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651.
罗国兵 《中国环境管理干部学院学报》2013,(3):9-12,51
在水质检测工作中,质量控制方法是确保检测数据准确的一种重要手段。当前水质检测实验室中常用的质控手段有盲样考核、平行测定、加标回收、比对试验、期间核查、相关性分析与质量监督六类,通过分析比较这些质控手段在分析检测中的差异及其对检测结果的影响,为提升水质检测工作质量,出具科学、公正的检测报告提供保障。 相似文献
652.
Burger J Gochfeld M Powers CW Kosson DS Halverson J Siekaniec G Morkill A Patrick R Duffy LK Barnes D 《Journal of environmental management》2007,85(1):232-244
It is increasingly clear that a wide range of stakeholders should be included in the problem formulation phase of research aimed at solving environmental problems; indeed the inclusion of stakeholders at this stage has been formalized as an integral part of ecological risk assessment. In this paper, we advocate the additional inclusion of stakeholders in the refinement of research methods and protocols and in the execution of the research, rather than just at the final communication and reporting phase. We use a large study of potential radionuclide levels in marine biota around Amchitka Island as a case study. Amchitka Island, in the Aleutian Island Chain of Alaska, was the site of three underground nuclear tests (1965-1971). The overall objective of the biological component of the study was to collect a range of marine biota for radionuclide analysis that could provide data for assessing current food safety and provide a baseline for developing a plan to monitor human and ecosystem health in perpetuity. Stakeholders, including regulators (State of Alaska), resource trustees (US Fish and Wildlife Service, State of Alaska), representatives of the Aleut and Pribilof Island communities, the Department of Energy (DOE), and others, were essential for plan development. While these stakeholders were included in the initial problem formulation and approved science plan, we also included them in the refinement of protocols, selection of bioindicators, selection of a reference site, choice of methods of collection, and in the execution of the study itself. Meetings with stakeholders resulted in adding (or deleting) bioindicator species and tissues, prioritizing target species, refining sampling methods, and recruiting collection personnel. Some species were added because they were important subsistence foods for the Aleuts, and others were added because they were ecological equivalents to replace species deleted because of low population numbers. Two major refinements that changed the research thrust were (1) the inclusion of Aleut hunters and fishers on the biological expedition itself to ensure that subsistence foods and methods were represented, and (2) the addition of a fisheries biologist on a NOAA research trawler to allow sampling of commercial fishes. Although the original research design called for the collection of biota by Aleut subsistence fishermen, and by a commercial fishing boat, the research was modified with continued stakeholder input to actually include Aleuts and a fisheries biologist on the expeditions to ensure their representation. The inclusion of stakeholders during the development of protocols and the research itself improved the overall quality of the investigation, while making it more relevant to the interested and affected parties. Final responsibility for the design and execution of the research and radionuclide analysis rested with the researchers, but the process of stakeholder inclusion made the research more valuable as a source of credible information and for public policy decisions. 相似文献
653.
Dominique Berteaux Joël Bêty Eddie Rengifo Jean-Marie Bergeron 《Behavioral ecology and sociobiology》1999,45(3-4):283-291
Multiple paternity in single litters conceived in the wild was recently demonstrated in meadow voles (Microtuspennsylvanicus). In this study, we used an experimental approach (males tethered and females allowed to mate freely with one or several
males) to investigate the role of female meadow voles in multiple paternity. We found that among 29 (of 39) females that copulated
during our experiment, 79.3% chose to mate with more than one male. Female behavior in meadow voles thus clearly promotes
multiple paternity and their role is an active one. Some of the hypotheses explaining promiscuity in meadow voles should be
reconsidered in light of this result. We do not know the primary determinant of female mate choice, but male body mass played
a secondary role in driving female preferences. The partial dependence between male body mass and female choice, coupled with
the active role played by females, indicates that intersexual selection has the potential for reinforcing the effects of intrasexual
selection (male-male dominance relationships) in this species. Finally, we demonstrate that the time period over which tests
are conducted is an important part of the design of experiments aimed at understanding the role of females in multiple paternity.
Received: 14 April 1998 / Accepted after revision: 12 September 1998 相似文献
654.
铜铝复合式CPU风冷散热器的实验研究 总被引:1,自引:0,他引:1
随着计算机的迅猛发展,CPU芯片的集成度、封装密度以及工作频率的不断提高,其发热量也不断增大,从而对CPU散热器的散热性能的要求也提高了.通过分析散热器的散热性能及性能评价方法,对放射状铜铝复合式CPU散热器进行了测试,建立不同风速下功率与CPU表面平衡温度关系曲线和不同风速下功率与热阻关系曲线,为改进散热器提供了实验数据.图3,参5. 相似文献
655.
Impact of Criticism of Null-Hypothesis Significance Testing on Statistical Reporting Practices in Conservation Biology 总被引:2,自引:0,他引:2
FIONA FIDLER§ MARK A. BURGMAN GEOFF CUMMING† ROBERT BUTTROSE NEIL THOMASON‡ 《Conservation biology》2006,20(5):1539-1544
Abstract: Over the last decade, criticisms of null-hypothesis significance testing have grown dramatically, and several alternative practices, such as confidence intervals, information theoretic, and Bayesian methods, have been advocated. Have these calls for change had an impact on the statistical reporting practices in conservation biology? In 2000 and 2001, 92% of sampled articles in Conservation Biology and Biological Conservation reported results of null-hypothesis tests. In 2005 this figure dropped to 78%. There were corresponding increases in the use of confidence intervals, information theoretic, and Bayesian techniques. Of those articles reporting null-hypothesis testing—which still easily constitute the majority—very few report statistical power (8%) and many misinterpret statistical nonsignificance as evidence for no effect (63%). Overall, results of our survey show some improvements in statistical practice, but further efforts are clearly required to move the discipline toward improved practices. 相似文献
656.
657.
Dr A. L. Zaslav D. Blumenthal J. E. Fox K. A. Thomson R. Segraves M. E. Weinstein 《黑龙江环境通报》1993,13(7):569-573
Extra genetic material that is euchromatic is generally regarded to be associated with phenotypic abnormalities. However, recent studies suggest that this is not always the case. Chromosome analysis was performed on amniotic fluid cells from a 37-year-old phenotypi-cally normal patient referred for advanced maternal age. All the cells analysed showed a karyotype of 46, XY, 1p-K The 1p+ chromosome had extra genetic material of uncertain origin in chromosome band region 1p21 →31. Chromosome analysis on the father revealed a normal 46, XY male karyotype. The mother's karyotype showed the same 1p+ chromosome. C and Q banding, as well as silver staining studies, in both the mother and the fetus support the interpretation that the extra chromosomal material was euchromatic in nature. This 1p + chromosome may be characterized as a euchromatic heteromorphism. Euchromatic hetero-morphisms not associated with phenotypic abnormalities have been reported for chromosomes 9 and 16. To the best of our knowledge, this is the first report involving this type of cytogenetic anomaly on chromosome number 1 in a phenotypically normal mother and infant. 相似文献
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