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   1149篇
  免费   8篇
  国内免费   28篇
安全科学   11篇
废物处理   56篇
环保管理   147篇
综合类   98篇
基础理论   196篇
污染及防治   405篇
评价与监测   209篇
社会与环境   61篇
灾害及防治   2篇
  2023年   33篇
  2022年   75篇
  2021年   60篇
  2020年   12篇
  2019年   26篇
  2018年   38篇
  2017年   34篇
  2016年   53篇
  2015年   27篇
  2014年   49篇
  2013年   146篇
  2012年   55篇
  2011年   63篇
  2010年   50篇
  2009年   47篇
  2008年   64篇
  2007年   43篇
  2006年   43篇
  2005年   34篇
  2004年   31篇
  2003年   29篇
  2002年   20篇
  2001年   17篇
  2000年   9篇
  1999年   10篇
  1998年   4篇
  1997年   7篇
  1996年   6篇
  1993年   5篇
  1992年   7篇
  1991年   8篇
  1990年   3篇
  1989年   5篇
  1988年   3篇
  1987年   8篇
  1986年   4篇
  1984年   2篇
  1982年   5篇
  1980年   2篇
  1978年   4篇
  1976年   6篇
  1975年   4篇
  1974年   2篇
  1972年   3篇
  1969年   5篇
  1968年   4篇
  1965年   2篇
  1959年   2篇
  1957年   3篇
  1956年   2篇
排序方式: 共有1185条查询结果,搜索用时 343 毫秒
331.
This study evaluates the possibility of using contaminated soil by treated tannery wastewater and the use of tannery sludge in agriculture. The plants of Vigna radiata var. PDM 54 grown on contaminated soil and irrigated with ground water have not shown the translocation of toxic metal (Cr) in the upper part. The biomass of the plant increased when irrigated with treated tannery wastewater compared to ground water, whereas no significant change was observed in chlorophyll and protein contents. In both the varieties (var. PDM 54 and var. NM 1) of V. radiata grown on tannery sludge amendments, the growth parameters exhibited a pronounced positive growth response up to 35% tannery sludge amendments compared with the plants grown on garden soil. Despite the Cr accumulation at lower amendments, no toxicity symptoms were observed in both the varieties of the plants. Higher amendments affected various growth parameters, NR activity, and carbohydrate content of the plants. The results suggest that the plants of V. radiata (var. PDM 54) may be grown on contaminated soil or lower sludge amendments and irrigated with ground water. No translocation of toxic metal Cr was found in the seeds of the plants grown in up to 25% tannery sludge. However, periodical monitoring is required before the consumption of seeds. Overall, the results showed that plant growth patterns were influenced to some extent by the level of soil contamination and the water used for irrigation.  相似文献   
332.
Molasses spent wash from cane-molasses based distilleries contains a brown coloured recalcitrantpolymer melanoidin, which if disposed untreated poses a great threat to environment. Microbial decolorization and chemical oxygen demand (COD) reduction was found to be dependent on specific carbon and nitrogen source. Under optimal condition of pH, carbon and nitrogen concentration for each treatment, it was found that Bacillus sp isolated from soil was capable of removing COD (85. 35%) and colour (81.10%) from distillery waste to the maximum extent after 9 days atpH 7 in the medium containing 0.5% peptone, 2% glucose and 10% (v/v), followed by Phanerochaete chrysosporium and lowest reduction was obtained by using native microbial consortium.  相似文献   
333.
Relative susceptibility of three important mosquito vector larvae viz., Anopheles stephensi, Aedes aegypti and Culex quinquefasciatus, prevalent in the arid region was determined against four organophosphates (malathion, fenitrothion, fenthion, temephos) and three synthetic pyrethroid (alphamethrin, deltamethrin and fanvalerate) compounds. Studies were carried out on late 3rd or early 4th instar larvae of these species using standard WHO technique. Based on concentration mortality data LC50 and LC90 values along with their fiducial limits, regression equation, chi-square (chi2)/heterogeneity of the response have been determined by log probit regression analysis. LC50 values as observed for the above seven insecticides were 0.8097, 0.0398. 0.0432, 0.0035, 0.0025, 0.0092, 0.1006; 1.2370, 0.0531, 0.0655, 0.0076, 0.00004, 0.00004, 0.0046 and 1.4980, 0.0719, 0.0817, 0.0056, 0.00021, 0.00073, 0.0112 mg/l for the above three mosquito species respectively Among the four organophosphates tested temephos was the most effective followed by fenitrothion, fenthion and malathion. In general, Anopheles was found more susceptible as compared to the other two culicines to the above four compounds. The results also showed that larvae of Ae. aegypti were most susceptible followed by Cx. quinquefasciatus and An. stephensi to all the three pyrethroids tested. Among the three compounds tested alphamethrin was found to be the most toxic followed by deltamethrin while fanvalerate was the least toxic. The study would be of great importance while planning use of these insecticides for the control of different vector species in this area.  相似文献   
334.
Correlation coefficient analysis conducted on 22 triticale x bread wheat derivatives along with six checks to select true- breeding derivative(s) for future hybridization programme with tolerance to drought and cold stress conditions as well as better quality traits revealed significant correlation of grain yield with spikelets per spike, biological yield, harvest index, leaf area index. Interestingly, the grain yield and drought susceptibility index showed no association. However, with cold tolerance it showed significant positive correlation indicating the desirability of certain plant traits under cold stress. The grain yield exhibited no association with quality traits which might assist in the predictability of high yielding varieties with high protein, total sugars, reducing sugars and non-reducing sugars. Path coefficient analysis revealed that biological yield had the highest positive direct effect on grain yield followed by harvest index, specific leaf weight, stomatal number, 1000 grain weight, stomatal size, spikelets per spike and days to heading. Therefore, indirect selection for these plant traits in order should be exercised in selecting drought tolerant genotypes. Two genotypes (RL-124-2P2 and RL 111P2) were found to be drought and cold tolerant with high grain yield, spikes per plant, spikelets per spike and leaf area index.  相似文献   
335.
The catfish, H. fossilis were exposed to endosulfan for 30 days at sub-lethal concentration (0.002 ppm) during different phases of its annual reproductive cycle. Its impact on total (TP) and different phospholipids- phosphatidylcholine (PC), phosphatidylserine (PS), phosphatdylinositol (Pl) and phosphatidylethanolamine (PE) were measured in liver plasma and ovary. On pesticide exposure, during preparatory phase, the hepatic TP PC and PE were declined. The plasma levels of TP, PC and PS were declined with the elevation of PE whereas in ovary only PC was lowered after endosulfan exposure. During pre-spawning phase, the hepatic TP, PC and PE declined in liver plasma and ovary after endosulfan exposure. During spawning phase, only plasma and ovarian phospholipids showed decrease in their levels following endosulfan exposure. In the post-spawning phase, endosulfan elevated the levels of TP, PC and PS in ovary but had no effect on their levels in liver and plasma. During resting phase, the TP, PC and Pl were found to be decreasing its levels. Thus it appears that this pesticide interfere with phospholipids metabolism during annual reproductive cycle of this species.  相似文献   
336.
337.
338.
Environmental Science and Pollution Research - The impacts of vegetation cover changes (VCCs) and land use land cover changes (LULCCs) on climate variabilities need to be addressed while...  相似文献   
339.
Environmental Science and Pollution Research - Coronavirus disease 2019 (COVID-19) has emerged as a significant public health emergency in recent times. It is a respiratory illness caused by the...  相似文献   
340.
Environmental Science and Pollution Research - The total number of inhabitants on the Earth is estimated to cross a record number of 9 × 103 million by 2050 that present a unique challenge to...  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