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   253篇
  免费   21篇
  国内免费   43篇
安全科学   24篇
废物处理   20篇
环保管理   13篇
综合类   152篇
基础理论   58篇
污染及防治   27篇
评价与监测   11篇
社会与环境   9篇
灾害及防治   3篇
  2024年   1篇
  2023年   4篇
  2022年   3篇
  2021年   6篇
  2020年   7篇
  2019年   8篇
  2018年   8篇
  2017年   7篇
  2016年   5篇
  2015年   6篇
  2014年   4篇
  2013年   29篇
  2012年   12篇
  2011年   11篇
  2010年   10篇
  2009年   10篇
  2008年   11篇
  2007年   14篇
  2006年   10篇
  2005年   19篇
  2004年   20篇
  2003年   11篇
  2002年   14篇
  2001年   18篇
  2000年   11篇
  1999年   5篇
  1998年   2篇
  1997年   3篇
  1996年   6篇
  1995年   5篇
  1994年   5篇
  1993年   2篇
  1992年   4篇
  1991年   4篇
  1990年   2篇
  1989年   2篇
  1988年   3篇
  1987年   3篇
  1986年   2篇
  1985年   5篇
  1984年   2篇
  1982年   2篇
  1981年   1篇
排序方式: 共有317条查询结果,搜索用时 31 毫秒
91.
We described a new case of mosaic isochromosome 20q revealed by amniocentesis. The propositus presented with craniofacial dysmorphism, clubfeet, and vertebral abnormalities. A 46,XX,i(20)(q10)[14]/46,XX[1] karyotype was confirmed by FISH on cultured cells. The pregnancy was terminated. From review of literature, fetus with mosaic isochromosome 20q identified on amniocentesis are most likely to be phenotypically and cytogenetically normal after birth. So we performed CGH and array-CGH to exclude another possible imbalance. We discuss here the possible relation between this chromosomal abnormality and the abnormal phenotype. Copyright © 2005 John Wiley & Sons, Ltd.  相似文献   
92.
Measurements of flammability and explosion parameters for dust/air mixtures require uniform dispersion of the dust cloud inside the test vessel. In a previous work, we showed that, in the standard 20 L sphere, the dust injection system does not allow generation of a uniform cloud, but rather high gradients of dust concentration are established. In this work, we used a previously validated three-dimensional CFD model to simulate the dust dispersion inside the 20 L sphere at different dust nominal concentrations (and fixed dust diameter). Results of numerical simulations have shown that, as the dust nominal concentration is increased, sedimentation prevails and, thus, when ignition is provided, the dust is mainly concentrated at the vessel walls.  相似文献   
93.
类黑精是一种高分子难降解色素污染物质,在糖蜜酒精废水中大量存在.选取在前期研究中对糖蜜酒精废水具有较好脱色作用的黄曲霉(Aspergillus flavus)A5p1(保藏号CGMCC.4292),以合成的类黑精为对象研究脱色机理,试图为实际废水的生物脱色提供理论基础.结果显示,此菌株对合成类黑精具有生物吸附和生物降解的双重作用,以后者为主,最高脱色率可达65%.相较于漆酶、依赖/不依赖于锰的过氧化物酶等常规氧化脱色酶,此菌株中的产过氧化氢酶对脱色起主要作用,而且脱色过程中作为产过氧化氢酶之一的葡萄糖氧化酶与类黑精脱色率之间存在着一定的正相关性.添加葡萄糖氧化酶激活剂和抑制剂进行验证,发现葡萄糖氧化酶酶活力、过氧化氢产量和脱色率三者之间呈相关性变化.初步推测,葡萄糖氧化酶是黄曲霉A5p1生物降解脱色类黑精的关键酶之一.  相似文献   
94.
95.
96.
In 1980, the World Health Organization (Regional Office for Europe) invited The Centre for Environmental Management and Planning (CEMP) to organize a two-week training course on Environmental Impact Assessment (EIA) to provide a comprehensive introduction to EIA with emphasis on methods and techniques for impact identification, prediction and assessment. Not suprisingly the topic of environmental health impact assessment was to be a major focus. Since 1980, the course has been held each year at the University of Aberdeen. An analysis of participation in the course during its first five years yields several impressions about the success of this training effort and the ways in which it might be improved.  相似文献   
97.
The article presents the results of chemical andmicrobiological measurements of the water quality in theBuko Blato reservoir, the largest in Europe, in the period 1989 to 1998.The aim was to observe possiblechanges in water quality during the past decade and itsinfluence on the downstream section of the Cetina River andits numerous tributaries and reservoirs, where there are twolarge regional water supply systems. This reservoir wasbuilt in order to exploit the high hydro-electric potentialof small streamflows in the karst fields of south-westernBosnia. It has strongly influenced the hydrologicconditions of the downstream section of the Cetina River.Buko Blato is a relatively shallow reservoir with the meandepth of 5 m. It covers an area of 57 km2. The waterexchange in the reservoir is slow, occurring from one toseveral years. When the water inflow exceeds the hydroelectric plant demands the excess water is delivered by a reversible channel and pre-pumped into the Buko Blato reservoir. The total and carbonate water hardness in thereservoir is lower than in the Cetina River and in typicalkarst streamflows, since the water in this reservoir comesmainly from surface sources including numerous springs withhigh capacity oscillations, torrents and rainfall.Measurements, carried out during the past years, showed asignificant increase in nitrate content as well as in thecoli bacteria and a less significant increase in totalphosphorus content. The water quality was evaluated asmezotrophic according to the total phosphorus content basedon the Carlson index of trophic level, a lower quality thanin the Perua reservoir, upstream on the Cetina River. Thelatter contains a smaller phosphorus content and wasclassed between oligotrophic and mezotrophic. According tothese data, employing the Vollenweider equation, the totalphosphorus content in this water should not exceed the meanof 20 mg m-3 P. The results indicate that the water inthe Buko Blato reservoir did not deteriorate the waterquality on the downstream section of the Cetina River.  相似文献   
98.
三丁基锡对正常人胚胎羊膜细胞凋亡相关蛋白表达的影响   总被引:3,自引:0,他引:3  
首次采用蛋白质印迹法研究三丁基锡(tributyltin,TBT)对正常人胚胎羊膜细胞FL(human amniotic cells)的Bcl-2、Bax和p53表达的影响.结果显示,在0、1、2、3、4μmol·L-1三丁基锡下作用2 h后,FL细胞的Bax蛋白表达量随浓度增加逐渐升高,Bcl-2蛋白表达量仅在3、4μmol·L-1浓度组相比于对照组明显下降.作为凋亡是否发生的决定因素,Bax/Bcl-2比值在三丁基锡高浓度组(3、4μmol·L-1)相比于对照有显著升高;而p53蛋白表达量没有明显变化.研究表明,Bcl-2和Bax参与了TBT诱导的细胞凋亡.  相似文献   
99.
电化学法同时测定水样中的间硝基酚和对硝基酚   总被引:5,自引:0,他引:5  
郝俊英  任守信 《环境化学》2004,23(2):213-217
用微分脉冲伏安法同时测定了水样中含间硝基酚和对硝基酚的混合体系 ,在 0 1mol·l- 1 乙二胺 0 5mol·l- 1 氯化铵 (pH =8 5 0 )底液中于 - 0 5 0V和 - 0 69V (vsAg/AgCl)处出现两个灵敏度高且互不干扰的吸附波 .间硝基酚和对硝基酚分别在 4 0× 1 0 - 7— 8 0×1 0 - 5mol·l- 1 和 2 0× 1 0 - 7— 4 0× 1 0 - 5mol·l- 1 范围内与峰电流ip 呈良好的线性关系 .检测限分别为 8 0× 1 0 - 8mol·l- 1 和 6 0× 1 0 - 8mol·l- 1 .本法可用于环境废水中微量间硝基酚和对硝基酚的同时测定 .另外 ,对双组分体系的吸附性质和电极反应机理作了研究 .  相似文献   
100.
Wide distribution, stability and long persistence in the environment of dichlorodiphenyltrichloroethane (DDT), probably the best-known and most useful insecticide in the world, imposes the need for further examination of the effect of this chemical on human health and especially on the human genome. In this study, peripheral blood human lymphocytes from a healthy donor were exposed to 0.025 mg/L concentration of p,p′-DDT at different time periods (1, 2, 24 and 48 h). For the assessment of genotoxic effect, the new criteria for scoring micronucleus test and alkaline comet assay were used. Both methods showed that p,p′-DDT induces DNA damage in low concentration used in this research. Results of micronucleus test showed a statistically significant (p < 0.05) genotoxic effect of p,p′-DDT on human lymphocytes compared with corresponding control and a different exposure time. A comet assay also showed increased DNA damage caused in p,p′-DDT-exposed human lymphocytes than in corresponding control cells for the tail length. Results obtained by measuring the level of DNA migration and incidence of micronuclei (MN), nucleoplasmic bridges (NPBs) and nuclear buds (NBUDs) indicate the sensitivity of these tests and their application in detection of primary genome damage after long-term exposure to establish the effect of p,p′-DDT on human genome.  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