全文获取类型
收费全文 | 16682篇 |
免费 | 159篇 |
国内免费 | 149篇 |
专业分类
安全科学 | 464篇 |
废物处理 | 502篇 |
环保管理 | 2386篇 |
综合类 | 3957篇 |
基础理论 | 4282篇 |
环境理论 | 7篇 |
污染及防治 | 3989篇 |
评价与监测 | 784篇 |
社会与环境 | 546篇 |
灾害及防治 | 73篇 |
出版年
2018年 | 246篇 |
2017年 | 263篇 |
2016年 | 378篇 |
2015年 | 225篇 |
2014年 | 235篇 |
2013年 | 1021篇 |
2012年 | 736篇 |
2011年 | 675篇 |
2010年 | 366篇 |
2009年 | 468篇 |
2008年 | 538篇 |
2007年 | 587篇 |
2006年 | 531篇 |
2005年 | 738篇 |
2004年 | 876篇 |
2003年 | 802篇 |
2002年 | 385篇 |
2001年 | 513篇 |
2000年 | 348篇 |
1999年 | 251篇 |
1998年 | 163篇 |
1997年 | 157篇 |
1996年 | 189篇 |
1995年 | 194篇 |
1994年 | 209篇 |
1993年 | 183篇 |
1992年 | 186篇 |
1991年 | 189篇 |
1990年 | 215篇 |
1989年 | 197篇 |
1988年 | 168篇 |
1987年 | 163篇 |
1986年 | 149篇 |
1985年 | 169篇 |
1984年 | 152篇 |
1983年 | 161篇 |
1982年 | 163篇 |
1981年 | 165篇 |
1980年 | 150篇 |
1979年 | 147篇 |
1978年 | 145篇 |
1977年 | 129篇 |
1976年 | 137篇 |
1975年 | 118篇 |
1974年 | 145篇 |
1973年 | 126篇 |
1972年 | 127篇 |
1971年 | 107篇 |
1970年 | 107篇 |
1967年 | 123篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
Mahaney WC Wilson E Boyer MG Hancock RG 《Environmental pollution (Barking, Essex : 1987)》1995,87(1):71-75
Recent lichen surveys in the foreland of The Syterb?cken glacier reveal that the crustose lichens, principally species of Rhizocarpon section Rhizocarpon, exhibit marginal bleaching, readily distinguishable from normal pigmented forms. The largest elliptical thallus of Rhizocarpon measured 290 mm maximum diameter on a bedrock outcrop beyond the margin of Little Ice Age moraines in the upper Syterb?cken Valley. Many small and large thalli of Rhizocarpon suffered damage to the periphery of individual thalli. We examine here some of the possible hypotheses explaining these occurrences. Among others, these are bedrock lithology, ice crystal blasting, long-term snowbank cover, ultraviolet exposure and acid rain. While at this time none of the possibilities can be ruled out entirely, acid rain would appear to be at least one of the factors involved. Acid rain, which is known to produce a soil pH as low as 3.3 in the field area, appears to provide a high input of H(+) ions that the lichen algal component cannot withstand. However, the lack of similar effects on associated foliose or fruticose forms raises the possibility that perhaps two or more factors specific to the environment of Rhizocarpon are operating. 相似文献
92.
Becker E. W. Bier W. Ehrfeld W. Schubert K. Schütte R. Seidel D. 《Die Naturwissenschaften》1976,63(9):407-411
The Science of Nature - The development of reliable manufacturing methods for commercial separation elements, the successful operation of separative stages, and extensive tests performed on plant... 相似文献
93.
The modern theory of biological evolution: an expanded synthesis 总被引:12,自引:2,他引:12
In 1858, two naturalists, Charles Darwin and Alfred Russel Wallace, independently proposed natural selection as the basic mechanism responsible for the origin of new phenotypic variants and, ultimately, new species. A large body of evidence for this hypothesis was published in Darwins Origin of Species one year later, the appearance of which provoked other leading scientists like August Weismann to adopt and amplify Darwins perspective. Weismanns neo-Darwinian theory of evolution was further elaborated, most notably in a series of books by Theodosius Dobzhansky, Ernst Mayr, Julian Huxley and others. In this article we first summarize the history of life on Earth and provide recent evidence demonstrating that Darwins dilemma (the apparent missing Precambrian record of life) has been resolved. Next, the historical development and structure of the modern synthesis is described within the context of the following topics: paleobiology and rates of evolution, mass extinctions and species selection, macroevolution and punctuated equilibrium, sexual reproduction and recombination, sexual selection and altruism, endosymbiosis and eukaryotic cell evolution, evolutionary developmental biology, phenotypic plasticity, epigenetic inheritance and molecular evolution, experimental bacterial evolution, and computer simulations (in silico evolution of digital organisms). In addition, we discuss the expansion of the modern synthesis, embracing all branches of scientific disciplines. It is concluded that the basic tenets of the synthetic theory have survived, but in modified form. These sub-theories require continued elaboration, particularly in light of molecular biology, to answer open-ended questions concerning the mechanisms of evolution in all five kingdoms of life.Dedicated to Prof. Dr. Dr. hc mult. Ernst Mayr on the occasion of his 100th birthdayThis revised version was published online in March 2004, with corrections to the caption of Figure 6. 相似文献
94.
Part of the work was supported by the Bundesministerium für Forschung und Technologie, the Deutsche Forschungsgemeinschaft, the Fonds der Chemischen Industrie, and from the Carl Zeiss, Hoechst, and Ernst Leitz companies. Special thanks are due to Dr. K. Wahn, Department of Virology, University of Giessen, for conducting the electron microscope and phase-contrast investigations, to Prof. G. Sauer, German Cancer Research Center, Heidelberg, and Dr. W. R. Willems, Department of Medical Virology, University of Giessen, for supplying the different cell lines. 相似文献
95.
96.
The Science of Nature - 相似文献
97.
E. Lamla F. Boschke G. Traving G. Pfotzer H. Wolter W. Walcher H. D. Dahmen H. J. Queisser W. W. Klingbeil K. Beyermann O. Müller R. R. Ernst D. Reinen H. Muth W. Becker G. Wunsch G. I. Distler L. Jaenicke H. G. v. Schnering H. Werner F. Reiff H. Schimassek W. Höll H. K. Vasil W. F. Angermeier W. Ruppel J. C. Eccles G. Spiteller H. Oettel W. Vogell P. Brosche K. J. Hsü H. -U. Schmincke 《Die Naturwissenschaften》1975,62(3):143-143
98.
The Science of Nature - 相似文献
99.
100.