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971.
环境监测中仪器分析方法不确定度的评估(Ⅰ) 总被引:1,自引:2,他引:1
结合我国环境监测的实际情况,通过对环境监测中常用仪器分析方法中测量不确定度的评估,主要对环境监测中常用仪器分析方法不确定度的来源如称量、体积校准、温度波动、标准物质、化学试剂、摩尔质量、工作曲线、方法和仪器重复性、仪器显示和读数、数字修约等作一评述,并指出了环境监测中常用仪器分析方法测量不确定度的评估应注意解决的问题。 相似文献
972.
Abstract: Water industry experts have been arguing that the traditional techniques are not an accurate means of measuring water contamination. This is mainly because these techniques emphasize neither the stochastic nature of the water contamination process nor the precision and the accuracy of the tested methods used by environmental laboratories. In this work, we describe the development and application of prototype Dynamic Bayesian Networks (DBNs) that model ground‐water quality to determine the impact of chemical contaminants on ground‐water quality in the Salalah area, which is allocated to the south of Oman. We also present a new technique for data pre‐processing because it is needed for the treatment of ground‐water datasets that are used as the data source to learn the probabilities for dynamic decision models. Among more than 20 wells in area, only four wells were selected to be analyzed and the results show that we achieved an acceptable level of efficiency. 相似文献
973.
Heath W. Whitacre Brett B. Roper Jeffrey L. Kershner 《Journal of the American Water Resources Association》2007,43(4):923-937
Abstract: Stream monitoring programs commonly measure physical attributes to assess the effect of land management on stream habitat. Variability associated with the measurement of these attributes has been linked to a number of factors, but few studies have evaluated variability due to differences in protocols. We compared six protocols, five used by the U.S. Department of Agriculture Forest Service and one by the U.S. Environmental Protection Agency, on six streams in Oregon and Idaho to determine whether differences in protocol affect values for 10 physical stream attributes. Results from Oregon and Idaho were combined for groups participating in both states, with significant differences in attribute means for 9 out of the 10 stream attributes. Significant differences occurred in 5 of 10 in Idaho, and 10 of 10 in Oregon. Coefficients of variation, signal‐to‐noise ratio, and root mean square error were used to evaluate measurement precision. There were differences among protocols for all attributes when states were analyzed separately and as a combined dataset. Measurement differences were influenced by choice of instruments, measurement method, measurement location, attribute definitions, and training approach. Comparison of data gathered by observers using different protocols will be difficult unless a core set of protocols for commonly measured stream attributes can be standardized among monitoring programs. 相似文献
974.
975.
当前,我国矿山环境问题突出。重点分析了矿山开采环境问题的特殊性,这些特殊性包括矿业对地域区位的依赖性、破坏的大量不确定性以及不可逆性。根据特殊性,讨论了环境经济学的适用性。不确定问题转化为确定性问题或者风险问题依赖于技术层面学科(如矿山环境影响评价和矿山环境地质学等)的支撑。最后指出随着这些技术学科的发展,矿山环境问题就会更精确地纳入成本——效益分析框架,从而发挥更大的作用。 相似文献
976.
977.
978.
介绍了嘉兴发电厂二期工程设计中采用的节水优化措施.经过优化后的实际淡水取水量仅为0.11 m3/s,低于《火力发电厂设计技术规程》要求的0.12 m3/s指标,且系统运行正常. 相似文献
979.
There is an increasing demand from conservation agencies for site-specific critical loads (CL); unfortunately, there is often
very little specific information on a site to determine the important parameters needed to calculate the CL or on the spatial
location of the “designated feature” in a site. Determining the most appropriate CL therefore involves using expert judegement
to make decisions with incomplete and uncertain information. Endorsement Theory (Cohen, 1985) and Dempster–Shafer statistics (Dempster, 1967; Shafer, 1976) are, respectively, a decision-theoretic and a statistical technique for reasoning under those conditions (uncertainty and
incompletness). A key reason for applying these techniques is that they make expert opinion explicit and available for scrutiny.
Both techniques have been applied to the problem of setting an appropriate site specific CL, using heathland sites as a case
study. Inital findings are encouraging; the uncertainty in expert judgement is made explict, the end results are intuitively
reasonable and the methodology apparently acceptable to decision makers. 相似文献
980.
煤层自燃后产生"热剩磁",基于这一理论,运用地面高精度磁测在灵武某煤田对煤田自燃区的边界范围进行圈定.由钻孔验证的结果来看,地面高精度磁测在圈定煤田自燃区边界范围时效果良好. 相似文献