全文获取类型
收费全文 | 25515篇 |
免费 | 237篇 |
国内免费 | 120篇 |
专业分类
安全科学 | 526篇 |
废物处理 | 1140篇 |
环保管理 | 3440篇 |
综合类 | 3837篇 |
基础理论 | 7527篇 |
环境理论 | 10篇 |
污染及防治 | 5884篇 |
评价与监测 | 1644篇 |
社会与环境 | 1730篇 |
灾害及防治 | 134篇 |
出版年
2021年 | 137篇 |
2019年 | 128篇 |
2018年 | 763篇 |
2017年 | 737篇 |
2016年 | 818篇 |
2015年 | 355篇 |
2014年 | 480篇 |
2013年 | 1608篇 |
2012年 | 766篇 |
2011年 | 1478篇 |
2010年 | 1064篇 |
2009年 | 1086篇 |
2008年 | 1394篇 |
2007年 | 1638篇 |
2006年 | 771篇 |
2005年 | 753篇 |
2004年 | 679篇 |
2003年 | 715篇 |
2002年 | 732篇 |
2001年 | 775篇 |
2000年 | 583篇 |
1999年 | 329篇 |
1998年 | 281篇 |
1997年 | 278篇 |
1996年 | 280篇 |
1995年 | 331篇 |
1994年 | 305篇 |
1993年 | 285篇 |
1992年 | 278篇 |
1991年 | 278篇 |
1990年 | 295篇 |
1989年 | 278篇 |
1988年 | 249篇 |
1987年 | 240篇 |
1986年 | 222篇 |
1985年 | 200篇 |
1984年 | 265篇 |
1983年 | 213篇 |
1982年 | 271篇 |
1981年 | 219篇 |
1980年 | 184篇 |
1979年 | 201篇 |
1978年 | 184篇 |
1977年 | 153篇 |
1976年 | 138篇 |
1975年 | 143篇 |
1974年 | 159篇 |
1973年 | 162篇 |
1972年 | 148篇 |
1971年 | 146篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
171.
Pelgrom SM Lamers LP Lock RA Balm PH Bonga SE 《Environmental pollution (Barking, Essex : 1987)》1995,90(3):415-423
Sexually mature female tilapia were exposed to sublethal concentrations of waterborne Cu and/or Cd over 6 days, and subsequent body concentrations of these metals were determined in several organs. The results show that the distribution of Cu and Cd was metal and organ specific. This is demonstrated, for example, by the observation that in tilapia, Cu exposure did not result in Cu accumulation in the liver, whereas in the intestinal wall, notably high concentrations of Cu and Cd were measured in metal exposed fish. In addition to single metal exposed fish, we also determined Cu and Cd body distribution in Cu?Cd co-exposed fish. The observed interactions in metal accumulation were most pronounced in the organs of fish exposed to low, environmentally realistic, metal concentrations. 相似文献
172.
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
173.
174.
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
175.
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
176.
177.
178.
179.
180.
Social insects use complex chemical communication systems to govern many aspects of their life. We studied chemical changes in Dufours gland secretions associated with ovary development in several genotypes of honeybees. We found that C28–C38 esters were associated only with cavity nesting honeybee queens, while the alcohol eicosenol was associated only with their non-laying workers. In contrast, both egg-laying anarchistic workers and all parasitic Cape workers from queenright colonies showed the typical queen pattern (i.e. esters present and eicosenol absent), while egg-laying wild-type and anarchistic workers in queenless colonies showed an intermediate pattern, producing both esters and eicosenol but at intermediate levels. Furthermore, neither esters nor eicosenol were found in aerial nesting honeybee species. Both esters and eicosenol are biosynthetically similar compounds since both are recognizable products of fatty acid biosynthesis. Therefore, we propose that in honeybees the biosynthesis of esters and eicosenol in the Dufours gland is caste-regulated and this pathway has been conserved over evolutionary time. 相似文献