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911.
Andrew M. Crowe Ai Sakata Colin McClean Malcolm S. Cresser 《Water, Air, & Soil Pollution: Focus》2004,4(6):75-84
Factors influencing soil profile nitrogen storage (SPNS) in GB have been investigated. The SPNS values of moorland peats and podzols in the South Pennines, of permanent grassland in Yorkshire, and of adjacent arable-, semi-permanent grassland- and ancient woodland-soils in Worcestershire have been compared to assess land use effects. The soils exhibited similar SPNS values, because changes in bulk density and organic matter composition offset increases in N concentrations in highly organic soils. Data from the Soil Survey of Scotland were used to show effects of soil parent material on SPNS were also small. Data on Scottish podzol soils under heather moorland and derived from sandstone or quartzite were used to show that SPNS declined with increasing precipitation, but increased with the amount of pollutant N deposited from the atmosphere. 相似文献
912.
从社会变革看我国事故频发的管理根源——价值缺陷导致的管理失灵分析 总被引:1,自引:3,他引:1
如何认识和解决我国事故高发问题始于20世纪90年代,至今仍未得到很好地解决,已成为社会广泛关注的焦点。笔者以探索事故高发的管理根源为目的,对我国目前事故高发问题即“安全管理的困惑”从不同方面、不同层次上的具体表现进行了分析,将其寓于我国社会经济变革的大背景进行认识,从安全管理的哲学层次和我国社会经济变革的发展中研讨“事故高发、频发”的管理根源,分别从安全科学理论、世界社会经济发展的历史以及安全管理层次及其相互联系的角度,对我国事故高发问题进行了全面论述,提出了哲学文化层次带来的问题是产生“管理困惑”的源头。从整体上来看,我国事故高发、频发的管理根源在于:社会经济变革条件下产生的,由价值缺陷导致的“管理失灵”。“管理失灵”是问题的表现形式和结果,社会经济变革产生的“价值缺陷”是问题的核心。 相似文献
913.
An Aquifer Storage and Recovery system with reclaimed wastewater to preserve native groundwater resources in El Paso, Texas 总被引:3,自引:0,他引:3
Sheng Z 《Journal of environmental management》2005,75(4):367-377
The traditional concept of Aquifer Storage and Recovery (ASR) has been emphasized and extensively applied for water resources conservation in arid and semi-arid regions using groundwater systems as introduced in Pyne's book titled Groundwater Recharge and Wells. This paper extends the ASR concept to an integrated level in which either treated or untreated surface water or reclaimed wastewater is stored in a suitable aquifer through a system of spreading basins, infiltration galleries and recharge wells; and part or all of the stored water is recovered through production wells, dual function recharge wells, or by streams receiving increased discharge from the surrounding recharged aquifer as needed. In this paper, the author uses the El Paso Water Utilities (EPWU) ASR system for injection of reclaimed wastewater into the Hueco Bolson aquifer as an example to address challenges and resolutions faced during the design and operation of an ASR system under a new ASR system definition. This new ASR system concept consists of four subsystems: source water, storage space-aquifer, recharge facilities and recovery facilities. Even though facing challenges, this system has successfully recharged approximately 74.7 million cubic meters (19.7 billion gallons) of reclaimed wastewater into the Hueco Bolson aquifer through 10 recharge wells in the last 18 years. This ASR system has served dual purposes: reuse of reclaimed wastewater to preserve native groundwater, and restoration of groundwater by artificial recharge of reclaimed wastewater into the Hueco Bolson aquifer. 相似文献
914.
存域网(SAN)在数字图书馆中信息安全的应用研究 总被引:2,自引:0,他引:2
数字图书馆是图书馆信息化建设的必然趋势 ,通过采用存域网 (SAN ,StorageAreaNetwork)技术 ,可以保证图书馆数据信息的可靠与安全 ,笔者分析了根据不同的需求 ,采用不同的SAN拓扑结构 ,为图书馆信息网络建设提供了多种可靠的解决方案 相似文献
915.
Kenneth O. Kauffman 《Journal of the American Water Resources Association》1979,15(2):387-395
ABSTRACT: In many of the limited water resource areas of the western United States most water supplies have been put to beneficial uses. Energy, a fast expanding high-priority water use, is making challenging demands for these limited supplies. Can water supplies be stretched, supplemented, or redirected so that present uses can be maintained and energy water needs satisfied? The Bureau of Reclamation is investigating innovative methods of water management, reregulation, and use to meet these demands. Related programs under study include potentials for: development of additional hydroelectric power, installation of low-head turbines in western water courses, utilization of pumped storage and underground storage, use of geo-thermal heat, extension of water supplies through more efficient irrigation systems and practices, and weather modification. 相似文献
916.
液化石油气储存和管道输送安全 总被引:3,自引:0,他引:3
系统地分析了液化石油气的危险性,并给出了有代表性的事故案例,在此基础上,提出了必要的事故预防措施及应急救援中应注意的问题,对于液化石油气储存安全和管道输送安全有重要的参考价值。 相似文献
917.
918.
The Dutch Working Party on Prenatal Diagnosis has initiated a study on the possibilities of first-trimester screening for fetal chromosomal disorders. We report on maternal serum human chorionic gonadotrophin (MS-hCG) measurements in 1348 pregnancies with a chromosomally normal fetus and 53 pregnancies with a chromosomally abnormal fetus. The median MS-hCG concentration in 24 pregnancies with Down's syndrome was 1.19 multiples of the normal median (MoM). The MS-hCG distributions in normal and Down's syndrome pregnancies did not differ significantly (t-test: t = 1.945, p >0.05). We also found no difference between normal pregnancies and pregnancies with other chromosomal disorders (six cases of trisomy 18, MoM = 0.80; four cases of sex chromosome abnormality, MoM = 1.01; 17 cases of chromosomal mosaicism in chorionic villi, MoM = 1.11). Selecting an upper limit at the 90th centile could detect 25 per cent of pregnancies with Down's syndrome. We conclude that, in the first trimester, MS-hCG as a screening factor for Down's syndrome is of minor value. However, MS-hCG could be a useful factor in a first-trimester screening programme based on a combination of markers. 相似文献
919.
Thomas J. Simpson Mitsuhiko Koresawa W. Allen Hogge Wolfgang Holzgreve Dr. Mitchell S. Golbus 《黑龙江环境通报》1987,7(9):639-652
A reliable and sensitive microassay for the measurement of liver glucose-6-phosphatase is described. Human fetal liver was assayed for glucose-6-phosphatase activity from 7.5 to 24 weeks of gestation and was found to have a mean activity of 2.11 nmol per min per mg of protein. This was approximately 30 per cent of the postnatal controls assayed by the same method, but there was no evidence of a change in activity during the gestational period examined. If fetal liver tissue can be reliably obtained, it may be possible to determine a deficiency of glucose-6-phosphatase in fetuses who are at risk. 相似文献
920.
Moura Costa Pedro Wilson Charlie 《Mitigation and Adaptation Strategies for Global Change》2000,5(1):51-60
Concern about the issue of permanence andreversibility of the effects of carbon sequestrationhas led to the need to devise accounting methods thatquantify the temporal value of storing carbon that hasbeen actively sequestered or removed from theatmosphere, as compared to carbon stored as a resultof activities taken to avoid emissions. This paperdescribes a method for accounting for the atmosphericeffects of sequestration-based land-use projects inrelation to the duration of carbon storage. Firstly,the time period over which sequestered carbon shouldbe stored in order to counteract the radiative forcingeffect of carbon emissions was calculated, based onthe residence time and decay pattern of atmosphericCO2, its Absolute Global Warming Potential. Thistime period was called the equivalence time, andwas calculated to be approximately 55 years. From thisequivalence time, the effect of storage of 1 tCO2 for 1 year was derived, and found to besimilar to preventing the effect of the emission of0.0182 tCO2. Potential applications of thistonne.year figure, here called the equivalencefactor, are then discussed in relation to theestimation of atmospheric benefits over time ofsequestration-based land use projects. 相似文献