全文获取类型
收费全文 | 5137篇 |
免费 | 224篇 |
国内免费 | 729篇 |
专业分类
安全科学 | 266篇 |
废物处理 | 267篇 |
环保管理 | 448篇 |
综合类 | 1795篇 |
基础理论 | 1083篇 |
环境理论 | 2篇 |
污染及防治 | 1517篇 |
评价与监测 | 362篇 |
社会与环境 | 287篇 |
灾害及防治 | 63篇 |
出版年
2024年 | 19篇 |
2023年 | 69篇 |
2022年 | 222篇 |
2021年 | 183篇 |
2020年 | 170篇 |
2019年 | 148篇 |
2018年 | 230篇 |
2017年 | 170篇 |
2016年 | 181篇 |
2015年 | 201篇 |
2014年 | 203篇 |
2013年 | 426篇 |
2012年 | 237篇 |
2011年 | 289篇 |
2010年 | 245篇 |
2009年 | 255篇 |
2008年 | 251篇 |
2007年 | 274篇 |
2006年 | 216篇 |
2005年 | 188篇 |
2004年 | 209篇 |
2003年 | 191篇 |
2002年 | 164篇 |
2001年 | 301篇 |
2000年 | 185篇 |
1999年 | 86篇 |
1998年 | 59篇 |
1997年 | 58篇 |
1996年 | 49篇 |
1995年 | 53篇 |
1994年 | 52篇 |
1993年 | 48篇 |
1992年 | 37篇 |
1991年 | 43篇 |
1990年 | 30篇 |
1989年 | 37篇 |
1988年 | 22篇 |
1987年 | 23篇 |
1986年 | 20篇 |
1985年 | 18篇 |
1984年 | 21篇 |
1983年 | 23篇 |
1982年 | 23篇 |
1981年 | 17篇 |
1980年 | 12篇 |
1979年 | 14篇 |
1978年 | 12篇 |
1975年 | 13篇 |
1973年 | 9篇 |
1972年 | 10篇 |
排序方式: 共有6090条查询结果,搜索用时 250 毫秒
91.
92.
93.
关于环境自动监测的系统设计和方案探讨 总被引:7,自引:0,他引:7
根据上海市环境监测的现状,分别从大气环境、污染源排放、水和废水监测等方面提出了进一步开展自动监测的设想和网络优化设计,并探讨了有关管理措施。 相似文献
94.
Wu Jin Wang Anpu Huang Yanchu Ma ciguang Y. Ii S. Daishim K. Furuy T. Kikuchi H. Matsushit K. Tanabe 《环境科学学报(英文版)》1990,2(1):27-39
A study has been made on elements organic constituents, TSP, SO2,NO2 of atmospheric pollutants in Beijing. 17 elements, and some PAHs, e. g. B(a)P, B(b, j, k)P, and B(g, h, i)P, in airborne particles by X-ray fluorescence spectroscopy and HPLC, GC/MS, have been determined respectively. It has been shown that the elements Pb, Zn, S and Cu were more enriched in fine particles and different valence states of sulfur at various sites. It was found that the concentrations of S6+ and S2-were more than 85% and less than 15% of the total sulfur respectively. Concentrations of major PAHs and sulfur-containing compounds increased in winter and in urban area. High values for Pb and Zn in city, Fe and Mn at industrial area and Cu, Al rural sites were obtained respectively. This implies the functions of different elemental sources of various sites. Thus, elements can be from distingushed anthropogenic and natural sources.The main contribution of SO2 was found of to have same seasonal variation as the anthropogenic el 相似文献
95.
扬子地体上石炭统船山组内核形石极为丰富,按照内部结构和构造可分五种纹层类型、二种壳层构造和四种核心结构。核形石并非过去所认为的单一的“葛万藻核形石”,而可以根据形态和壳层中的生物组合划分为十种基本类型,其沉积环境有滩、潮下低能带和泻湖等。 石炭纪晚期,由于全球的气候发生强烈分异,从而在低纬度地区产生大量分泌粘液的缠绕生物(藻类为主),核形石就是由这种缠绕生物捕集沉积质点围绕核心而成,其形成过程有四个阶段—核心形成阶段,壳层形成阶段、沉积搬运阶段和成岩后生阶段。 在成岩后生阶段,核形石岩可以产生大量的核间和核内溶孔,这对于油气、矿液的储集和运移是十分有利的。 相似文献
96.
系统的探讨了区内白垩纪地层的划分与沉积相特征,深入研究了陆相地层的层序发育特征。指出,无论冲积扇、河流、三角洲或湖泊沉积的陆相地层层序均受地层基准面控制。地层基准面穿越旋回控制着陆相环境重大层序分布。根据不同时间间隔的基准面穿越旋回序次,将陆相层序划分为盆地充填层序、构造层序、层序、亚层序及小层序五个级别。每个层序根据基准面波动可划分为基准面上升沉积体系域和基准面下降沉积体系域,并可根据亚层序组的叠置特征进一步细分。根据上述陆相地层层序划分原理,作者将研究区白垩纪陆相地层划分为三个构造层序,并初步将葛村组划分为五个、浦口组四个、赤山组三个和泰州组三个沉积层序。 相似文献
97.
The application of ultrasonic-electrolysis process for the removal of copper is studied.In the ultrasonic field cavitation acts as jets and agitates the solution and breaks the barrier layer between the cathode surface and the bulk of the solution.Thus increases metal deposition on the cathode surface.The results show that an ultrasonic field is successful for the removal of low copper concentrations in solution. 相似文献
98.
Zhang YJ Bryan ND Livens FR Jones MN 《Environmental pollution (Barking, Essex : 1987)》1997,96(3):361-367
The interactions of a range of actinide elements (Th, U, Np, Pu, Am) with humic substances from the Needle's Eye natural analogue site were studied by gel permeation chromatography. Bulk humic substances were isolated by ammonia extraction, followed by dialysis against distilled water and freeze-drying. The gel permeation results suggest that Needle's Eye humic substances can be fractionated into three incompletely resolved fractions with average molecular weights determined by analytical ultracentrifugation around 49 000 for Fraction 1, around 14 700 for Fraction 2 and around 8000 for Fraction 3. Although there are significant differences between the organic matter elution patterns in individual gel permeation experiments, presumably due to differences in column packing, these are much smaller than the differences between metal ions. The uranium that is naturally present in these humic substances is largely bound in the late-eluting fraction. Spikes of the early actinides, including Np and Pu in controlled valency states, have been added to the humic substances, and gel permeation of the spiked humic substances shows that the three humic fractions vary greatly in their effectiveness and selectivity as ligands for early actinides. 相似文献
99.
The perturbant effects of four Triton adjuvants, namely Triton X-15, X-35, X-100, and X-114 (alkyl aryl polyether alcohols), on some of the biochemical determinants of membrane integrity were determined under laboratory conditions. Two of these, Triton X-100 and X-114, are currently being assessed as emulsifiers for use in fenitrothion insecticidal formulations. Lemna minor L. plants were exposed to 40 microM (10-25 microg ml(-1) in 965 microg mg(-1) Dowanol (tripropylene glycol methyl ether) carrier solvent) adjuvant for a treatment time period of two weeks. A decrease in the contents of the total phospholipids and a concomitant increase in the contents of the galactolipids were found. No change was observed in the total lipid content. An unsaturation occurred in the fatty acids of the total lipids, phospholipids, and monogalactosyl diacylglycerides. This accounted for a significant decrease in palmitic and stearic acids and a concomitant increase in oleic, linoleic, and linolenic acids when these are compared with the fatty acids in the nontreated control sets. The fatty-acid profile of the digalactosyl diacylglycerides, however, differed only slightly from controls. Membrane-fatty-acid unsaturation suggests the possibility of a desaturase enzyme's being induced by these adjuvants. 相似文献
100.