全文获取类型
收费全文 | 19164篇 |
免费 | 220篇 |
国内免费 | 151篇 |
专业分类
安全科学 | 532篇 |
废物处理 | 776篇 |
环保管理 | 2442篇 |
综合类 | 3479篇 |
基础理论 | 4678篇 |
环境理论 | 13篇 |
污染及防治 | 5009篇 |
评价与监测 | 1292篇 |
社会与环境 | 1180篇 |
灾害及防治 | 134篇 |
出版年
2023年 | 92篇 |
2022年 | 209篇 |
2021年 | 209篇 |
2020年 | 151篇 |
2019年 | 201篇 |
2018年 | 307篇 |
2017年 | 343篇 |
2016年 | 489篇 |
2015年 | 382篇 |
2014年 | 534篇 |
2013年 | 1636篇 |
2012年 | 664篇 |
2011年 | 874篇 |
2010年 | 657篇 |
2009年 | 709篇 |
2008年 | 830篇 |
2007年 | 855篇 |
2006年 | 762篇 |
2005年 | 640篇 |
2004年 | 584篇 |
2003年 | 570篇 |
2002年 | 511篇 |
2001年 | 606篇 |
2000年 | 461篇 |
1999年 | 272篇 |
1998年 | 217篇 |
1997年 | 205篇 |
1996年 | 217篇 |
1995年 | 236篇 |
1994年 | 226篇 |
1993年 | 216篇 |
1992年 | 229篇 |
1991年 | 215篇 |
1990年 | 217篇 |
1989年 | 182篇 |
1988年 | 163篇 |
1987年 | 134篇 |
1986年 | 157篇 |
1985年 | 160篇 |
1984年 | 161篇 |
1983年 | 166篇 |
1982年 | 158篇 |
1981年 | 163篇 |
1980年 | 151篇 |
1979年 | 148篇 |
1978年 | 109篇 |
1977年 | 121篇 |
1974年 | 110篇 |
1973年 | 91篇 |
1972年 | 108篇 |
排序方式: 共有10000条查询结果,搜索用时 546 毫秒
301.
S.M.Semenov 《环境科学学报(英文版)》1992,4(1):10-14
An integrated approach was developed to determine the critical levels of air pollution for ecological standard setting based on the unified index of biological response, by taking into account the effects of all pollution components simultaneously. An empirical model of plant productivity was taken as the dose response model for gaseous pollutant effect on the productivity of trees and the annual productivity of plants was used as the above mentioned index. The CO2 increase in the lower atmosphere was considered to potentially increase plant productivity and NO2 was estimated as neutral while being dangerous for plants as a chemical precursor of ozone or as a source of acidification. The maximum permissible chronic O3 and SO2 levels for trees were estimated and it was found that O3 is much more phytotoxic, as compared to SO2 , with a rather narrow range of permissible levels (27-33 ppb) which complicates its monitoring and control. 相似文献
302.
303.
304.
305.
306.
307.
308.
The “Linh Duong” (Pseudonovibos spiralis), a newly described Vietnamese bovid, has been shown to be related to the Caprinae on the basis of the mitochondrial cytochrome
b gene sequencing from horn fragments. To integrate the greatest available biodiversity we performed a new phylogenetic analysis
including all genera of Caprinae. Unexpectedly, Pseudonovibos is found to be robustly associated with Rupicapra, and closer to the Alpine than to the Pyrenean chamois. Several clues led us to interpret this result as a carry-over DNA
contamination of Pseudonovibos by Rupicapra.
Received: 19 July 1999 / Accepted in revised form: 20 October 1999 相似文献
309.
310.
Maternal serum CA 125 levels were determined at 9–11 menstrual weeks for 26 cases of trisomy 13 (n = 4), trisomy 18 (n = 7), trisomy 21 (n = 15), and appropriate controls. There were no statistically significant differences between groups. 相似文献