全文获取类型
收费全文 | 8122篇 |
免费 | 92篇 |
国内免费 | 244篇 |
专业分类
安全科学 | 159篇 |
废物处理 | 395篇 |
环保管理 | 934篇 |
综合类 | 1363篇 |
基础理论 | 1987篇 |
污染及防治 | 2012篇 |
评价与监测 | 607篇 |
社会与环境 | 953篇 |
灾害及防治 | 48篇 |
出版年
2023年 | 62篇 |
2022年 | 130篇 |
2021年 | 104篇 |
2020年 | 67篇 |
2019年 | 99篇 |
2018年 | 146篇 |
2017年 | 156篇 |
2016年 | 213篇 |
2015年 | 160篇 |
2014年 | 261篇 |
2013年 | 698篇 |
2012年 | 283篇 |
2011年 | 378篇 |
2010年 | 315篇 |
2009年 | 346篇 |
2008年 | 395篇 |
2007年 | 401篇 |
2006年 | 312篇 |
2005年 | 292篇 |
2004年 | 288篇 |
2003年 | 280篇 |
2002年 | 268篇 |
2001年 | 340篇 |
2000年 | 218篇 |
1999年 | 118篇 |
1998年 | 86篇 |
1997年 | 87篇 |
1996年 | 107篇 |
1995年 | 126篇 |
1994年 | 97篇 |
1993年 | 85篇 |
1992年 | 90篇 |
1991年 | 92篇 |
1990年 | 80篇 |
1989年 | 72篇 |
1988年 | 70篇 |
1987年 | 75篇 |
1986年 | 53篇 |
1985年 | 63篇 |
1984年 | 63篇 |
1983年 | 60篇 |
1982年 | 58篇 |
1981年 | 64篇 |
1980年 | 47篇 |
1979年 | 47篇 |
1978年 | 35篇 |
1977年 | 38篇 |
1976年 | 36篇 |
1973年 | 43篇 |
1972年 | 51篇 |
排序方式: 共有8458条查询结果,搜索用时 15 毫秒
11.
12.
Daytime sampling of mangrove and seagrass (Halophila/Halodule community) habitats every 7 wk at Alligator Creek, Queensland, Australia, over a period of 13 mo (February 1985–February
1986) using two types of seine net, revealed distinct mangrove and seagrass fish and crustacean faunas. Total abundance of
fish and relative abundance of small and large fish also varied between habitats and seasonally. Post-larval, juvenile and
small adult fish captured with a small seine-net (3 mm mesh) were significantly more abundant (4 to 10 times) in the mangrove
habitat throughout the 13 mo of sampling. Mangrove fish abundance showed significant seasonality, greatest catches being recorded
in the warm, wet-season months of the year. Relative abundances of larger fish (captured in a seine net with 18 mm mesh) in
the two habitats varied throughout the year, but did not show a seasonal pattern. At the same site, small crustaceans were
significantly more abundant in the mangroves in all but one dryseason sample. Similar comparisons for three riverine sites,
sampled less frequently, in the dry and wet seasons of 1985 and 1986, respectively, showed that in general mangrove habitats
had significantly more fish per sample, although the relative abundance of fish in mangroves and other habitats changed with
season. Crustacean catches showed a similar pattern, except that densities among sites changed with season. Fish and crustacean
abundance in mangroves varied among sites, indicating that estuaries differ in their nursery-ground value. The juveniles of
two commercially important penaeid prawn species (Penaeus merguiensis and Metapenaeus ensis) were amongst the top three species of crustaceans captured in the study, and both were significantly more abundant in the
mangrove habitat. By contrast, mangroves could not be considered an important nursery for juveniles of commercially important
fish species in northern Australia. However, based on comparisons of fish catches in other regions, the results of the present
study indicate the importance of mangroves as nursery sites for commercially exploited fish stocks elsewhere in South-East
Asia.
Contribution No. 378 from the Australian Institute of Marine Science 相似文献
13.
Data on the existence of a specific system regulating the growth, size, and structure of enterobacterial populations are first summarized in terms of the chemical ecology concept formulated by S.S. Shvarts. The role of this system in transgene functioning is described using the example of the lux operon integrated into Escherichia coli. A relatively simple test for estimating such interactions is proposed.Translated from Ekologiya, No. 2, 2005, pp. 91–96.Original Russian Text Copyright © 2005 by Pshenichnov, Maslennikova, Nikitina. 相似文献
14.
Fritz Nüßlein Ernst Anton Feicht Sigurd Schulte-Hostede Antonius Kettrup 《Environmental Sciences Europe》1997,9(3):136-142
A site contaminated by mercury serves as an example for evaluating the environmental medicine aspects of mercury emissions on individuals living in the surroundings. Based on defined, conventional scenarios, estimations of internal exposure were made for seven different age groups and with regard to such contact media as soil, air and food. Using human monitoring methods, an attempt was made to compare the epidemiological results. The site-specific and pathway-specific estimation of exposure is based on a multitude of various samples as well as on measurements of concentrations in the compartments relevant for intake. As based upon rigid guideline values, both these calculations and the epidemiological investigations reveal a slight increase in the mercury exposure. 相似文献
15.
16.
17.
In the diurnal lepidopteran fauna of the northern taiga subzone in the western Russian Plain, the species inhabiting primary biotopic complexes typical of this subzone currently account for slightly more than 60% of the total species richness and abundance. A large part of the fauna is represented by the species of more southern origin, whose expansion to the northern taiga was caused by anthropogenic transformation of landscapes between the 12th and 20th centuries and recent climate warming. 相似文献
18.
Although many conventional physical remediation methods are viewed as proven, they often only relocate wastes to other sites or into the air. How do the emerging biological and chemical in situ methods perform in the same applications? This article reviews their results (much of it in the laboratory) as well as their promise of more complete neutralization of hazardous wastes, lower capital costs, and longer-duration cleanup processes. The optimal method may be a combination of chemical and biological in situ techniques with physical pump-and-treat methods. 相似文献
19.
Dr. J. F. Bruch P. Metezeau N. Garcia-Fonknechten Y. Richard V. Tricottet B.-L. Hsi A. Kitzis C. Julien E. Papiernik 《黑龙江环境通报》1991,11(10):787-798
Three monoclonal antibodies (MAbs) against trophoblast (GB17, GB21, and GB25) and flow cytometry were used to sort trophoblast-like cells (TLCs) from peripheral blood of pregnant women. Sorted TLCs were processed for electron microscopy and fetal DNA amplification of the Y-specific sequences from mothers carrying male fetuses. At the ultra-structural level, most of the nucleated cells had the morphology of leucocytes, suggesting maternal contaminants, and we did not find the characteristic features of the free inter-villous trophoblast cells. Nevertheless, polymerase chain reaction (PCR) analysis showed an amplification of Y-specific sequences in two out of three samples of sorted TLCs. These results suggest that besides the maternal leucocytes, sufficient trophoblast nucleated fetal cells can be obtained using cell enrichment by sorting. This sensitive method holds promise for non-invasive prenatal diagnosis of fetal sex and if sufficient Y(positive) nuclei are found, for the diagnosis of selected numerical chromosome abnormalities. 相似文献
20.
N. L. Ivanova 《Russian Journal of Ecology》2002,33(2):125-129
Environmental conditions in cooling ponds of thermal power plants are favorable for marsh frogs. Their populations inhabiting Verkhne-Tagil and Reftinskoe reservoirs differ in some traits, such as size and age composition, growth rate after metamorphosis, spawning type, fecundity, and characteristics of larval development. Differentiation in body size manifests itself at the early stages of terrestrial life and progresses at later stages. As a consequence, larger individuals may reach maturity and participate in reproduction at an earlier age. 相似文献