全文获取类型
收费全文 | 473篇 |
免费 | 9篇 |
国内免费 | 14篇 |
专业分类
测绘学 | 11篇 |
大气科学 | 14篇 |
地球物理 | 145篇 |
地质学 | 137篇 |
海洋学 | 75篇 |
天文学 | 57篇 |
综合类 | 14篇 |
自然地理 | 43篇 |
出版年
2022年 | 3篇 |
2021年 | 3篇 |
2020年 | 3篇 |
2019年 | 3篇 |
2018年 | 6篇 |
2017年 | 8篇 |
2016年 | 15篇 |
2015年 | 7篇 |
2014年 | 20篇 |
2013年 | 31篇 |
2012年 | 13篇 |
2011年 | 27篇 |
2010年 | 16篇 |
2009年 | 26篇 |
2008年 | 24篇 |
2007年 | 21篇 |
2006年 | 12篇 |
2005年 | 20篇 |
2004年 | 12篇 |
2003年 | 19篇 |
2002年 | 16篇 |
2001年 | 15篇 |
2000年 | 11篇 |
1999年 | 15篇 |
1998年 | 13篇 |
1997年 | 9篇 |
1995年 | 8篇 |
1994年 | 10篇 |
1993年 | 7篇 |
1992年 | 5篇 |
1991年 | 7篇 |
1990年 | 6篇 |
1989年 | 11篇 |
1988年 | 7篇 |
1987年 | 7篇 |
1986年 | 7篇 |
1985年 | 4篇 |
1984年 | 8篇 |
1983年 | 2篇 |
1982年 | 5篇 |
1981年 | 4篇 |
1980年 | 5篇 |
1979年 | 5篇 |
1978年 | 3篇 |
1977年 | 4篇 |
1976年 | 3篇 |
1975年 | 2篇 |
1973年 | 3篇 |
1971年 | 1篇 |
1969年 | 1篇 |
排序方式: 共有496条查询结果,搜索用时 296 毫秒
151.
152.
Poh Poh Wong 《Ocean & Coastal Management》2009,52(7):405-410
The December 2004 Indian Ocean tsunami wrought environmental damage beyond the normal framework of integrated coastal management and has implications for coastal management in Asia-Pacific in the post-tsunami phase. Fieldwork conducted on the coasts of four tsunami-affected countries in 2005 and 2006 identified several “practitioner-type” issues that would have implications for ICM policy. These include the loss of land with accompanying land tenure problems; the safety zone in conflict with the buffer zone; the need for better integration of livelihoods restoration with the rehabilitation of coastal ecosystems; and the inclusion of tsunami mitigation in the larger framework of climate change mitigation. A discussion of these issues and future role of ICM would provide a fresh perspective to policy-practice of ICM. A proposal is made to study various development pathways of selected coastal villages as they recovered in the post-tsunami phase. 相似文献
153.
154.
L. C. Abdullah Ph.D. L. L. Wong M.Sc. M. Saari Ph.D. A. Salmiaton Ph.D. M. S. Abdul Rashid Ph.D. 《International Journal of Environmental Science and Technology》2007,4(2):271-278
The emissions from palm oil industry through incineration and open burning are the major sources of air pollutions contribution in Malaysia. The consequence of increasing the particulate concentration, the particulate matter dissolves with vapour and grows into droplets when the humidity exceeds approximately 70% and causing opaque situation known as haze. This work focuses on the dispersion particulate matter from palm oil mill. Gaussian Plume Model from a point source, subject to various atmospheric conditions is used to calculate particulate matter concentration then display the distribution of plume dispersion using geographic information system. Atmospheric Stability, mixing height, wind direction, wind speed, natural and artificial features play an important role in dispersion process. Study on the dispersion of particulate matters and the haze potential are presented as a case study in this paper. The data obtained will be served as the purpose of modeling the transport of particulate matter for obtaining permits and prevention of significant deterioration to the environment. 相似文献
155.
N. H. Wong B.Sc. M.Sc. P. L. Law BSCE MSCE M.Sc. S. H. Lai B.Sc. M.Sc. Ph.D. 《International Journal of Environmental Science and Technology》2007,4(3):345-350
This study investigates the field performance tests of a commercial grease trap effluent filter for removal of total suspended solids, and oil and grease discharged from the clear zone of full service restaurant grease traps. The grease trap effluent filters were installed on 1,000-gallon, 2,000-gallon and 5,400-gallon full service restaurant grease traps over a period of 8 weeks, and samples were taken at the inlets and outlets. On average, the effluent filters demonstrated to be capable of removing 41% to 57% of TSS, and 43% to 52% of O and G. Field test data also showed that the total amount of TSS removed by the grease trap effluent filter installed on 1,000 gallon, 2,000 gallon and 5,400 gallon grease traps were approximately 2,542 kg, 709 kg, and 2,319 kg, respectively; and the total amount of O and G removed over the same period were approximately 1,104 kg, 271 kg, and 897 kg, respectively. 相似文献
156.
We comment on the recent paper by A.D. Dolgov, S.H. Hansen, S. Pastor and D.V. Semikoz (DHPS) [Astropart. Phys. 14 (2000) 79] on the generation of neutrino asymmetries from active–sterile neutrino oscillations. We demonstrate that the approximate asymmetry evolution equation obtained therein is an expansion, up to a minor discrepancy, of the well-established static approximation equation, valid only when the supposedly new higher order correction term is small. In the regime where this so-called “back-reaction” term is large and artificially terminates the asymmetry growth, their evolution equation ceases to be a faithful approximation to the quantum kinetic equations simply because pure Mikheyev–Smirnov–Wolfenstein (MSW) transitions have been neglected. At low temperatures the MSW effect is the dominant asymmetry amplifier. Neither the static nor the DHPS approach contains this important physics. Therefore we conclude that the DHPS results have sufficient veracity at the onset of explosive asymmetry generation, but are invalid in the ensuing low temperature epoch where MSW conversions are able to enhance the asymmetry to values of order 0.2–0.37. DHPS do claim to find a significant final asymmetry for very large δm2 values. However, for this regime the effective potential they employed is not valid. 相似文献
157.
W. L. Sjogren P. M. Muller P. Gottlieb L. Wong G. Buechler W. Downs R. Prislin 《Earth, Moon, and Planets》1971,2(3):338-353
Combined efforts of the Jet Propulsion Laboratory and Aerospace Corporation have provided a front side lunar gravity field using the Doppler tracking data from the United States Lunar Orbiters IV and V. Data reduction was accomplished with a model which included all dynamical motion due to gravitational perturbations, as well as all tracking geometries. The field is represented as a grid of 580 surface mass points which are contoured and show correlations with various lunar surface features.This paper presents the results of one phase of research carried out at the Jet Propulsion Laboratory, California Institute of Technology, under Contract No. NAS 7-100, sponsored by the National Aeronautics and Space Administration. 相似文献
158.
159.
160.
Toxicity identification evaluation (TIE) of pore water of contaminated marine sediments collected from Hong Kong waters 总被引:2,自引:0,他引:2
Marine sediment can function both as a source and as a sink of marine chemical contaminants. The toxicity of contaminated marine sediment can be assessed by toxic evaluation of its pore water, the inter-particle water of sediment, because toxicants in the pore water may be bioavailable to marine organisms. In this study, the toxicity identification evaluation (TIE) was performed to identify the major toxicants in the pore water of marine sediment collected in Hong Kong waters. In Phase 1 TIE, the suspected toxicants were characterized as anions or organic compounds that are either oxidizable or filterable in alkaline medium. In Phase 2 TIE, the suspected toxicants were identified as sulfide (S2−) based on the reduction of toxicity due to lowering of sulfide concentrations by experimental manipulations. The mass balance and spiking analyses in Phase 3 confirmed that S2− was one of the major toxicants and that some non-toxic unknown compounds measured by LC–MS, which was removed by C18 solid phase extraction, enhanced the toxicity of S2− in the pore water samples. 相似文献