全文获取类型
收费全文 | 749篇 |
免费 | 2篇 |
国内免费 | 18篇 |
专业分类
安全科学 | 10篇 |
废物处理 | 11篇 |
环保管理 | 38篇 |
综合类 | 290篇 |
基础理论 | 184篇 |
污染及防治 | 179篇 |
评价与监测 | 24篇 |
社会与环境 | 31篇 |
灾害及防治 | 2篇 |
出版年
2021年 | 5篇 |
2018年 | 10篇 |
2017年 | 8篇 |
2016年 | 12篇 |
2015年 | 16篇 |
2014年 | 18篇 |
2013年 | 31篇 |
2012年 | 23篇 |
2011年 | 25篇 |
2010年 | 29篇 |
2009年 | 27篇 |
2008年 | 28篇 |
2007年 | 33篇 |
2006年 | 40篇 |
2005年 | 28篇 |
2004年 | 15篇 |
2003年 | 24篇 |
2002年 | 20篇 |
2001年 | 11篇 |
2000年 | 7篇 |
1999年 | 20篇 |
1998年 | 17篇 |
1997年 | 10篇 |
1996年 | 19篇 |
1995年 | 10篇 |
1994年 | 12篇 |
1993年 | 11篇 |
1991年 | 4篇 |
1989年 | 5篇 |
1985年 | 4篇 |
1983年 | 7篇 |
1979年 | 4篇 |
1969年 | 5篇 |
1966年 | 10篇 |
1965年 | 9篇 |
1964年 | 10篇 |
1963年 | 14篇 |
1962年 | 6篇 |
1961年 | 7篇 |
1960年 | 7篇 |
1959年 | 8篇 |
1958年 | 8篇 |
1957年 | 9篇 |
1956年 | 13篇 |
1955年 | 12篇 |
1954年 | 7篇 |
1953年 | 10篇 |
1950年 | 4篇 |
1939年 | 5篇 |
1934年 | 5篇 |
排序方式: 共有769条查询结果,搜索用时 0 毫秒
81.
Benjamin M. Jones Christopher D. Arp Kenneth M. Hinkel Richard A. Beck Joel A. Schmutz Barry Winston 《Environmental management》2009,43(6):1071-1084
Lakes are dominant landforms in the National Petroleum Reserve Alaska (NPRA) as well as important social and ecological resources.
Of recent importance is the management of these freshwater ecosystems because lakes deeper than maximum ice thickness provide
an important and often sole source of liquid water for aquatic biota, villages, and industry during winter. To better understand
seasonal and annual hydrodynamics in the context of lake morphometry, we analyzed lakes in two adjacent areas where winter
water use is expected to increase in the near future because of industrial expansion. Landsat Thematic Mapper and Enhanced
Thematic Mapper Plus imagery acquired between 1985 and 2007 were analyzed and compared with climate data to understand interannual
variability. Measured changes in lake area extent varied by 0.6% and were significantly correlated to total precipitation
in the preceding 12 months (p < 0.05). Using this relation, the modeled lake area extent from 1985 to 2007 showed no long-term trends. In addition, high-resolution
aerial photography, bathymetric surveys, water-level monitoring, and lake-ice thickness measurements and growth models were
used to better understand seasonal hydrodynamics, surface area-to-volume relations, winter water availability, and more permanent
changes related to geomorphic change. Together, these results describe how lakes vary seasonally and annually in two critical
areas of the NPRA and provide simple models to help better predict variation in lake-water supply. Our findings suggest that
both overestimation and underestimation of actual available winter water volume may occur regularly, and this understanding
may help better inform management strategies as future resource use expands in the NPRA. 相似文献
82.
The concept of substituting bio‐diesel produced from plantations on eroded soils for conventional diesel fuel has gained wide‐spread attention in India. In recent months, the Indian central Government as well as some state governments have expressed their support for bringing marginal lands, which cannot be used for food production, under cultivation for this purpose. Jatropha curcas is a well established plant in India. It produces oil‐rich seeds, is known to thrive on eroded lands, and to require only limited amounts of water, nutrients and capital inputs. This plant offers the option both to cultivate wastelands and to produce vegetable oil suitable for conversion to bio‐diesel. More versatile than hydrogen and new propulsion systems such as fuel cell technology, bio‐diesel can be used in today's vehicle fleets worldwide and may also offer a viable path to sustainable transportation, i.e., lower greenhouse gas emissions and enhanced mobility, even in remote areas. Mitigation of global warming and the creation of new regional employment opportunities can be important cornerstones of any forward looking transportation system for emerging economies. 相似文献
83.
84.
Tarsal substrate adhesion in insects is based on the effect of a thin film of liquid in the contact zone, which is deposited
as droplets on the surface an insect has walked on, but as yet, little is known about the chemical composition of the liquid.
In the present study, interference reflection microscopical images of the tarsal contact and footprints of Gastrophysa viridula (Coleoptera: Chrysomelidae) are depicted and the chemical composition of tarsal liquids and cuticular components are investigated
by means of solid-phase microextraction and solvent extraction of whole beetles and footprints. Based on this comparative
methodical approach, we are first to provide evidence from direct sampling for the chemical congruence of cuticular lipids
and tarsal liquid in beetles. Furthermore, differences resulting from the applied sampling techniques are assessed and advantages
of the respective methods are discussed. 相似文献
85.
A method was developed for the risk assessment of a military waste site. The method consists of two steps: 1. evaluation of the exposure through different pathways and 2. derivation of substance-specific tolerable intake levels. In this first part of the paper the quantitative exposure analysis will be discussed. Exposure depends on the conditions at the contaminated site (e.g. soil characteristics), the type of utilisation (residential area, industrial area etc.) and the substance properties. In a specific utilisation scenario, e.g. as residential area, different exposure pathways are contributing to the total contaminant uptake. Because of the properties of nitroaromatic compounds like 2,4,6-trinitrotoluene (good resorption through skin and accumulation in plants) exposure via dermal soil contact and via consumption of plants gains special importance. With these two exposure pathways as examples we explain the quantification of the exposure through different pathways by so-called exposure factors. By comparing the total exposure with tolerable intake levels for the compounds, waste site specific soil pollutant levels can be established (see second part of the paper in UWSF 6/94). 相似文献
86.
2,2′-Dichlorodivinylarsine chloride (Lewisite II) react by room temperature quickly with alcohols in an equilibrium reaction to yield 2,2′-Dichlorodivinylarsine ether. The reactions are not quantitative. The methyl-, ethyl-and propylether are not stable. 相似文献
87.
88.
89.
In the presented paper, the pHstat-procedure is compared with four simple extraction procedures. These procedures make use of the following extraction solutions: distilled water (based on DIN 38414 part 4, DIN-S4), 1 mol/L ammonium nitrate, 1 mol/L ammonium acetate at pH 7.0 and 1 mol/L sodium acetate at pH 5.0, respectively. The extraction procedures were applied to 10 different soil samples and 2 sludges. The DIN-S4-procedure shows the lowest amounts of mobilized copper. The highest parts are extracted by sodium acetate solution. For the procedures investigated, the mobilized amounts extracted by ammonium acetate solution are most comparable with those of the pHstat-procedure. The simple sodium acetate procedure is useful for screening to select significant samples from a large number of soils. Thus, the high effort caused by the pHstat-procedure can be reduced to a minimum through the application of this screening procedure. The application of this screening, however, is difficult for samples containing large parts of organic compounds, e.g. sewage sludge. These samples show a different extracting behaviour. 相似文献
90.
Jürgen Breitung Dirk Bruns-Nagel Eberhard von Löw Klaus Steinbach Lothar Kaminski Rainer Haas Diethard Gemsa 《Environmental Sciences Europe》1995,7(4):195-200
Within the limits of a feasability study abouton-site bioremediation methods for TNT-contaminated soils, composting was chosen as a very promising and cheap method. This method was critically compared with those described in the literature and was primarily rated under ecotoxicological aspects. The investigated location is the former munition plant «Tanne» in the aerea of Clausthal-Zellerfeld in Lower Saxony, Germany. To estimate the autochtonic microflora, we assessed the number of aerobic heterotrophic bacteria and determined their respiration activity in soils. In addition, we isolated bacteria and examined their capacity to metabolize TNTin vitro. Both the amount of autochtonic microrganisms (4.7×108 to 1.2×1010 colony forming units (cfu)/kg dryweight) as well as their respiration activity did not correlate with the concentrations of nitrotoluenes in the soils. With high contaminated soil (20 g TNT/kg dry weight) we carried out a small compost in the range of 10 liters. During 28 days of composting TNT-concentration decrease over 90% and only minor amounts of monoaminodinitrotoluenes were generated. However, an acidic pretreatment of the compost material at the end of the reaction showed that TNT could be partially resolved under these extreme conditions and that an ecotoxicological risk may still exist. Possible changes in the realization of the composting process in order to make sure that the contaminants are savely bound to the humin matrix are discussed. 相似文献