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991.
Qiang Liu Mi Li Rong Chen Zhengyue Li Guangren Qian Taicheng An Jiamo Fu Guoying Sheng 《Waste management (New York, N.Y.)》2009,29(7):2051-2058
An in situ compost biofilter was established for the treatment of odors from biostabilization processing of municipal solid waste. The concentrations of total volatile organic compounds (VOCs) in odors and their components were measured. Biofilter media was characterized in terms of total carbon (TC), total nitrogen (TN), total phosphorus (TP), organic matter (OM), pH value and determination of bacterial colony structure. Gas chromatography–mass spectrometry (GC–MS) analysis showed that the main components of the produced gas were benzene, toluene, ethylbenzene and xylene (BTEX) along with other alkanes, alkenes, terpenes, and sulphur compounds. The compost biofilter had remarkable removal ability for alkylated benzenes (>80%), but poor removal for terpenes (~30%). Total VOC concentrations in odors during the biostabilization process period ranged from 0.7 to 87 ppmv, and the VOC removal efficiency of the biofilter varied from 20% to 95%. After about 140 days operation, TN, TC, TP and OM in compost were kept almost stable, but the dissolved N, NH4–N and NO3–N experienced an increase of 44.5%, 56.2% and 76.3%, respectively. Dissolved P decreased by 27.3%. The pH value experienced an increase in the early period and finally varied from 7.38 to 8.08. Results of bacterial colony in packing material indicated that bacteria and mold colony counts increased, but yeasts and actinomyces decreased along with biofilter operation, which were respectively, 3.7, 3.4, 0.04 and 0.07 times of their initial values. 相似文献
992.
The increasing volume of CO2 embodiment in international trade adds a layer of complexity to environmental policies and has raised arguments on the traditional production based responsibility for CO2 emissions. In order to help understand the quantity of CO2 embodiment in trade and its policy implications, this paper gives observations to recently emerging literatures that quantitatively discuss CO2 embodiment in trade. The analytical approaches share the principle of using input and output modeling but vary dramatically in study boundary and estimation accuracy. The calculations can be roughly categorized into three types: direct quantification of CO2 embodiments in multiregional trade, direct quantification of CO2 embodiment in bilateral trade, and indirect analysis by comparing the scenarios with or without trade. The practical estimations strongly rely on trade partner selection and data availability. An obvious imbalance of net CO2 embodiment in the commodity trade between major developed countries and developing economies as a whole was confirmed by these literatures. Carbon taxes and other possible limitations on CO2 emissions have been addressed. The consistency across the calculations could be enhanced by systematic analyses in more detail to convince the international community to take binding commitments for the reduction of global CO2 emissions. 相似文献
993.
994.
考虑离散油滴在油田废水除油过程中发生的油滴碰撞聚结现象,模拟得出斜板除油器内全部油滴的动态信息,用于斜板除油器除油效率的计算.对矩形同向流斜板除油过程的模拟研究表明:油滴的碰撞聚结会增加斜板除油的效率;当废水的原始含油浓度增大时,斜板除油的效率会增大,碰撞聚结对除油效率提高的影响也越大;废水流动速度提高及斜板的倾斜角度增加均会使斜板的除油效率降低,但此时油滴碰撞聚结对除油效率的影响仍很明显. 相似文献
995.
大气光化学烟雾反应机理比较(Ⅰ)O3和NOx的比较 总被引:8,自引:0,他引:8
在相同初始和排放条件下,对四种应用较广的光化学烟雾反应机理(CB4-99,RADM2,RACM,SAPRC99)进行了比较.研究发现对于O3,在低VOCs/NOx时,四种机理模拟结果相关较小,平均相对标准偏差为7%,在高VOCs/NOx时,平均相对标准偏差为26%,差距较大;对于NOx,多数情况下RACM和RADM2的模拟结果较高,CB4-99和SAPRC99的模拟值偏低,其原因主要来源于不同机理中O3的生成对NOx及VOCs的敏感性不同而造成的.在用模式模拟O3和NOx时,应特别注意机理不同而带来的模拟结果差异. 相似文献
996.
自然资源利用权从产生的途径上看应属于特许物权,从内容和功能上看应属于准用益物权,两种物权属性并不相互排斥。自然资源利用权的双重物权属性符合环境保护的价值取向和价值选择。 相似文献
997.
998.
Zhi-Ping Wang Yang Song Jay Gulledge Qiang Yu Hong-Sheng Liu Xing-Guo Han 《Atmospheric environment (Oxford, England : 1994)》2009,43(13):2148-2153
A budget for the methane (CH4) cycle in the Xilin River basin of Inner Mongolia is presented. The annual CH4 budget in this region depends primarily on the sum of atmospheric CH4 uptake by upland soils, emission from small wetlands, and emission from grazing ruminants (sheep, goats, and cattle). Flux rates for these processes were averaged over multiple years with differing summer rainfall. Although uplands constitute the vast majority of land area, they consume much less CH4 per unit area than is emitted by wetlands and ruminants. Atmospheric CH4 uptake by upland soils was ?3.3 and ?4.8 kg CH4 ha?1 y?1 in grazed and ungrazed areas, respectively. Average CH4 emission was 791.0 kg CH4 ha?1 y?1 from wetlands and 8.6 kg CH4 ha?1 y?1 from ruminants. The basin area-weighted average of all three processes was 6.8 kg CH4 ha?1 y?1, indicating that ruminant production has converted this basin to a net source of atmospheric CH4. The total CH4 emission from the Xilin River basin was 7.29 Gg CH4 y?1. The current grazing intensity is about eightfold higher than that which would result in a net zero CH4 flux. Since grazing intensity has increased throughout western China, it is likely that ruminant production has converted China's grazed temperate grasslands to a net source of atmospheric CH4 overall. 相似文献
999.
基于GIS的耕地土壤重金属污染与农业功能定位研究——以山东省聊城市为例 总被引:1,自引:0,他引:1
按8km×8km的网格将聊城市耕地分为137个采样点,调查砷、镉、铬、铜、汞、镍、铅、锌等重金属的污染状况。采用国家土壤环境质量标准、农产品安全质量标准和绿色食品产地环境条件作为评价标准,采用单因子指数和综合指数为评价方法进行污染评价。研究表明,聊城市土壤污染强度依次为铜〉镍〉锌〉砷〉铬〉镉〉铅〉汞,但均未超标。以GIS为操作平台显示聊城市重金属空间分布状况,并对区域耕地进行了功能的定位。聊城市西南部土壤质量最优,适宜种植绿色食品;无公害蔬菜和安全粮食种植区在各县市均有不同程度的分布。 相似文献
1000.
国民信息素养的高低已成为一个国家在全球竞争中获得优势地位的关键,信息素养教育在全世界范围内备受重视。本文以信息素养为出发点,以当今高校对在校大学生信息素养培训的新要求为依据,通过信息的选择、检索、利用,个人创新和文化素养等五个方面的教育,论述了如何培养高校学生信息素养,使学生养成终身学习的习惯。 相似文献