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   862篇
  免费   2篇
  国内免费   6篇
安全科学   9篇
废物处理   6篇
环保管理   23篇
综合类   512篇
基础理论   126篇
污染及防治   146篇
评价与监测   25篇
社会与环境   20篇
灾害及防治   3篇
  2018年   10篇
  2017年   11篇
  2015年   10篇
  2014年   12篇
  2013年   32篇
  2012年   15篇
  2011年   16篇
  2010年   22篇
  2009年   24篇
  2008年   24篇
  2007年   30篇
  2006年   16篇
  2004年   12篇
  2003年   12篇
  2002年   16篇
  2001年   12篇
  2000年   10篇
  1999年   22篇
  1996年   8篇
  1992年   8篇
  1979年   12篇
  1978年   14篇
  1969年   8篇
  1966年   16篇
  1965年   10篇
  1964年   16篇
  1963年   12篇
  1962年   9篇
  1961年   18篇
  1960年   9篇
  1958年   10篇
  1957年   9篇
  1956年   11篇
  1955年   11篇
  1954年   11篇
  1953年   9篇
  1952年   9篇
  1941年   10篇
  1940年   9篇
  1938年   7篇
  1937年   13篇
  1936年   11篇
  1935年   10篇
  1934年   11篇
  1933年   8篇
  1931年   10篇
  1929年   9篇
  1922年   8篇
  1921年   7篇
  1913年   7篇
排序方式: 共有870条查询结果,搜索用时 218 毫秒
311.
312.
313.
314.
315.
316.
317.
Domorganus oligochaetophilus n.sp., a new representative of the Cylindrolaiminae Micoletzky (1922) sensu De Coninck (1965) is described. The adults live as endo-parasites in the intestine of littoral oligochaetes (Lumbricillus lineatus O. F. Müller 1774) from the Kieler Bucht (western Baltic Sea). This is the first endo-parasitic record in marine invertebrates of the Nematoda Adenophorea. The new species is characterized morphologically by: 4 cephalic setae, a very small buccalcavity without any sclerotized structures, an esophagus, with 2 bulbs, an excretory pore located posterior to the esophagus, reflexed diorchic ovaria, outstretched diochic testes, and 1 vesicular pre-anal organ in the male. Observations on living specimens show that the parasites live free in the intestinal lumen or are fixed by their spinneret glands at the intestinal wall of their hosts. Their food consists apparently of particulate intestinal contents.  相似文献   
318.
319.
Sequential supercritical fluid (CO2) extraction (SSFE) was applied to eight historically contaminated soils from diverse sources with the aim to elucidate the sorption-desorption behavior of high molecular weight polycyclic aromatic hydrocarbons (PAHs). The method involved five extraction phases applying successively harsher conditions by increasing fluid temperature and density mobilizing target compounds from different soil particle sites. Two groups of soils were identified based on readily desorbing (available) PAH fractions obtained under mildest extraction conditions (e.g., readily desorbing fractions of fluoranthene and pyrene significantly varied between the soils ranging from <10 to >90%). Moreover, extraction behavior strongly correlated with molecular weight revealing decreasing available PAH fractions with increasing weight. Physicochemical soil parameters such as particle size distribution and organic dry mass were found to have no distinct effect on the sorption-desorption behavior of PAHs in the different soils. However, PAH profiles significantly correlated with readily available pollutant fractions; soils with relatively less mobile PAHs had higher proportions of five- and six-ring PAHs and vice versa. Eventually, biodegradability corresponded well with PAH recoveries under the two mildest extraction phases. However, a quantitative relationship was only established for soils with biodegradable PAHs. Out of eight soils, five showed no biodegradation including the four soils with the lowest fraction of readily desorbing PAHs. Only one soil (which was found to be highly toxic to Vibrio fischeri) did not match the overall pattern showing no PAH biodegradability but large fractions of highly mobile PAHs, concluding that mass transfer limitations may only be one of many factors governing biodegradability of PAHs.  相似文献   
320.
Cheng SH  Chan KW  Chan PK  So CH  Lam PK  Wu RS 《Chemosphere》2004,55(10):1387-1394
The effect of cadmium on stage II naupliar larvae of barnacle (Balanus amphitrite Darwin) was investigated. Barnacle larvae were exposed to 0-15 microM CdCl(2) for 24 h. Apoptotic cells were stained by the terminal deoxyribonucleotidyl transferase mediated dUTP nick end labelling (TUNEL) method. Incidence of apoptosis, as measured by numbers of animals with ectopic pattern of apoptosis as well as numbers of apoptotic cells per animal, was assessed using confocal microscopy. An increase in incidence of apoptosis was observed in the experimental animals with an increase in cadmium concentration. Mortality increased, and motility decreased, when barnacle larvae were exposed to an increasing concentration of cadmium. The relationship between the occurrence of apoptosis and swimming behaviour was investigated in larvae exposed to 10 microM CdCl(2). Significant increases in apoptosis were detected in the non-motile and dead nauplii. This study suggested that whole-mount in situ TUNEL method may be used to study increased occurrence of apoptotic cells in crustacean larvae.  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