全文获取类型
收费全文 | 29304篇 |
免费 | 639篇 |
国内免费 | 5596篇 |
专业分类
安全科学 | 1292篇 |
废物处理 | 1533篇 |
环保管理 | 2819篇 |
综合类 | 11364篇 |
基础理论 | 5985篇 |
环境理论 | 10篇 |
污染及防治 | 8918篇 |
评价与监测 | 1671篇 |
社会与环境 | 1259篇 |
灾害及防治 | 688篇 |
出版年
2023年 | 280篇 |
2022年 | 807篇 |
2021年 | 650篇 |
2020年 | 482篇 |
2019年 | 525篇 |
2018年 | 734篇 |
2017年 | 857篇 |
2016年 | 988篇 |
2015年 | 1078篇 |
2014年 | 1558篇 |
2013年 | 2663篇 |
2012年 | 1707篇 |
2011年 | 1921篇 |
2010年 | 1420篇 |
2009年 | 1470篇 |
2008年 | 1587篇 |
2007年 | 1508篇 |
2006年 | 1362篇 |
2005年 | 1104篇 |
2004年 | 868篇 |
2003年 | 1006篇 |
2002年 | 923篇 |
2001年 | 995篇 |
2000年 | 797篇 |
1999年 | 736篇 |
1998年 | 568篇 |
1997年 | 521篇 |
1996年 | 509篇 |
1995年 | 478篇 |
1994年 | 425篇 |
1993年 | 325篇 |
1992年 | 317篇 |
1991年 | 261篇 |
1990年 | 244篇 |
1989年 | 198篇 |
1988年 | 207篇 |
1987年 | 132篇 |
1986年 | 158篇 |
1985年 | 148篇 |
1984年 | 146篇 |
1983年 | 139篇 |
1982年 | 139篇 |
1981年 | 146篇 |
1980年 | 96篇 |
1979年 | 103篇 |
1978年 | 106篇 |
1976年 | 95篇 |
1974年 | 106篇 |
1967年 | 101篇 |
1964年 | 92篇 |
排序方式: 共有10000条查询结果,搜索用时 125 毫秒
881.
运用地图学的理论和方法,阐述了灾害地图的性质、内容、功能和作用,介绍了灾害地图的主要类型,探讨了灾害信息图形显示的过程、方法和手段,并提出了开展灾害地图研究的几点建议。 相似文献
882.
喷射溶气回流浮选工艺处理含油废水 总被引:8,自引:0,他引:8
采用喷射溶气回流浮选工艺处理含油废水,替代原来的全加压溶气浮选工艺,提高了浮选过程的处理效果,增强了系统的抗负荷冲击能力,浮选出水油含量由原来的〈40mg/L降至〈20mg/L,COD由原来的〈150mg/L降至〈110mg/L。 相似文献
883.
Activated carbon, developed from fertilizer waste, has been used for the removal of Hg2+, Cr6+, Pb2+, and Cu2+. Mass transfer kinetic approach has been successfully applied for the determination of various parameters necessary for designing a fixed-bed absorber. Parameters selected are the length of the (PAZ) primary adsorption zone (δ), total time involved for the establishment of primary adsorption zone (tx), mass rate of flow to the absorber (Fm), time for primary adsorption zone to move down its length (tδ), amount of adsorbate adsorbed in PAZ from breakpoint to exhaustion (Ms), fractional capacity (f), time of initial formation of PAZ (tf) and per cent saturation of column at break point. Chemical regeneration has been achieved with 1 M HNO3. 相似文献
884.
There are numerous technologies currently being tested by EPA, universities throughout the world, and private research organizations. A few of the more promising innovative technologies as well as fully tested and proven remedies for treating contaminated groundwater are presented in this article. Although several of those technologies have been in existence for only four to five years, the results of full-scale testing are being produced. The method for each of these promising technologies is described, results from recent field-scale studies are summarized, and a discussion of cost is presented. 相似文献
885.
防辐射有机玻璃板材的抗辐射性能 总被引:7,自引:0,他引:7
系统研究了含铅有机玻璃、含钡有机玻璃、含硼有机玻璃和普通有机玻璃的x、γ射线和中子射线防护性能及其耐60Cγ射线辐照稳定性。结果表明,含铅有机玻璃板材具有良好的x射线、反应堆热柱γ射线屏蔽性能;合硼有机玻璃板材具有良好的热中子屏蔽性能;含钡有机玻璃板材的褪化裂变谱中子辐射屏蔽性能良好;含钡有机玻璃和普通有机玻璃可耐105~106Gy的60Coy射线辐照;含铅有机玻璃板材耐60Coy射线照射能力小于105Gy。 相似文献
886.
Characteristics of large cooking oil pool fires and their extinguishment by water mist 总被引:1,自引:0,他引:1
Z. Liu D. Carpenter A.K. Kim 《Journal of Loss Prevention in the Process Industries》2006,19(6):516-526
Large cooking oil pool fires, occurring in industrial oil cookers, present a severe hazard to food processing plants due to their size and the large amount of hot oil involved. This paper reports a series of full-scale fire experiments conducted in a large industrial oil cooker mock-up. The characteristics of large cooking oil pool fires and the effect of oil depth and hood position in the oil cooker on fire growth were studied. The use of water mist for extinguishing large oil pool fires and their extinguishing performance under different discharge pressure and with different types of water mist systems were investigated. Experimental results showed that the cooking oil underwent a substantial expansion in volume during heating. The fires developed quickly once the oil auto-ignited. The fire growth rate was affected by the oil depth in the pan and the hood position in the oil cooker. The water mist fire suppression systems effectively extinguished large cooking oil fires and prevented them from re-igniting. Their extinguishing performance was determined by the type of water mist system, discharge pressure and hood position in the oil cooker. 相似文献
887.
Explosive gas mixtures and explosive dust clouds, once existing, exhibit similar ignition and combustion features. However, there are two basic differences between dusts and gases which are of substantially greater significance in design of safety standards than these similarities. Firstly, the physics of generation and up-keeping of dust clouds and premixed gas/vapour clouds are substantially different. This means that in most situations where accidental explosive gas clouds may be produced quite readily, generation of explosive dust clouds would be highly unlikely. Secondly, contrary to premixed gas flame propagation, the propagation of flames in dust/air mixtures is not limited only to the flammable dust concentration range of dynamic clouds. The state of stagnant layers/deposits offers an additional discrete possibility of flame propagation.
The two European Directives 94/9/EC (1994) and 1999/92/EC (1999) primarily address gases/vapours, whereas the particular properties of dusts are not addressed adequately. Some recent IEC and European dust standards resulting from this deficiency are discussed, and the need for revising the two directives accordingly is emphasized. 相似文献
888.
Biswajit Ruj Imranur Rehman A.K. Bandyopadhya 《Journal of Loss Prevention in the Process Industries》2006,19(6):645-647
After Bhopal disaster, emergency planning in an industrial area has become inevitable. The off-site emergency plan is an integral part of any major hazard control system. Boiling Liquid Expanding Vapour Explosion (BLEVE) leads to fatal consequences. This paper highlights some salient features of the emergency scenario, which ultimately leads to fireball with enormous pressure wave all around. 相似文献
889.
应规范用人单位内部调职行为 总被引:2,自引:0,他引:2
用人单位内部调职是指在同一用人单位内,长期性的变更劳动者的工作场所、工作内容的用人单位的行为.长期性的变更是用人单位内部调职的重要特征,并因此与出差区别开来. 相似文献
890.
The New Jersey Toxics Reduction Workplan for Ny-Nj Harbor: Distribution of Pcdd/Fs in Ambient Waters
As part of the NJ Toxics Reduction Workplan for NY-NJ Harbor, ambient water samples were collected at fifteen locations along
the tidal portions of the Hackensack, Passaic, Raritan, Rahway and Elizabeth Rivers, and in Newark Bay, the Arthur Kill, and
Kill van Kull. A Trace Organics Platform Sampler was used to collect a total of 75 suspended sediment phase samples between
June 2000 and May 2002. These samples were analyzed for spatial and wet vs. dry weather trends in the 17 polychlorinated dibenzo-p-dioxins
and dibenzofurans (PCDD/Fs; modified USEPA Method 1613b). Mean total PCDD/F (tPCDD/F) concentrations at the sampling locations
ranged between 3.8 and 41.5 ng/g. On average, OCDD accounted for almost 80% of the tPCDD/F concentrations; mean total [PCDD/F
– OCDD] concentrations ranged between 0.84 and 5.20 ng/g at the sampling locations. Mean 2,3,7,8-TCDD concentrations ranged
between 0.003 and 0.28 ng/g, with the highest concentrations (> 0.10 ng/g) along the tidal Passaic and lower Hackensack Rivers,
and in upper Newark Bay. Mean tPCDD/F Toxic Equivalency Quotients (TEQ) ranged between 45 and 344 TEQ pg/g, with the highest
levels found in the lower Passaic River. Toxicity was primarily driven by 2,3,7,8-TCDD concentrations in the Passaic and Hackensack
Rivers, and in Newark Bay. Examples of congener distribution patterns at some of the sampling locations are also presented. 相似文献