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441.
Lingyun Wang Gangdou Ding Zhiguang Zhou Xun Liu Yixiao Wang Heidi Qunhui Xie Tuan Xu Pu Wang Bin Zhao 《环境科学学报(英文版)》2017,29(1):165-172
The health risk of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and dioxin-like PCBs (dl-PCBs) to human being should be assessed regularly. To evaluate the contamination levels in various food products in the Chinese market and to assess the dietary exposure of the Chinese population, 11 varieties of food groups totaling 634 samples including beef and mutton, chicken and duck, pork, fish and seafood, milk and dairy products were evaluated. The average concentrations of PCDD/Fs in all groups ranged from 0.291 to 8.468 pg/g whole weight (w.w.). The average toxic equivalency concentrations were from 0.012 pg TEQ/g w.w. for cereal to 0.367 pg TEQ/g fat for marine oil. OCDD and 2,3,7,8-TCDF were the dominant congeners in foodstuffs. The dietary estimated mean intake for the Chinese rural and urban populations were 0.656 and 0.514 pg TEQ/kg body weight/day, respectively, however, the cereal group exposure were higher to the estimate daily intake and contributed 81% for rural and 48% for urban population, followed by fish and seafood which contributed 4% and 16% to the estimate daily intake. The estimated dietary intakes were compared with the toxicological reference values and showed that both rural and urban populations were well below those values. 相似文献
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443.
针对三峡库区工业源污染排放量大,对库区水生态环境安全危害大的特点,以库区湖北段工业源为研究对象,采用实际监测和企业申报监测数据方式,辅以排污系数计算方法,统计分析了1995-2007年工业废水量和主要污染物COD的排放量,并采用灰色-马尔柯夫链模型预测2008-2020年的污染负荷.结果表明,自2005年以后,工业废水的排放量呈现逐渐下降的趋势,在2007年达到1 857.13万t,2008年以后逐渐增加.COD的排放量总体呈逐渐下降的趋势,只是在2001年出现上升,到2007年底COD的排放量为611.21 t.随着工业源污染物全防全控的加强,预计工业污染负荷会逐步减少. 相似文献
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445.
Luděk Bartoš Jitka Bartošová Jan Pluháček Jana Šindelářová 《Behavioral ecology and sociobiology》2011,65(8):1567-1572
Based on questionnaires from horse breeders, we found that bringing a pregnant mare which had been mated away from home into
a vicinity of a familiar male who was not the father of her foetus increased probability of pregnancy disruption. These mares
aborted in 31% of cases, while none of those mated within the home stable aborted. Repeated sexual activity either by a stallion
or dominant gelding from the normal home group was observed shortly after the mare came from away-mating. Pregnant mares isolated
from home males by a fence were even seen soliciting them over the fence. We speculate that, once returned to the home “herd”,
and introduced to familiar males, mares were more likely to terminate their pregnancy to save energy and avoid likely future
infanticidal loss of their progeny by dominant male(s) of the home social group. This is a newly discovered phenomenon where
a mare manipulates the male’s paternity assessment by promiscuous mating. It may explain a common increased incidence of foetal
loss in domestic horses occurring in nearly 40% of pregnancies. We conclude that the common practice of transporting the mare
for mating and then bringing her back to an environment with males, stallions or geldings, which did not sire the foetus,
is the main cause of high percentages of pregnancy disruption in domestic horses. 相似文献
446.
Jonathan N. Pruitt Nicholas DiRienzo Simona Kralj-Fišer J. Chadwick Johnson Andrew Sih 《Behavioral ecology and sociobiology》2011,65(10):1987-1995
Research on consistent individual differences in behavior, or “behavioral syndromes”, continues to grow rapidly, and yet,
the aspects of behavior under consideration have remained remarkably limited. Here, we consider individual variation in consistency
of choice (termed here “choosiness”), as expressed during habitat choice. We repeatedly tested the responses of female Western
Black Widows, Latrodectus hesperus, to two cues of habitat quality: prey chemical cues and variation in web site illuminance. We estimated females’ response
by the distance they positioned themselves from (1) the source of prey chemical cues and (2) the darkest edge of our test
arena. Individuals with low variance in their responses are deemed more “choosy”, whereas individuals with high variance are
deemed less “choosy”. Generally, most females initiated web construction near the source of the prey chemical cues and tended
to place themselves in low-light conditions. However, we detected strong, repeatable differences in females’ intensity of
response, and within-individual variance of response (i.e., choosiness) was correlated across situations: females with highly
consistent responses towards cricket chemical cues also exhibited highly consistent responses towards variation in light conditions.
When deprived of food for extended periods, females were indistinguishable in their responses towards prey chemical cues,
but tended to initiate web construction in brighter lighting conditions. Food-deprived females universally exhibited higher
variance and diminished consistency in their responses (i.e., they were less choosy). Additionally, higher choosiness was
associated with greater mass loss during choice trials, suggesting choosiness is energetically costly. Our results demonstrate
that consistency of response to environmental cues is yet another element of behavior that varies among individuals and variation
in choosiness could beget speed/quality trade-offs during animal decision making. 相似文献
447.
?i?dem Co?kun Hepcan Mehmet B��lent ?zkan 《Environmental monitoring and assessment》2011,174(1-4):157-170
The study involves the Çe?me?CUrla Peninsula, where habitat fragmentation and loss, which threaten biological diversity, have become an urgent matter of concern in recent decades. The study area has been subjected to anthropogenic pressures and alterations due to ongoing and impending land uses. Therefore, ecological networks, as an appropriate way to deal with habitat fragmentation and loss and to improve ecological quality, were identified in the study area as one of the early attempts in the country to maintain its rich biodiversity. In this sense, core areas and ecological linkages as primary components of ecological networks were established on the basis of sustaining natural habitats. A GIS-based model was created to identify core areas and to facilitate the ecological connectivity. The modeling process for core areas and corridors combined 14 and 21 different variables, respectively. The variables were used as environmental inputs in the model, and all analyses were materialized in ArcGIS 9.2 using grid functions of image analysis and spatial analyst modules. As a result, six core areas and 36 corridor alternatives were materialized. Furthermore, some recommendations for the implementation and management of the proposed ecological networks were revealed and discussed. 相似文献
448.
Guttová A Lackovičová A Pišút I Pišút P 《Environmental monitoring and assessment》2011,182(1-4):361-373
The study illustrates the response of epiphytic lichens to changing atmospheric conditions in Central Europe, where the emission of air pollutants has significantly decreased from 1990, in the area in and around Bratislava City. Variation in concentrations of seven metal elements (Cu, Cd, Cr, Mn, Ni, Pb and Zn) in the thalli of Evernia prunastri, Hypogymnia physodes and Parmelia sulcata is assessed. Samples of these species were exposed in lichen bags in 39 sites throughout the territory of the city (more than 300 km(2)) during the period December 2006-February 2007. The samples were analyzed by AAS for metal element contents prior to and after exposure. The decrease in air pollution (for all studied elements by more than 90%) corresponded to a decrease in the accumulation of elements in lichen thalli, e.g. the contents of Pb decreased by 69% and of Cd by 34% on average. The results show also variations in accumulation between with different lichen species. The background values of metal element contents in thalli of H. physodes growing in situ were measured in semi-natural sites in Slovakia. It is suggested that these can be used as a reference in large-scale monitoring studies in Central Europe. Analysis of compatible data from the current study, and the study performed at the end of 1990s shows a significant decrease of metal elements in the air pollution load. 相似文献
449.
Peter Gajšek Dina šimunic 《International journal of occupational safety and ergonomics》2013,19(2):187-194
The rapid growth of mobile communications has not only led to a rising number of mobile telephones. It has also made base stations essential for services widespread on many roofs. However, not everyone is aware that working close to sources of high frequency electromagnetic fields (EMF), such as transmitter antennas for mobile phones, pagers and police, fire and other emergency services, can result in high EMF exposure. This paper deals with measurements and calculations of the compliance boundary for workers in one typical roof top base station setting according to EU Directive and other relevant EN standards. 相似文献