全文获取类型
收费全文 | 2395篇 |
免费 | 267篇 |
国内免费 | 832篇 |
专业分类
安全科学 | 444篇 |
废物处理 | 23篇 |
环保管理 | 277篇 |
综合类 | 1818篇 |
基础理论 | 256篇 |
环境理论 | 1篇 |
污染及防治 | 176篇 |
评价与监测 | 163篇 |
社会与环境 | 242篇 |
灾害及防治 | 94篇 |
出版年
2024年 | 28篇 |
2023年 | 83篇 |
2022年 | 154篇 |
2021年 | 206篇 |
2020年 | 129篇 |
2019年 | 159篇 |
2018年 | 113篇 |
2017年 | 150篇 |
2016年 | 181篇 |
2015年 | 175篇 |
2014年 | 144篇 |
2013年 | 210篇 |
2012年 | 201篇 |
2011年 | 248篇 |
2010年 | 146篇 |
2009年 | 136篇 |
2008年 | 137篇 |
2007年 | 165篇 |
2006年 | 144篇 |
2005年 | 110篇 |
2004年 | 87篇 |
2003年 | 84篇 |
2002年 | 73篇 |
2001年 | 45篇 |
2000年 | 31篇 |
1999年 | 21篇 |
1998年 | 21篇 |
1997年 | 20篇 |
1996年 | 20篇 |
1995年 | 12篇 |
1994年 | 10篇 |
1993年 | 11篇 |
1992年 | 8篇 |
1991年 | 3篇 |
1990年 | 5篇 |
1989年 | 6篇 |
1988年 | 1篇 |
1986年 | 2篇 |
1985年 | 1篇 |
1982年 | 2篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1979年 | 3篇 |
1977年 | 1篇 |
1974年 | 2篇 |
1973年 | 1篇 |
1972年 | 2篇 |
1971年 | 1篇 |
排序方式: 共有3494条查询结果,搜索用时 15 毫秒
971.
近年来随着成品油价格的不断上涨,大庆油田及其周边地区不少不法分子在利益驱动下,利用简易的土法炼制设备从事非法炼油活动。为了更加有效地依法治理非法炼油活动,大庆油田对其存在的原因及危害进行了分析与探讨,并采取了有效措施,达到了环境与效益双赢的目的。 相似文献
972.
Promoting stoves that burn wood and other biofuels more efficiently is one of the means to reduce fuel consumption, but such efficient stoves may also emit more carbon monoxide and total suspended particulates. In an earlier study, a standard chamber method was proposed to estimate emission factors from burning fuelwood (Acacia nilotica). Here that methodology is extended to measure emission factors from burning of dungcakes and crop residues (Brassica or mustard stalks)—common fuels in many developing countries. The amounts of carbon monoxide (CO) and total suspended particulates (TSP) emitted by four different models of stoves, when using each of the three biofuels, are measured.The CO emission factors range from 13–68 (g/kg) for fuelwood to 26–67 g/kg for dungcakes and 20–114 g/kg for crop residues, for particulates they range from 1.1–3.8 to 4.1–7.8 and 2.1–12.0 g/kg for the three fuels, respectively. On a per unit heat delivered basis, the emissions of CO and TSP from both dungcakes and crop residues are two to three times higher compared to those from fuelwood. While for some improved stove-fuel combinations, the increase in emission factors was offset by the increase in thermal efficiency, this was not always so and causes a dilemma. The more efficient stoves are found to have higher emission factors of both CO and TSP for all three fuels. Emissions per standard task (i.e, on a unit heat delivered basis) is proposed as a criterion to evaluate cookstoves. 相似文献
973.
气象和环境对装备的影响及适应性对策 总被引:4,自引:1,他引:3
气象条件、环境条件对飞机空中飞行作战有着至关重要的影响。为了提高新时期我军的战斗力,就必须做好新型武器装备的防护,制定出切实有效的防护措施,有效发挥我军新型战机作战效能。 相似文献
974.
975.
实行国有大中型企业扭亏解困,其核心是抓大放小,采取改组、联合、兼并、租赁和股份制等形式,真正建立产权明晰、权责明确、政企分开、管理科学的现代企业制度。因此企业改制会对环境管理工作带来广泛而深刻的影响,同时环境管理工作也面临许多机遇和挑战。江钻股份公司在企业改制过程中积极探索,大胆实践,创造出一条环境管理的新路子。 相似文献
976.
977.
新疆油气田开发对环境的影响及其对策 总被引:4,自引:0,他引:4
该文论述了新疆油气田开发对大气环境,土壤,地下水以及生态环境的不同程度的影响,重点论述了对生态环境的影响,并提出了一些对策和建议,这些对新疆乃至对全国的油气田环境保护工作都具有一定的参考和借鉴作用。 相似文献
978.
系统分析、核定了沈阳市铁西区水污染物排放总量,通过对排污总量的可靠性分析和度量,提出了提高系统信息可靠性的监测与改进建议.认为加强泵站信息的监测与调查有利于对重金属类污染物实施总量控制;而且,在此基础上追加细河黄蜡坨子断面的监测不仅可以清晰识别细河入浑河的排污量,而且可以对有机污染物进行总量控制作出有针对性的、及时的反应. 相似文献
979.
980.
H. Wingfors . Sjdin P. Haglund E. Brorstrm-Lundn 《Atmospheric environment (Oxford, England : 1994)》2001,35(36)
The concentrations of semi-volatile polycyclic aromatic hydrocarbons (PAHs), hydrocarbons (HCs), particulate matter (PM 1, 2.5 and 10 μm) and total suspended particles (TSPs) were measured in a traffic tunnel in Gothenburg, Sweden. Emission factors (EFs) were also calculated. These variables are assumed to provide good estimates of average vehicle emissions, since all types of vehicle, using all types of fuel, pass through this tunnel. It was shown that the majority of particle-associated PAHs were found on particles with an aerodynamic diameter of <1 μm. The concentrations of PAHs were one order higher in magnitude in air samples from the tunnel than in air samples at two urban locations. However, the PAH profiles of air samples from the tunnel and the urban sites were similar. This was demonstrated using principal component analysis (PCA). Finally, and notably, there was no significant change in the total emissions when the proportion of heavy-duty vehicles (HDVs) increased from 8% to 24%. Previously, diesel vehicles had been found to release larger quantities of PAHs and related substances. Advances in fuel quality, and HDV motor and exhaust system design during the last decade may have contributed to this promising result. However, it was shown, using partial least squares regression to latent structures (PLS), that some of the parameters measured displayed correlations with the proportions of HDVs and light-duty vehicles (LDVs). Concentrations of total HCs, TSPs, dibenzothiopene, phenantrene, anthracene and monomethyl-derivatives of phenantrene and anthracene were all correlated to the proportion of HDVs. The concentrations of naphthalene, some mono- and dimethylnaphthalenes and most large PAHs (with 5–7 fused rings) were correlated to the proportion of LDVs. 相似文献