全文获取类型
收费全文 | 779篇 |
免费 | 6篇 |
国内免费 | 18篇 |
专业分类
安全科学 | 14篇 |
废物处理 | 8篇 |
环保管理 | 46篇 |
综合类 | 322篇 |
基础理论 | 195篇 |
环境理论 | 2篇 |
污染及防治 | 162篇 |
评价与监测 | 29篇 |
社会与环境 | 24篇 |
灾害及防治 | 1篇 |
出版年
2018年 | 10篇 |
2017年 | 13篇 |
2016年 | 16篇 |
2015年 | 17篇 |
2014年 | 12篇 |
2013年 | 35篇 |
2012年 | 27篇 |
2011年 | 33篇 |
2010年 | 22篇 |
2009年 | 26篇 |
2008年 | 25篇 |
2007年 | 27篇 |
2006年 | 39篇 |
2005年 | 25篇 |
2004年 | 15篇 |
2003年 | 21篇 |
2002年 | 20篇 |
2001年 | 12篇 |
2000年 | 8篇 |
1999年 | 27篇 |
1998年 | 13篇 |
1997年 | 11篇 |
1996年 | 14篇 |
1995年 | 7篇 |
1994年 | 13篇 |
1993年 | 8篇 |
1991年 | 6篇 |
1989年 | 7篇 |
1988年 | 7篇 |
1987年 | 9篇 |
1985年 | 10篇 |
1983年 | 8篇 |
1970年 | 6篇 |
1967年 | 8篇 |
1966年 | 9篇 |
1965年 | 10篇 |
1964年 | 14篇 |
1963年 | 10篇 |
1962年 | 9篇 |
1961年 | 8篇 |
1960年 | 9篇 |
1958年 | 7篇 |
1957年 | 9篇 |
1956年 | 7篇 |
1955年 | 8篇 |
1954年 | 11篇 |
1953年 | 8篇 |
1952年 | 5篇 |
1939年 | 6篇 |
1931年 | 5篇 |
排序方式: 共有803条查询结果,搜索用时 0 毫秒
801.
Changes in microbial community composition and activity were related to geochemical conditions favoring arsenic sequestration in sediments collected from the urban, arsenic-contaminated Upper Mystic Lake. After amendment with nitrate, >94% total soluble arsenic is sequestered by Fe(III)-(oxy)hydroxides generated in live sediments. Of this sequestered arsenic, >75% existed as As(III), indicating As redox state alone is not responsible for changes in mobility. Arsenic sequestration was concurrent with the microbial respiration of nitrate as indicated by steady state hydrogen concentration and the presence of organisms similar to nitrate-reducing, iron-oxidizing bacteria belonging to the genus Dechloromonas in 16S rDNA clone libraries. 相似文献
802.
Klaus Zuberbühler 《Behavioral ecology and sociobiology》2001,50(5):414-422
One of the most prominent behavioural features of many forest primates are the loud calls given by the adult males. Early observational studies repeatedly postulated that these calls function in intragroup spacing or intergroup avoidance. More recent field experiments with Diana monkeys (Cercopithecus diana) of Taï Forest, Ivory Coast, have clearly shown that loud male calls function as predator alarm calls because calls reliably (1) label different predator classes and (2) convey semantic information about the predator type present. Here, I test the alarm call hypothesis another primate, the Campbell's monkey (C. campbelli). Like Diana monkeys, male Campbell's monkeys produce conspicuous loud calls to crowned hawk eagles (Stephanoaetus coronatus) and leopards (Panthera pardus), two of their main predators. Playback experiments showed that monkeys responded to the predator category represented by the different playback stimuli, regardless of whether they consisted of (1) vocalisations of the actual predators (crowned hawk eagle shrieks or leopard growls), (2) alarm calls to crowned hawk eagles or leopards given by other male Campbell's monkeys or (3) alarm calls to crowned hawk eagles or leopards given by sympatric male Diana monkeys. These experiments provide further evidence that non-human primates have evolved the cognitive capacity to produce and respond to referential labels for external events. 相似文献
803.
Klaus Reinhardt 《Behavioral ecology and sociobiology》2001,50(6):503-510
Models for the evolution of ejaculate expenditure predict that ejaculate size (ES) depends on male body condition, on female fecundity, or on the risk of sperm competition. These ideas were tested in the grasshopper Chorthippus parallelus. ES ranged over four orders of magnitude, around a mean of 442,000 sperm. ES was independent of male body size and female fecundity. None of the male condition parameters - age, degree of parasitism, macropterism score (a measurement of competitive energy allocation to other sources), and the mass-femur length residuals - explained variation in ES. As expected in species where females are cyclically non-receptive after mating, male-male encounters before copulation were a more reliable indicator of the risk of sperm competition than the number of males present during copulation. In particular, the summative number of male-male encounters rather than the male-male encounter frequency was a significant predictor of ES variation (24.9%). 相似文献