全文获取类型
收费全文 | 25597篇 |
免费 | 268篇 |
国内免费 | 130篇 |
专业分类
安全科学 | 620篇 |
废物处理 | 1076篇 |
环保管理 | 3016篇 |
综合类 | 5153篇 |
基础理论 | 6806篇 |
环境理论 | 24篇 |
污染及防治 | 6578篇 |
评价与监测 | 1521篇 |
社会与环境 | 1062篇 |
灾害及防治 | 139篇 |
出版年
2021年 | 178篇 |
2019年 | 177篇 |
2018年 | 328篇 |
2017年 | 357篇 |
2016年 | 509篇 |
2015年 | 415篇 |
2014年 | 607篇 |
2013年 | 1853篇 |
2012年 | 695篇 |
2011年 | 1053篇 |
2010年 | 804篇 |
2009年 | 811篇 |
2008年 | 1062篇 |
2007年 | 1068篇 |
2006年 | 934篇 |
2005年 | 812篇 |
2004年 | 768篇 |
2003年 | 745篇 |
2002年 | 758篇 |
2001年 | 873篇 |
2000年 | 665篇 |
1999年 | 387篇 |
1998年 | 316篇 |
1997年 | 321篇 |
1996年 | 328篇 |
1995年 | 383篇 |
1994年 | 372篇 |
1993年 | 321篇 |
1992年 | 322篇 |
1991年 | 322篇 |
1990年 | 335篇 |
1989年 | 309篇 |
1988年 | 273篇 |
1987年 | 261篇 |
1986年 | 251篇 |
1985年 | 229篇 |
1984年 | 285篇 |
1983年 | 232篇 |
1982年 | 298篇 |
1981年 | 257篇 |
1980年 | 209篇 |
1979年 | 222篇 |
1978年 | 208篇 |
1977年 | 181篇 |
1976年 | 175篇 |
1975年 | 172篇 |
1974年 | 182篇 |
1973年 | 189篇 |
1972年 | 173篇 |
1971年 | 165篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
R. Stakėnienė K. Jokšas A. Galkus E. Raudonytė-Svirbutavičienė 《Chemistry and Ecology》2016,32(4):357-377
A total of 22 bottom surface sediment samples were collected from Klaip?da Harbour, Lithuania (Baltic Sea). Sediment parameters, such as grain size and concentrations of total organic carbon, aliphatic hydrocarbons (ALHs) and polycyclic aromatic hydrocarbons (PAHs), were determined. Hydrocarbon contamination levels in the sediments were estimated based on classifications provided in the literature, and potential biological effects were assessed based on the effects range low–effects range median values of the Sediment Quality Guidelines and on the total toxic benzo(a)pyrene equivalent. The results demonstrated that concentrations of PAHs and total aliphatic hydrocarbons in the sediments varied between 1.6 and 5456?ng?g?1 d.w. and 6.9 and 727?μg?g?1 d.w., respectively. In most cases, the concentrations of ALHs and PAHs in the sediments indicated low to moderate levels of pollution and were not observed to have any significant adverse effects on living biota. To determine possible sources of hydrocarbons, hydrocarbon compositions were analysed, and ALHs’ and PAHs’ specific diagnostic ratios were calculated. According to the results, the Klaip?da Harbour bottom sediments were dominated by PAHs of pyrogenic origin, whereas the origin of ALHs was mixed, that is, anthropogenic with a biogenic (aquatic and terrestrial) input. 相似文献
992.
Biodegradation of N,N-bis(carboxymethyl)-L-glutamate and its utilization by micro-organisms in marine environments were studied in Organization of Economic Development and Cooperation (OECD) screening tests and with pure bacterial cultures. Biodegradation in excess of 60% was achieved in closed bottle tests in less than 60 days, suggesting complete degradation. The bacterial strain isolated from marine sandy sediment and utilizing N,N-bis(carboxymethyl)-L-glutamate as sole source of carbon, nitrogen, and energy was identified as Rhizobium radiobacter. The strain was capable to mineralize N,N-bis(carboxymethyl)-L-glutamate in seawater and in synthetic media containing 0–60 g L?1 sea salts. Growth and adaptation studies indicated that N-carboxymethyl-L-glutamate and L-glutamate are main metabolites. 相似文献
993.
Meng?GaoEmail author Gregory?R.?CarmichaelEmail author Yuesi?Wang Dongsheng?Ji Zirui?Liu Zifa?Wang 《Frontiers of Environmental Science & Engineering》2016,10(5):16
We implemented the online coupled WRF-Chem model to reproduce the 2013 January haze event in North China, and evaluated simulated meteorological and chemical fields using multiple observations. The comparisons suggest that temperature and relative humidity (RH) were simulated well (mean biases are–0.2K and 2.7%, respectively), but wind speeds were overestimated (mean bias is 0.5 m?s–1). At the Beijing station, sulfur dioxide (SO2) concentrations were overpredicted and sulfate concentrations were largely underpredicted, which may result from uncertainties in SO2 emissions and missing heterogeneous oxidation in current model. We conducted three parallel experiments to examine the impacts of doubling SO2 emissions and incorporating heterogeneous oxidation of dissolved SO2 by nitrogen dioxide (NO2) on sulfate formation during winter haze. The results suggest that doubling SO2 emissions do not significantly affect sulfate concentrations, but adding heterogeneous oxidation of dissolved SO2 by NO2 substantially improve simulations of sulfate and other inorganic aerosols. Although the enhanced SO2 to sulfate conversion in the HetS (heterogeneous oxidation by NO2) case reduces SO2 concentrations, it is still largely overestimated by the model, indicating the overestimations of SO2 concentrations in the North China Plain (NCP) are mostly due to errors in SO2 emission inventory. 相似文献
994.
替代脊椎动物进行化学物质和污染物危害评估的方法已成为越来越重要的需求。现在首先要考虑的是当启动一个脊椎动物生态毒性测试,必须确保不必要的脊椎动物生物的使用尽可能最小化。对于一些监管目的,脊椎动物的使用对环境风险评估(ERA)已经被禁止,而在其他情况下生物测试的数量已经大大减少了,或者测试程序严格精简了。然而,想要获得能够完全替代脊椎动物提供环境危害数据的方法仍有很长的路要走。动物替代品的发展不仅仅是基于道德的考虑,也可以降低执行脊椎动物生态毒性测试的成本以及在某些情况下能够提供更好的信息旨在改进环境风险评估。本文集中综述了在过去的几十年里生态毒性评估替代方法所发生的重大的进展。
精选自Adam Lillicrap, Scott Belanger, Natalie Burden, David Du Pasquier, Michelle R. Embry, Marlies Halder, Mark A. Lampi, Lucy Lee, Teresa Norberg-King, Barnett A. Rattner, Kristin Schirmer, Paul Thomas. Alternative approaches to vertebrate ecotoxicity tests in the 21st century: a review of developments over the last two decades and current status. Environmental Toxicology and Chemistry: Volume 35, Issue 11, pages 2637–2646, November 2016.
DOI: 10.1002/etc.3603
详情请见http://onlinelibrary.wiley.com/doi/10.1002/etc.3603/full 相似文献
995.
In mammals, the chemical profiles of individuals are complex and variable mixtures, and animals perceive information based on variation in the overall quality of these mixtures. A variety of compounds potentially involved in chemical communication have been characterized in the urine of different felid species, but little is known about the information content of felid scent marks. In this study, we investigated whether chemical composition of Eurasian lynx Lynx lynx urine was related to sex, reproductive state, and individual identity. We further analysed if elemental sulphur in lynx urine could serve as a dietary cue or as an indicator for the freshness of a scent mark. We collected urine from captive and wild Eurasian lynx, and analysed volatile constituents of urine by means of solid phase microextraction and gas chromatography-mass spectrometry. Our results show that lynx scent profiles contain sex-specific information on reproductive state, as well as individual identity cues. Urine marks are, therefore, well-suited to fulfil a role in reproductive behaviour and social organisation of wild lynx populations. Relative sulphur content was unrelated to time since last feeding, but decreased with age of the urine sample. The influence of diet and body condition on scent profiles should be further investigated by means of experimental studies, and may shed more light on the messages encoded in carnivore scent-marks. 相似文献
996.
997.
998.
999.
1000.