全文获取类型
收费全文 | 12217篇 |
免费 | 77篇 |
国内免费 | 25篇 |
专业分类
安全科学 | 129篇 |
废物处理 | 874篇 |
环保管理 | 1974篇 |
综合类 | 1191篇 |
基础理论 | 3695篇 |
环境理论 | 1篇 |
污染及防治 | 2302篇 |
评价与监测 | 1155篇 |
社会与环境 | 963篇 |
灾害及防治 | 35篇 |
出版年
2023年 | 14篇 |
2022年 | 21篇 |
2021年 | 30篇 |
2020年 | 20篇 |
2019年 | 33篇 |
2018年 | 1508篇 |
2017年 | 1406篇 |
2016年 | 1243篇 |
2015年 | 175篇 |
2014年 | 67篇 |
2013年 | 297篇 |
2012年 | 562篇 |
2011年 | 1448篇 |
2010年 | 785篇 |
2009年 | 697篇 |
2008年 | 1006篇 |
2007年 | 1352篇 |
2006年 | 133篇 |
2005年 | 117篇 |
2004年 | 117篇 |
2003年 | 159篇 |
2002年 | 189篇 |
2001年 | 71篇 |
2000年 | 57篇 |
1999年 | 28篇 |
1998年 | 54篇 |
1997年 | 28篇 |
1996年 | 40篇 |
1995年 | 47篇 |
1994年 | 33篇 |
1993年 | 45篇 |
1992年 | 36篇 |
1991年 | 15篇 |
1990年 | 23篇 |
1989年 | 17篇 |
1988年 | 27篇 |
1987年 | 16篇 |
1986年 | 19篇 |
1985年 | 28篇 |
1984年 | 35篇 |
1983年 | 35篇 |
1982年 | 36篇 |
1981年 | 35篇 |
1980年 | 32篇 |
1979年 | 21篇 |
1978年 | 24篇 |
1977年 | 11篇 |
1976年 | 8篇 |
1973年 | 7篇 |
1972年 | 10篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
A fragment constant QSAR model for evaluating the EC50 values of organic chemicals to Daphnia magna.
Shu Tao Xiaohuan Xi Fuliu Xu Bengang Li Jun Cao R Dawson 《Environmental pollution (Barking, Essex : 1987)》2002,116(1):57-64
The quantitative relationship between the median effective concentration (EC50) of organic chemicals to Daphnia magna and the number of molecular fragments was investigated based on experimental EC50 values for 217 chemicals derived from the literature. A fragment constant model was developed based on a multivariate linear regression between the number of fragments and the logarithmically transformed reciprocal values of EC50. Functional correction factors were introduced into the model. The model was verified using an independent set of randomly selected data. The mean residual of the final model was 0.4 log-units. The robustness of the model was discussed based on the results of three jackknife tests. 相似文献
2.
3.
4.
Dr. J. F. Bruch P. Metezeau N. Garcia-Fonknechten Y. Richard V. Tricottet B.-L. Hsi A. Kitzis C. Julien E. Papiernik 《黑龙江环境通报》1991,11(10):787-798
Three monoclonal antibodies (MAbs) against trophoblast (GB17, GB21, and GB25) and flow cytometry were used to sort trophoblast-like cells (TLCs) from peripheral blood of pregnant women. Sorted TLCs were processed for electron microscopy and fetal DNA amplification of the Y-specific sequences from mothers carrying male fetuses. At the ultra-structural level, most of the nucleated cells had the morphology of leucocytes, suggesting maternal contaminants, and we did not find the characteristic features of the free inter-villous trophoblast cells. Nevertheless, polymerase chain reaction (PCR) analysis showed an amplification of Y-specific sequences in two out of three samples of sorted TLCs. These results suggest that besides the maternal leucocytes, sufficient trophoblast nucleated fetal cells can be obtained using cell enrichment by sorting. This sensitive method holds promise for non-invasive prenatal diagnosis of fetal sex and if sufficient Y(positive) nuclei are found, for the diagnosis of selected numerical chromosome abnormalities. 相似文献
5.
Critical loads offer a unique way of evaluating impacts of acid deposition by quantifying environmental sensitivity. The critical loads of acidity for UK peat soils have been based upon an arbitrary reduction in pH of 0.2 units. This chemical shift needs to be better related to adverse effects on sensitive biological receptors. It is known that effective precipitation pH equates closely to soil solution pH, and the latter is directly linkable to biotic effects of pH change. On continuation of a long-term experiment assessing impacts of simulated acid rain on peat microcosms in a realistic outdoor environment, Calluna vulgaris continued to flourish at acid deposition loads well above the existing critical load. Calluna plants were harvested and analysed, and acid deposition treatments to the microcosms continued to allow natural vegetation to regenerate. A diverse mixture of moorland plants and bryophytes established at acidity treatments well above the existing critical load, and only a very high acid load resulted in no natural regeneration. A critical effective rain pH value of 3.6 is suggested as a basis for setting critical loads. At this pH, Calluna grows well, and a healthy diverse vegetation community re-establishes when harvested. It is suggested that the peat critical load should be set at the acid load that, at any specific site, would result in a mean effective precipitation pH of 3.6. 相似文献
6.
7.
8.
9.
The lessons of history indicate that mismanagement of natural resources and the environment often leads to potentially adverse consequences.The increasing interest in economic development,particularly in the developing countries of the world coupled with increasing population pressures and the globalization of economic activity is placing noticeable stresses on the ultimate sustainability of both human and environmental systems.Sustainable development is not a new concept.It has been an area of concern for different elements of society for some time.Yet efforts to understand the implications of sustainable development have not,until recently,been formalized.We have focused singularly on economic development and environmental quality as if they were mutually exclusive.This paper focuses on the concept of concurrency as both a conceptual framework and practicable method of understanding and implementing the ecology and economy of sustainability. 相似文献
10.
Yves Dumez Marc Dommergues Marie-Claire Gubler Victor Bunduki Francoise Narcy Martine Lemerrer Laurent Mandelbrot Richard Berkowitz 《黑龙江环境通报》1994,14(2):141-144
A case of Meckel—Gruber syndrome was diagnosed by embryoscopy at 10 menstrual weeks, allowing for early termination of pregnancy. Post-mortem examination confirmed the presence of polydactyly and bilateral cystic lesions of the mesonephros and metanephros. Both the forming nephrons and the collecting ducts were involved in the formation of renal cysts. 相似文献