the increasing leukocyte number to prevent infectious disease. 相似文献
90.
T Horiguchi N Takiguchi H S Cho M Kojima M Kaya H Shiraishi M Morita H Hirose M Shimizu 《Marine environmental research》2000,50(1-5):223-229
Histological examination of gonads as well as chemical analysis of organotin compounds in tissues of the giant abalone, Haliotis madaka, was conducted to evaluate possible endocrine disruption and to consider the causal factors for the decline of abalone stocks in Japan. Abalone specimens were collected from two different areas, Tsushima as a reference site and Jogashima as a site representative of declining abalone populations, each month from September 1995 to November 1996. Scores were given to the development stages of reproductive cells in the ovary and testis. The degree of sexual maturation was evaluated by calculating the mean value of a histogram of these scores for the reproductive cells of each abalone. The temporal variations in degree of sexual maturation showed that female and male abalone from Tsushima matured synchronously, while those from Jogashima did not. The observed maximum reproductive developmental score in abalone from Jogashima was much lower than that from Tsushima, because immature females were present at the former site throughout the spawing season. Approximately 20% of the abalone from Jogashima were masculinized females with an ovo-testis. The masculinization of female abalone was similar to the imposex, typically induced in other gastropod molluscs by tributyltin (TBT) and triphenyltin (TPhT) from antifouling paints. Concentrations of TBT and TPhT in the muscles of abalone from Jogashima (n = 83) of 4.9 +/- 4.4 ng/g wet wt and 6.3 +/- 6.6 ng/g wet wt, respectively, were significantly higher than those from Tsushima (n = 125) (P < 0.01) of 0.8 +/- 0.8 ng/g wet wt and 0.6 +/- 1.3 ng/g wet wt, respectively. In situ exposure of abalone from Tsushima caged near a dockyard in Jogashima for 7 months (from the immature to the mature stage) resulted in spermatogenesis in the ovary of approximately 90% of females. Endocrine disruption may be caused in the giant abalone by organotin compounds from antifouling paints, which are possibly one of the causal factors for the decline of Japanese abalone stocks. 相似文献