首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   1645篇
  免费   17篇
  国内免费   43篇
安全科学   22篇
废物处理   113篇
环保管理   160篇
综合类   141篇
基础理论   295篇
环境理论   2篇
污染及防治   560篇
评价与监测   300篇
社会与环境   108篇
灾害及防治   4篇
  2023年   59篇
  2022年   176篇
  2021年   117篇
  2020年   26篇
  2019年   46篇
  2018年   83篇
  2017年   92篇
  2016年   112篇
  2015年   47篇
  2014年   83篇
  2013年   180篇
  2012年   77篇
  2011年   89篇
  2010年   69篇
  2009年   58篇
  2008年   72篇
  2007年   54篇
  2006年   64篇
  2005年   34篇
  2004年   24篇
  2003年   20篇
  2002年   28篇
  2001年   8篇
  2000年   8篇
  1999年   5篇
  1998年   3篇
  1997年   2篇
  1996年   6篇
  1995年   2篇
  1994年   4篇
  1993年   3篇
  1992年   3篇
  1989年   4篇
  1988年   3篇
  1985年   2篇
  1984年   2篇
  1983年   4篇
  1982年   5篇
  1979年   2篇
  1969年   1篇
  1966年   1篇
  1965年   2篇
  1964年   2篇
  1962年   2篇
  1961年   4篇
  1958年   3篇
  1957年   3篇
  1956年   2篇
  1955年   4篇
  1953年   1篇
排序方式: 共有1705条查询结果,搜索用时 78 毫秒
741.
Environmental Science and Pollution Research - Himalaya, the highest mountain system in the world and house of important biodiversity hotspot, is sensitive to projected warming by climate change....  相似文献   
742.
Environmental Science and Pollution Research - Reduced sulfur compounds are a nuisance in coastal industries causing heavy economical as well as ecological loss. One such compound, hydrogen...  相似文献   
743.
Environmental Science and Pollution Research - Marine biofouling has gnawed both mobile and non-mobile marine structures since time immemorial, leading to the deterioration of designed operational...  相似文献   
744.
Environmental Science and Pollution Research - The megacities experience poor air quality frequently due to stronger anthropogenic emissions. India had one of the longest lockdowns in 2020 to curb...  相似文献   
745.
Environmental Science and Pollution Research - Heavy metals (HMs) have attracted global attention due to their toxicity, persistence, and accumulation in aquatic fish in the polluted water...  相似文献   
746.
Aspergillus was found as a dominant fungi to associate with brands of bindis. Among three potencies of four homeopathic drugs, Lycopodium 1M, Sulphur 1M, and Sepia 30 showed maximum inhibition zone of Aspergillus niger in inhibition zone technique. In poison food technique, Sepia 30M, Tellurium 30M, Sulphur 1M and Lycopodium 200 showed maximum percentage inhibition against A. niger  相似文献   
747.
Comparative toxicological studies of textile dye wastewater (untreated and treated) on a freshwater fish, Gambusia affinis, revealed a marked reduction in mortality and cytotoxic effects on RBCs, measured as reduction in their counts and percent changes in their shape (poikilocytosis) and variation in their size (anisocytosis)}, after subjecting them to both physicochemical and biological treatments. On comparing the data of mortality and the cytotoxic effects on RBCs, we found poikilocytosis is a better indicator for toxicity measurement of both untreated as well as treated wastewater, especially at their lowest concentrations where percent mortality was found to be either nil or lowerer than the percentage of poikilocytic RBCs. Although percent reduction in RBC counts and changes in their size (anisocytosis) indicated toxic effects of wastewaters, but EC5o values for RBC counts were usually higher than those for poikilocytosis and mortality, and non-calculable for anisocytosis suggesting their lesser sensitivity to pollutants. In view of these findings, we recommend monitoring of toxic effects of wastewaters during fish bioassay on both mortality and variation in RBC shape.  相似文献   
748.
Coontail (Ceratophyllum demersum L.) plants when exposed to various concentrations of Pb (1-100microM) for 1-7days, exhibited both phytotoxic and tolerance responses. The specific responses were function of concentration and duration. Plants accumulated 1748mugPbg(-1) dw after 7d which reflected its metal accumulation ability, however most of the metal (1222microgg(-1) dw, 70%) was accumulated after 1d exposure only. The toxic effect and oxidative stress caused by Pb were evident by the reduction in biomass and photosynthetic pigments and increase in malondialddehyde (MDA) content and electrical conductivity with increase in metal concentration and exposure duration. Morphological symptoms of senescence phenomena such as chlorosis and fragmentation of leaves were observed after 7d. The metal tolerance and detoxification strategy adopted by the plant was investigated with reference to antioxidant system and synthesis of phytochelatins. Protein and antioxidant enzymes viz., superoxide dismutase (SOD, EC 1.15.1.1), guaiacol peroxidase (GPX, EC 1.11.1.7) ascorbate peroxidase (APX, EC 1.11.1.11), catalase (CAT, EC 1.11.1.6) and glutathione reductase (GR, EC 1.6.4.2) showed induction at lower concentration and duration followed by decline. All enzymes except GPX showed maximum activity after 1d. An increase in cysteine, non-protein thiols (NP-SH) and glutathione (GSH) content was observed at moderate exposure conditions followed by decline. Phytochelatins (PC(2) and PC(3)) were synthesized to significant levels at 10 and 50microM Pb with concomitant decrease in GSH levels. Thus production of PCs seems important for the detoxification of metal, however it may lead to depletion of GSH and consequently oxidative stress. Results suggest that plants responded positively to moderate Pb concentrations and accumulated high amount of metal. Due to metal accumulation coupled with detoxification potential, the plant appears to have potential for its use as phytoremediator species in aquatic environments having moderate pollution of Pb.  相似文献   
749.
In the present study, we isolated three novel bacterial species, namely, Staphylococcus sp., Bacillus circulans-I, and Bacillus circulans-II, from contaminated soil collected from the premises of a pesticide manufacturing industry. Batch experiments were conducted using both mixed and pure cultures to assess their potential for the degradation of aqueous endosulfan in aerobic and facultative anaerobic condition. The influence of supplementary carbon (dextrose) source on endosulfan degradation was also examined. After four weeks of incubation, mixed bacterial culture was able to degrade 71.82 +/- 0.2% and 76.04 +/- 0.2% of endosulfan in aerobic and facultative anaerobic conditions, respectively, with an initial endosulfan concentration of 50 mg l(-1). Addition of dextrose to the system amplified the endosulfan degradation efficiency by 13.36 +/- 0.6% in aerobic system and 12.33 +/- 0.6% in facultative anaerobic system. Pure culture studies were carried out to quantify the degradation potential of these individual species. Among the three species, Staphylococcus sp. utilized more beta endosulfan compared to alpha endosulfan in facultative anaerobic system, whereas Bacillus circulans-I and Bacillus circulans-II utilized more alpha endosulfan compared to beta endosulfan in aerobic system. In any of these degradation studies no known intermediate metabolites of endosulfan were observed.  相似文献   
750.
Organochlorine pesticides are ubiquitous and persistent organic pollutants used widely throughout the world. Due to the extensive use in agriculture, organic environmental contaminants such as HCH, DDT along with other organochlorine pesticides are distributed globally by transport through air and water. The main aim of present study is to determine contamination levels of organochlorine pesticides in the ground water of Hyderabad City. Water samples were collected from 28 domestic well supplies of the city. For this study, random sampling technique was applied, all the samples were collected in high purity glass bottles and refrigerated at 4 degrees C until analysis. Solid Phase Extraction (SPE) is used for the extraction of organochlorine pesticide residues in water sample. The collected water samples were pre-filtered through a 0.45 microg glass fiber filter (Wattman GF/F) to remove particulate matter and were acidified with hydrochloric acid (6N) to pH 2.5. Methanol modifier (BDH, for pesticide residue analysis, 10 mL) was added to water sample for better extraction. SPE using pre-packed reversed phase octadecyl (C-18 bonded silica) contained in cartridges was used for sample preparation. Prior to the extraction, the C-18 bonded phase, which contains 500 mg of bonded phase, was washed with 20 mL methanol. The sample was mixed well and allowed to percolate through the cartridges with flow rate of 10-15 mL/min under vacuum. After sample extraction, suction continued for 15 min to dry the packing material and pesticides trapped in the C-18 bonded phases were eluted by passing 10 mL hexane and fraction was evaporated in a gentle steam of Nitrogen. In all samples pesticide residues were analyzed by GC (Chemito-8510) with Ni63 ECD detector. Helium was used as carrier gas and nitrogen was used as make up gas. The injection technique was split/split less. All the samples analyzed were found to be contaminated with four pesticides i.e. DDT, beta-Endosulfan, alpha-Endosulfan and Lindane. DDT was found to range between 0.15 and 0.19 microg L(-1), beta-Endosulfan ranges between 0.21 and 0.87 microg L(-1), alpha-Endosulfan ranges between 1.34 and 2.14 microg L(-1) and Lindane ranges between 0.68 and 1.38 microg L(-1) respectively. These concentrations of pesticides in the water samples were found to be above their respective Acceptable Daily Intake (ADI) values for Humans.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号