全文获取类型
收费全文 | 6640篇 |
免费 | 256篇 |
国内免费 | 1341篇 |
专业分类
安全科学 | 338篇 |
废物处理 | 404篇 |
环保管理 | 537篇 |
综合类 | 2543篇 |
基础理论 | 1342篇 |
环境理论 | 4篇 |
污染及防治 | 2167篇 |
评价与监测 | 394篇 |
社会与环境 | 350篇 |
灾害及防治 | 158篇 |
出版年
2024年 | 11篇 |
2023年 | 92篇 |
2022年 | 253篇 |
2021年 | 233篇 |
2020年 | 176篇 |
2019年 | 133篇 |
2018年 | 269篇 |
2017年 | 213篇 |
2016年 | 249篇 |
2015年 | 276篇 |
2014年 | 379篇 |
2013年 | 599篇 |
2012年 | 371篇 |
2011年 | 456篇 |
2010年 | 344篇 |
2009年 | 357篇 |
2008年 | 398篇 |
2007年 | 342篇 |
2006年 | 326篇 |
2005年 | 263篇 |
2004年 | 230篇 |
2003年 | 243篇 |
2002年 | 193篇 |
2001年 | 319篇 |
2000年 | 244篇 |
1999年 | 157篇 |
1998年 | 127篇 |
1997年 | 123篇 |
1996年 | 105篇 |
1995年 | 97篇 |
1994年 | 86篇 |
1993年 | 73篇 |
1992年 | 73篇 |
1991年 | 48篇 |
1990年 | 35篇 |
1989年 | 38篇 |
1988年 | 28篇 |
1987年 | 20篇 |
1986年 | 19篇 |
1985年 | 16篇 |
1984年 | 21篇 |
1983年 | 22篇 |
1982年 | 23篇 |
1981年 | 17篇 |
1980年 | 11篇 |
1979年 | 13篇 |
1978年 | 12篇 |
1975年 | 12篇 |
1973年 | 9篇 |
1972年 | 10篇 |
排序方式: 共有8237条查询结果,搜索用时 718 毫秒
161.
农药杀虫单的稻田流失规律研究 总被引:2,自引:0,他引:2
通过测坑、人工降雨等手段,对水溶性农药杀虫单的稻田消解动态、渗漏流失和径流流失等进行了研究。结果表明,(1)无水稻时,杀虫单在稻田水中消解的半衰期为0.76d;分蘖初期,杀虫单在稻田水中降解的半衰期为1.02d;平均为0.89d。(2)杀虫单的渗漏流失量在用药后8d内可达总用药量的7%—10%,平均为8.48%。(3)极端情况下,用药当天如果遇暴雨(50mm雨量),杀虫单的径流流失量将达到用药量的30%左右。杀虫单的渗漏损失不可避免,故其流失控制应从径流损失着手,尽量避免在可能有暴雨的当天或雨前1—2d用药。 相似文献
162.
介绍了我国水污染方面的情况、水污染治理的常用技术及基本工艺流程、水治理技术发展的新趋势和几种水处理的新技术。对这些新技术的基本原理、研究方向与前景作了阐述。 相似文献
163.
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
164.
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
165.
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
166.
167.
168.
J. Y. Kim M.-C. Shin J.-R. Park K. Nam 《Journal of Material Cycles and Waste Management》2003,5(1):0055-0062
The effect of the soil solids concentration in batch tests on the measured values of the partition coefficient (K
p) of organic pollutants in landfill liner-soil material was investigated. Since this study was based on the results of batch
and column tests conducted independently, there were limitations to the conclusions derived. The organic compounds tested
were benzene, methylene chloride, toluene, trichloroethylene, and p-xylene. The results of this study showed that as soil solids concentrations increased, the measured K
p values of these organic compounds strongly decreased. The observed values of K
p stabilized when the soil solids concentration was above a certain value. Typical K
p values obtained from batch tests conducted under high soil solids concentrations were close to those obtained from column
tests. It was concluded that the K
p values of organic compounds measured under low soil solids concentrations, i.e., less than 100 g/l, may not correctly simulate
the field situation. Consequently, the values of K
p obtained with low soil solids concentrations can result in an overestimation of the retardation factor of the landfill liner
material.
Received: March 14, 2002 / Accepted: August 25, 2002 相似文献
169.
170.
232名微机操作人员的慢性肌肉骨骼损伤表现为肩、颈、下背的酸痛和肩疲劳,与对照组比差异显著。手、腕及上肢的慢性损伤虽较对照组高,但无统计学意义。这与他们的击键次数相对较少(每日10000次左右),但需长期间保持低头及向前弯腰的坐位姿势及工作台面太高等因素有关 相似文献