全文获取类型
收费全文 | 2764篇 |
免费 | 17篇 |
国内免费 | 35篇 |
专业分类
安全科学 | 75篇 |
废物处理 | 146篇 |
环保管理 | 274篇 |
综合类 | 491篇 |
基础理论 | 557篇 |
环境理论 | 2篇 |
污染及防治 | 816篇 |
评价与监测 | 251篇 |
社会与环境 | 184篇 |
灾害及防治 | 20篇 |
出版年
2023年 | 30篇 |
2022年 | 88篇 |
2021年 | 112篇 |
2020年 | 56篇 |
2019年 | 43篇 |
2018年 | 101篇 |
2017年 | 101篇 |
2016年 | 126篇 |
2015年 | 77篇 |
2014年 | 121篇 |
2013年 | 176篇 |
2012年 | 128篇 |
2011年 | 167篇 |
2010年 | 120篇 |
2009年 | 111篇 |
2008年 | 121篇 |
2007年 | 113篇 |
2006年 | 76篇 |
2005年 | 115篇 |
2004年 | 155篇 |
2003年 | 151篇 |
2002年 | 97篇 |
2001年 | 74篇 |
2000年 | 33篇 |
1999年 | 33篇 |
1998年 | 15篇 |
1997年 | 26篇 |
1996年 | 16篇 |
1995年 | 22篇 |
1994年 | 17篇 |
1993年 | 8篇 |
1992年 | 11篇 |
1991年 | 16篇 |
1990年 | 10篇 |
1989年 | 11篇 |
1988年 | 5篇 |
1987年 | 10篇 |
1986年 | 8篇 |
1985年 | 10篇 |
1984年 | 10篇 |
1983年 | 11篇 |
1982年 | 5篇 |
1981年 | 7篇 |
1979年 | 8篇 |
1977年 | 3篇 |
1975年 | 3篇 |
1970年 | 4篇 |
1966年 | 3篇 |
1964年 | 4篇 |
1961年 | 3篇 |
排序方式: 共有2816条查询结果,搜索用时 517 毫秒
931.
932.
933.
In this article, we review the virology, pathology, epidemiology and clinical spectrum of intrauterine human parvovirus B19 (B19V) infection, including intrauterine fetal death, non-immune hydrops fetalis, thrombocytopenia and neurological manifestations such as pediatric stroke and perivascular calcifications. In addition, we discuss the new insights into the neurodevelopmental outcome of intrauterine B19V infection. Current diagnosis and management of B19V infection is summarized, including a diagnostic and follow-up flowchart for practical clinical use. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
934.
935.
936.
937.
938.
The diet of the Humboldt penguin (Spheniscus humboldti) was examined and compared in two colonies in Chile. Field work was conducted on Pan de Azúcar Island in northern Chile in the breeding season 1998/1999 and on the Puñihuil Islands in southern Chile over two successive breeding seasons during 1997/1998 and 1998/1999. Penguin diet was studied by stomach-pumping birds and analysed by species composition, size and mass of prey. Fish were the dominant prey item at both sites, the contribution of cephalopods and crustaceans varying between sites. The fish prey consisted predominantly of school fish, but there were clear latitudinal differences in fish prey taken. Penguins in the northern colony consumed primarily garfish (Scomberesox saurus), while birds at the southern colony of Puñihuil fed primarily on anchovy (Engraulis ringens), Araucanian herring (Strangomera bentincki) and silverside (Odontesthes regia). The results showed significant differences in terms of numbers of fish taken between the two breeding seasons at Puñihuil. In 1997/1998 penguins consumed almost exclusively anchovy, while they fed primarily on silversides in the successive year. Almost all prey, except stomatopods, were characterised as being pelagic species that occur in relatively inshore water, consistent with the foraging behaviour of Humboldt penguins. The dependence of Humboldt penguins on commercially exploited, schooling prey species makes the species particularly susceptible to changes in prey stocks, due to non-sustainable fisheries management.Communicated by O. Kinne, Oldendorf/Luhe 相似文献
939.
Superoxide production by marine microalgae 总被引:5,自引:0,他引:5
Judith-Anne?MarshallEmail author Miguel?de?Salas Tatsuya?Oda Gustaaf?Hallegraeff 《Marine Biology》2005,147(2):533-540
A survey was conducted for production of the reactive oxygen species superoxide by 37 species (65 strains) of microalgae including dinoflagellates, raphidophytes, chlorophytes, prasinophytes, eustigmatophytes and prymnesiophytes. Ichthyotoxic raphidophyte species of Chattonella were found to produce the highest environmental levels of superoxide (177×104 total chemiluminescence units). However, ichthyotoxic dinoflagellates (Karenia, Alexandrium) and the prymnesiophyte Prymnesium were also found to produce significant levels of superoxide (4×104, 3×104 and 5×104 chemiluminescence units, respectively), equivalent to that of other raphidophyte species of Heterosigma and Fibrocapsa (6×104 and 2×104, respectively). A direct relationship between cell size and superoxide production was observed (r2=0.94), with larger cells producing more superoxide per cell. Chattonella produced the most superoxide per cell (expressed as cellular chemiluminescence units), followed by the dinoflagellate species Karenia, Alexandrium, Takayama and Gymnodinium. Small cells, such as the raphidophyte Heterosigma and the prymnesiophyte Prymnesium produced very little superoxide per cell (cellular chemiluminescence units), but potentially could still produce high total levels of superoxide if present at high biomass levels. Species commonly used as aquaculture bivalve feeds such as Dunaliella, Tetraselmis, Nannochloropsis and Pavlova produced negligible levels of superoxide, even at high biomass. We speculate that superoxide, while not the sole ichthyotoxic principle, may play a wider role in algal toxicity than previously considered, and propose a broad classification of microalgae based upon superoxide production.Communicated by M.S. Johnson, Crawley 相似文献
940.
The toxicity of pesticides has been evaluated by several methods including tests with earthworms in both artificial and natural soils treated with the compounds. The ecological niches of earthworms make them good bioindicators of soil contamination. The bioaccumulation of 14C-simazine (6-chloro-N2-N4-diethyl- 1,3,5-triazine-2,4-diamine) was evaluated in earthworms (Eisenia foetida) maintained during three months in two substrates with different physical-chemical characteristics. The substrates were treated with 3.0 mg and 330 kBq of 14C-simazine kg(-1) substrate. Results indicated that worms did not influence simazine dissipation in both substrates as indicated by similar recoveries and with no statistical differences with and without earthworms. The radiocarbon recoveries were 86.8 and 95.3%, respectively in the substrates with lower and higher organic matter contents with earthworms, and 91.0 and 107.4% in the same substrates without worms. However, in earthworms the recoveries were statistically higher when they were maintained in the substrate with lower amount of organic matter (0.89%) than from the higher one (0.33%). Consequently, 14C-simazine bioconcentration factor (BCF) was also greater in the substrate with lower organic matter (6.89+/-1.55) than in the substrate with higher organic matter content (0.88+/-0.06). The results suggest that the higher soil organic matter content will cause lower probability of contamination of soil organisms with simazine. 相似文献