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121.
Daily particle samples were collected in Chillán, Chile, at six urban locations from September 1, 2001, through September 30, 2003. Aerosol samples were collected using monitors equipped with a Sierra Andersen 246-b cyclone inlet on Teflon filters. Average concentrations of coarse particulate matter (PM10) for the 2001-2003 period ranged from 43.4 microg/m3 to 81.8 microg/m3 across the six sites. Annual PM10 concentration levels exceeded the European Union concentration limits. Mean PM10 levels during the cold season (April through September) were more than twice as high as those observed in the warm season (October through March). Average contributions to PM10 from organic matter, soil dust, nitrate (NO3-), elemental carbon, ammonium (NH4+), and sulfate (SO4(2-)) were 31%, 27%, 11%, 8%, 7%, and 5%, respectively. The chemical analyses indicated that carbonaceous substances were the most abundant components of PM10 in cold months, whereas crustal material was the most abundant component of PM10 during warm months. Higher concentration levels were observed in the downtown area suggesting a clear anthropogenic origin, whereas in the rural sites the source was mainly natural, such as resuspended soil dust associated with traffic on unpaved roads and agricultural activities.  相似文献   
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A Wolf  K Bunzl  F Dietl  W.F Schmidt 《Chemosphere》1977,6(5):207-213
Distribution coefficients for the sorption of Pb2+, Cu2+, Cd2+ and Zn2+ by peat were determined as a function of the Ca2+-content of peat as well as of the Ca2+-concentration in the solution. The amount of heavy metal ions taken up was measured for Cu2+, Cd2+ and Zn2+ by atomic absorption spectrometry and for Pb2+ by using Pb-212 as a radioactive tracer.The results show that the distribution coefficients of the heavy metal ions increase, if one increases the initial ratio of the Ca2+H+-ions in the peat phase. The distribution coefficients for the heavy metal ions decrease, however, if - at constant initial Ca2+-content of the peat - the Ca2+-concentration of the solution is increased.  相似文献   
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125.
Paper recycling is an environmental important activity that is carried out in all the countries, but during the recycling process a paper waste is produced. Generally these wastes are placed in landfill sites but it is possible to profit it as secondary fuel and raw material in manufacture furnaces.

In this work the combustion of the waste papers with cement and ceramic raw material has been studied with the objective to analyse the interaction of these substances with the emitted pollutants like PAHs and PCDD/Fs.

The results of the study show that the presence of inorganic material produces an increment in the lighter PAH emission but chlorinated compounds are not affected. The PCDD/F emission level found in the combustion of this waste is quite low compared with other wastes subjected to similar conditions.  相似文献   

126.
A possible additional means for aiding in the identification of soft corals based on their sesquiterpene composition, as determined by gas-liquid chromatography (GLC), is discussed. The use of this method for several species of Sinularia and Sarcophyton is illustrated. Several sesquiterpenes were identified, some of them for the first time from marine origin. Preliminary tests indicate that the sesquiterpene composition in the tested soft corals remained quite constant during different seasons of the year. It is suggested that such finger prints are produced by the corals themselves and not by the zooxanthellae, and that they are species-specific.  相似文献   
127.
A study was conducted to determine the annual average radon concentrations in California residences, to determine the approximate fraction of the California population regularly exposed to radon concentrations of 4 pCi/l or greater, and to the extent possible, to identify regions of differing risk for high radon concentrations within the state. Annual average indoor radon concentrations were measured with passive (alpha track) samplers sent by mail and deployed by home occupants, who also completed questionnaires on building and occupant characteristics. For the 310 residences surveyed, concentrations ranged from 0.10 to 16 pCi/l, with a geometric mean of whole-house (bedroom and living room) average concentrations of 0.85 pCi/l and a geometric standard deviation of 1.91. A total of 88,000 California residences (0.8 percent) were estimated to have radon concentrations exceeding 4 pCi/l. When the state was divided into six zones based on geology, significant differences in geometric mean radon concentrations were found between several of the zones. Zones with high geometric means were the Sierra Nevada mountains, the valleys east of the Sierra Nevada, the central valley (especially the southern portion), and Ventura and Santa Barbara Counties. Zones with low geometric means included most coastal counties and the portion of the state from Los Angeles and San Bernardino Counties south.  相似文献   
128.
Tillage has been and will always be integral to crop production. Tillage can result in the degradation of soil, water, and air quality. Of all farm management practices, tillage may have the greatest impact on the environment. A wide variety of tillage equipment, practices and systems are available to farmers, providing opportunities to enhance environmental performance. These opportunities have made tillage a popular focus of environmental policies and programs such as environmental indicators for agriculture. This paper provides a very brief examination of the role of tillage in crop production, its effect on biophysical processes and, therefore, its impact on the environment. Models of biophysical processes are briefly examined to demonstrate the importance of tillage relative to other farm management practices and to demonstrate the detail of tillage data that these models can demand. The focus of this paper is an examination of the use of information on tillage in Canada's agri-environmental indicators initiative, National Agri-environmental Health Analysis and Reporting Program (NAHARP). Information on tillage is required for several of the indicators in NAHARP. The type of data used, its source, and its quality are discussed. Recommendations regarding the collection of tillage data and use of tillage information are presented.  相似文献   
129.
The Convention on Biological Diversity (CBD) originating from 1992 today has 190 Parties. In 2000 the convention decided on a programme of work on agricultural biodiversity which explicitly included the diversity of races and types of species used in agriculture. This programme was scheduled for an In-Depth Review at the Ninth Conference of the Parties (COP 9). The preparatory meetings of the Subsidiary Body on Scientific, Technical and Technological Advice (SBSTTA) already indicated that the production and use of biofuels would be a controversial issue during COP. Parties producing biofuels emphasised the CO2 neutrality while importing countries called for standards for sustainable production. Developing countries mentioned the risk of losing agricultural area suitable for food production and indigenous representatives asked for social standards in agricultural production and respecting of their land ownership. A compromise could only be found at ministerial level during the last conference day, agreeing that all production of biofuels should be sustainable in relation to biodiversity and under this condition urging Parties to promote the production and use of biofuels. Research on the positive and negative impacts of biofuels should be conducted.  相似文献   
130.
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