全文获取类型
收费全文 | 13117篇 |
免费 | 90篇 |
国内免费 | 244篇 |
专业分类
安全科学 | 159篇 |
废物处理 | 663篇 |
环保管理 | 1636篇 |
综合类 | 1840篇 |
基础理论 | 3889篇 |
污染及防治 | 2578篇 |
评价与监测 | 991篇 |
社会与环境 | 1647篇 |
灾害及防治 | 48篇 |
出版年
2023年 | 58篇 |
2022年 | 130篇 |
2021年 | 104篇 |
2020年 | 67篇 |
2019年 | 99篇 |
2018年 | 676篇 |
2017年 | 659篇 |
2016年 | 645篇 |
2015年 | 206篇 |
2014年 | 262篇 |
2013年 | 696篇 |
2012年 | 482篇 |
2011年 | 1087篇 |
2010年 | 710篇 |
2009年 | 781篇 |
2008年 | 976篇 |
2007年 | 1208篇 |
2006年 | 308篇 |
2005年 | 357篇 |
2004年 | 317篇 |
2003年 | 376篇 |
2002年 | 400篇 |
2001年 | 353篇 |
2000年 | 227篇 |
1999年 | 120篇 |
1998年 | 107篇 |
1997年 | 84篇 |
1996年 | 107篇 |
1995年 | 126篇 |
1994年 | 96篇 |
1993年 | 85篇 |
1992年 | 90篇 |
1991年 | 92篇 |
1990年 | 79篇 |
1989年 | 71篇 |
1988年 | 69篇 |
1987年 | 75篇 |
1986年 | 52篇 |
1985年 | 63篇 |
1984年 | 72篇 |
1983年 | 62篇 |
1982年 | 58篇 |
1981年 | 64篇 |
1980年 | 47篇 |
1979年 | 46篇 |
1977年 | 38篇 |
1976年 | 36篇 |
1974年 | 34篇 |
1973年 | 43篇 |
1972年 | 51篇 |
排序方式: 共有10000条查询结果,搜索用时 62 毫秒
41.
Tone River supplies most of the water requirements of the Tokyo Metropolitan Area (TMA). Lowering of Tone flow and yearly
fluctuation, however, is causing water shortage along TMA nowadays. This study investigated the future water availability
scenarios under climatic changes. A state-of-the-art approach to utilize the output of several GCM has been demonstrated to
investigate the future water availability scenarios for TMA from the Tone River. An integrated modeling approach for water
balance considering several hydrological risk indices was adopted to quantify the future changes in this case. It is observed
that the future summer precipitation along the Tone basin is going to be increased considerably, while an almost constant
or decreasing trend is observed for winter season. Natural flow availability for winter or spring seasons thus can be crucial
under future scenarios. After reservoir routing, the hydrological risk indices estimated, however, were not found to be changed
significantly due to the presence of a robust reservoir system at the upstream. 相似文献
42.
E. A. Kleshcheva 《Russian Journal of Ecology》2007,38(2):94-100
A method for estimating the current state of plant communities based on the ecological amplitudes of constituent species is proposed. An original program, Fitoindikatsiya, has been developed to compute the indices of disturbance and homogeneity of plant communities from species ecological scale values. The current state of pine forests in the part of Novosibirsk oblast east of the Ob River has been analyzed; slightly, moderately, and severely disturbed zones have been distinguished. 相似文献
43.
Geochemical characteristics of surficial sediments in the Panangad region of Cochin estuary, the largest brackish-water humid ecosystem in the south-west coast of India, were analysed. Temporal variations in nutrient stoichiometry, seasonal characteristics of redox elements Fe and S, and the phosphorus geochemistry were employed for the purpose. The stoichiometric analysis pointed towards autochthonous origin of organic matter, possibility of nitrogen limitation, and allochthonous modification of redox conditions. Seasonal variations were not statistically significant for all the geochemical parameters, whereas significant spatial variations were observed with lower values at sandy stations, suggesting that the texture of the sediments is the main factor influencing the sediment geochemistry. Significant inter-relations between the geochemical parameters also suggest a common control mechanism. Based on these geochemical characteristics, the study region can be effectively categorized into two distinct zones, viz. (1) erosion and transportation and (2) deposition zones. 相似文献
44.
45.
46.
Indices of abundance and reproduction rate are considered in some groups of aquatic and terrestrial vertebrates from the zones of technogenic disasters. Upon a critical population decline caused by external destructive factors, such as emissions of acute ecotoxicants, the ecophysiological and behavioral compensatory mechanisms are activated, which provide for restoration of the total population size to the optimum within a short period of time. Environmental pollution with substances disturbing the reproductive function has the gravest consequences for animals. In this case, population size may remain fairly high, and, therefore, the effect of enhanced reproduction as a response to population decline does not take place, which eventually leads to a gradual but irreversible destruction of the population. Pathologies of reproduction should be used as a criterion for assessing the state of animals in the zones of technogenic disasters.Translated from Ekologiya, No. 1, 2005, pp. 32–38.Original Russian Text Copyright © 2005 by Shilova, Shatunovskii. 相似文献
47.
48.
New data on the composition of surface assemblages of plant macroremains from soil and swamp samples have been obtained in the study of geomorphologically different localities in the middle reaches of the Nizhnyaya Tunguska River. The results of paleocarpological analysis of forest soil sections supported by relevant palynological and geochronological data are presented. Natural changes of the forest cover over the past 2400 years and quantitative characteristics of the paleoclimate during each stage are described.Translated from Ekologiya, No. 1, 2005, pp. 3–10.Original Russian Text Copyright © 2005 by Koshkarova, Koshkarov. 相似文献
49.
50.
In the past 20 years a variety of indices have been suggested for measuring the severity of trauma, however none of them meets the requirement of being a simple and objective instrument that can be utilized efficiently by lay persons and providers of health services without previous experience in triaging. A new system has been proposed which meets this requirement and which has been validated with 197 injured persons at the emergency ward of the Valle University Hospital in Call, Colombia. The instrument showed a high level of concordance with the conventional triaging method and classifies victims into four categories: critical with recovery unlikely, critical but recoverable, moderately serious, and ambulatory. There is discussion on the reliability of this instrument and it is recommended that it be validated with victims from larger disasters. Regardless, it has the advantage of being specific and free of the subjectivity that characterizes other indices. 相似文献