全文获取类型
收费全文 | 9896篇 |
免费 | 368篇 |
国内免费 | 3839篇 |
专业分类
安全科学 | 750篇 |
废物处理 | 646篇 |
环保管理 | 868篇 |
综合类 | 5175篇 |
基础理论 | 1662篇 |
环境理论 | 2篇 |
污染及防治 | 3870篇 |
评价与监测 | 400篇 |
社会与环境 | 333篇 |
灾害及防治 | 397篇 |
出版年
2024年 | 6篇 |
2023年 | 156篇 |
2022年 | 487篇 |
2021年 | 397篇 |
2020年 | 288篇 |
2019年 | 271篇 |
2018年 | 361篇 |
2017年 | 458篇 |
2016年 | 526篇 |
2015年 | 676篇 |
2014年 | 816篇 |
2013年 | 1055篇 |
2012年 | 921篇 |
2011年 | 901篇 |
2010年 | 693篇 |
2009年 | 661篇 |
2008年 | 745篇 |
2007年 | 593篇 |
2006年 | 513篇 |
2005年 | 375篇 |
2004年 | 290篇 |
2003年 | 355篇 |
2002年 | 304篇 |
2001年 | 252篇 |
2000年 | 260篇 |
1999年 | 244篇 |
1998年 | 249篇 |
1997年 | 242篇 |
1996年 | 222篇 |
1995年 | 173篇 |
1994年 | 118篇 |
1993年 | 122篇 |
1992年 | 104篇 |
1991年 | 79篇 |
1990年 | 54篇 |
1989年 | 26篇 |
1988年 | 27篇 |
1987年 | 10篇 |
1986年 | 17篇 |
1985年 | 11篇 |
1984年 | 11篇 |
1983年 | 8篇 |
1982年 | 9篇 |
1981年 | 8篇 |
1975年 | 1篇 |
1974年 | 2篇 |
1973年 | 1篇 |
1972年 | 2篇 |
1971年 | 1篇 |
1968年 | 1篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
951.
岷江上游山地生态系统的退化及其恢复与重建对策 总被引:51,自引:5,他引:51
阐述了岷江上游山地生态系统的主要特征及主要由人类活动引起的森林、草地、农用地和整个山地生态系统环境退化现状。在此基础上,提出了岷江上游退化山地生态系统恢复与重建的对策,即加强资源和环境的合理利用和保护,提高全民环境保护意识;分区分类治理;不同区城不同退化亚系统采取不同的技术方法。同时,就恢复与重建过程中应注意的几个问题出提出了解决的思路和方法。 相似文献
952.
Jiao Youzhou Xue Huizan He Chao Wang Zigang Ma Xiaoran Liu Xinxin Liu Liang Chang Chun Petracchini Francesco Li Panpan 《Environment, Development and Sustainability》2022,24(4):4709-4726
Environment, Development and Sustainability - Anaerobic digestion (AD) is an attractive straw resource treatment technology as it can improve the utilization efficiency of straw resource. Raw straw... 相似文献
953.
954.
Tropospheric ozone is a secondary air pollutant produced in the presence of nitrogen oxides (NO_x),volatile organic compounds (VOCs),and solar radiation.In an urban environment,ground-level vehicular exhaust is the major anthropogenic source of ozone precursors.In the cases of street canyons,pollutant dilution is weakened by the surrounding buildings that creates localized high concentration of NO_x and VOCs,and thus leads to high potential of ozone formation.By considering the major physical and chemica... 相似文献
955.
多频管中电流法通过计算管道防腐层绝缘电阻来判断管道外防腐层的状态,近年来得到较为广泛的应用.但对于丘陵山地的埋地输油气气管道,其评价结果与实际状态有一定差距.通过研究发现,评价结果与实际状态不符的主要原因是:管道分布电容、管道分布电感在GDWFF处理软件中对防腐层评价结果影响较大,尤其是管道分布电感是关键参数.为此,修正了多频管中电流法评价软件给出的管道分布电感推荐值,并采用现场开挖的方式进行验证,说明评价结果更符合山地实际. 相似文献
956.
957.
958.
A new captorhinid reptile, Gansurhinus qingtoushanensis, gen. et sp. nov., from the Permian of China
Captorhinids, a clade of Paleozoic reptiles, are represented by a rich fossil record that extends from the Late Carboniferous into the Late Permian. Representatives of this clade dispersed from the equatorial regions of Laurasia into the temperate regions of Pangea during the Middle and Late Permian. This rich fossil record shows that there was an evolutionary trend from faunivorous to omnivorous and herbivorous feeding habits within this clade. The discovery of well-preserved captorhinid materials in the Middle Permian of China allows us to determine that the new taxon, Gansurhinus qingtoushanensis, gen. et sp. nov, is a member of Moradisaurinae, a clade of captorhinids with multiple tooth rows arranged in parallel. The presence of this moradisaurine in the Middle Permian of south central Asia leads us to suggest that paleogeographic changes during the Permian, with part of what is today China becoming a large peninsula of Pangea, allowed these early reptiles as well as other terrestrial vertebrates to extend their geographic ranges to this region of the Late Paleozoic supercontinent. 相似文献
959.
960.
Harish Venkatakrishnan Youming Tan Maszenan bin Abdul Maji Santosh Pathak Antonius Yudi Sendjaj Dongzhe Li Jerry Jian Lin Liu Yan Zhou Wun Jern Ng 《环境科学学报(英文版)》2014,26(4):875-884
A high strength chemical industry wastewater was assessed for its impact on anaerobic microbial com- munity dynamics and consequently mesophilic methane generation. Cumulative methane production was 251 mL/g total chemical oxygen demand removed at standard temperature and pressure at the end of 30 days experimental period with a highest recorded methane percentage of 80.6% of total biogas volume. Volatile fatty acids (VFAs) analysis revealed that acetic acid was the major intermediate VFAs produced with propionic acid accumulating over the experimental period. Quantitative analysis of microbial communities in the test and control groups with quantitative real time polymerase chain reaction highlighted that in the test group, Eubacteria (96.3%) was dominant in comparison with methanogens (3.7%). The latter were dominated by Methanomicrobiales and Methanobacteriales while in test groups increased over the experimental period, reaching a maximum on day 30. Denaturing gradient gel electrophoresis profile was performed, targeting the 16S rRNA gene of Eubacteria and Archaea, with the DNA samples extracted at 3 different time points from the test groups. A phylogenetic tree was constructed for the sequences using the neighborhood joining method. The analysis revealed that the presence of organisms resembling Syntrophomonadaceae could have contributed to increased production of acetic and propionic acid intermediates while decrease of organisms resembling Pelotomaculum sp. could have most likely contributed to accumulation of propionic acid. This study suggested that the degradation of organic components within the high strength industrial wastewater is closely linked with the activity of certain niche microbial communities within eubacteria and methanogens. 相似文献