全文获取类型
收费全文 | 2317篇 |
免费 | 18篇 |
国内免费 | 94篇 |
专业分类
安全科学 | 112篇 |
废物处理 | 214篇 |
环保管理 | 298篇 |
综合类 | 306篇 |
基础理论 | 404篇 |
环境理论 | 1篇 |
污染及防治 | 805篇 |
评价与监测 | 199篇 |
社会与环境 | 75篇 |
灾害及防治 | 15篇 |
出版年
2023年 | 11篇 |
2022年 | 34篇 |
2021年 | 36篇 |
2020年 | 12篇 |
2019年 | 42篇 |
2018年 | 73篇 |
2017年 | 58篇 |
2016年 | 80篇 |
2015年 | 55篇 |
2014年 | 69篇 |
2013年 | 186篇 |
2012年 | 130篇 |
2011年 | 150篇 |
2010年 | 101篇 |
2009年 | 131篇 |
2008年 | 141篇 |
2007年 | 151篇 |
2006年 | 132篇 |
2005年 | 115篇 |
2004年 | 110篇 |
2003年 | 99篇 |
2002年 | 90篇 |
2001年 | 66篇 |
2000年 | 36篇 |
1999年 | 24篇 |
1998年 | 20篇 |
1997年 | 24篇 |
1996年 | 20篇 |
1995年 | 18篇 |
1994年 | 18篇 |
1993年 | 19篇 |
1992年 | 10篇 |
1991年 | 19篇 |
1990年 | 10篇 |
1989年 | 9篇 |
1988年 | 10篇 |
1986年 | 7篇 |
1985年 | 9篇 |
1984年 | 7篇 |
1983年 | 8篇 |
1982年 | 10篇 |
1981年 | 11篇 |
1980年 | 10篇 |
1978年 | 6篇 |
1976年 | 5篇 |
1974年 | 4篇 |
1973年 | 5篇 |
1972年 | 6篇 |
1971年 | 6篇 |
1969年 | 5篇 |
排序方式: 共有2429条查询结果,搜索用时 15 毫秒
901.
902.
903.
Hsi-Hsien Yang Shao-Wei Luo Kuei-Ting Lee Jhin-Yan Wu Chun Wei Chang Pei Feng Chu 《Journal of the Air & Waste Management Association (1995)》2016,66(8):807-814
In this study, fine particulate matter (PM2.5) emitted from a municipal solid waste incinerator (MSWI) was collected using dilution sampling method. Chemical compositions of the collected PM2.5 samples, including carbon content, metal elements, and water-soluble ions, were analyzed. Traditional in-stack hot sampling was simultaneously conducted to compare the influences of dilution on PM2.5 emissions and the characteristics of the bonded chemical species. The results, established by a dilution sampling method, show that PM2.5 and total particulate matter (TPM) emission factors were 61.6 ± 4.52 and 66.1 ± 5.27 g ton-waste?1, respectively. The average ratio of PM2.5/TPM is 0.93, indicating that more than 90% of PM emission from the MSWI was fine particulate. The major chemical species in PM2.5 included organic carbon (OC), Cl?, NH4+, elemental carbon (EC) and Si, which account for 69.7% of PM2.5 mass. OC was from the unburned carbon in the exhaust, which adsorbed onto the particulate during the cooling process. High Cl? emission is primarily attributable to wastes containing plastic bags made of polyvinyl chloride, salt in kitchen refuse and waste biomass, and so on. Minor species that account for 0.01–1% of PM2.5 mass included SO42-, K+, Na, K, NO3?, Al, Ca2+, Zn, Ca, Cu, Fe, Pb, and Mg. The mean ratio of dilution method/in-stack hot method was 0.454. The contents of water-soluble ions (Cl?, SO42-, NO3?) were significantly enriched in PM2.5 via gas-to-particle conversion in the dilution process. Results indicate that in-stack hot sampling would underestimate levels of these species in PM2.5.Implications: PM2.5 samples from a municipal solid waste incinerator (MSWI) were collected simultaneously by a dilution sampling technique and a traditional in-stack method. PM2.5 emission factors and chemical speciation profiles were established. Dilution sampling provides more reliable data than in-stack hot sampling. The results can be applied to estimate the PM2.5 emission inventories of MSWI, and the source profile can be used for contribution estimate of chemical mass balance modeling. 相似文献
904.
The current conceptual hydrogeologic model established for source water to the Amargosa River was tested in order to help inform management decisions regarding the Amargosa River's Federal designation as Wild and Scenic through an Act of Congress. The limited availability of water in this region results in the critical need for effective management in the basin to maintain its Wild and Scenic attributes inclusive of habitat for several endangered and threatened species. The use of forensic tools and integration of multiple lines of geologic, hydrogeologic, geochemical, and stable isotopic evidence suggest that the simple historical model for primary groundwater transport through this region is incorrect and that a large supply of regional baseflow does not provide the hydrogeological foundation of the Amargosa River basin. Data collected is consistent with an alternative model requiring complex source mixing and shallow alluvial groundwater that supports river flow. This conclusion also suggests Wild and Scenic conditions in this basin are more precarious than previously understood. 相似文献
905.
906.
Effects of acid and nitrogen depositions on soil microbial activities were studied in a laboratory-based experiment. Five treatments were added to forest soil for five weeks, and soil enzyme activities were determined along with chemical properties. There was little change in pH and nitrogen availability. Dehydrogenase, phosphatase and arylsulphatase activities were decreased by all the acidic treatments compared to the control, while urease activity was increased by the pH 4 treatment. at the same pH treatment, different nitric acid contents induced different urease activities. the results suggest that acid deposition would inhibit microbial activities and that more study is needed to elucidate the impact on nitrogen cycling in forests. 相似文献
907.
Dwight R Lee 《Journal of Environmental Economics and Management》1975,2(1):69-72
This paper looks at the performance of a uniform pollution tax in achieving a given level of pollution abatement at least cost. It is shown that market structure is an important consideration in this performance and that in general least-cost abatement will not result from a pollution tax uniformly applied. The pattern of pollution taxes that will achieve least-cost abatement when differing degrees of market power exist among polluters is developed and discussed. 相似文献
908.
D. Pimentel N. Brown F. Vecchio V. La Capra S. Hausman O. Lee A. Diaz J. Williams S. Cooper E. Newburger 《Journal of Agricultural and Environmental Ethics》1992,5(2):113-146
Burning fossil fuel in the North American continent contributes more to the CO2 global warming problem than in any other continent. The resulting climate changes are expected to alter food production. The overall changes in temperature, moisture, carbon dioxide, insect pests, plant pathogens, and weeds associated with global warming are projected to reduce food production in North America. However, in Africa, the projected slight rise in rainfall is encouraging, especially since Africa already suffers from severe shortages of rainfall. For all regions, a reduction in fossil fuel burning is vital. Adoption of sound ecological resource management, especially soil and water conservation and the prevention of deforestation, is important. Together, these steps will benefit agriculture, the environment, farmers, and society as a whole. 相似文献
909.
The rationale and outline of an implementation plan for restoring coastal wetlands in Louisiana is presented. The rationale
for the plan is based on reversing the consequences of documented cause-and-effect relationships between wetland loss and
hydrologic change. The main feature is to modify the extensive interlocking network of dredged spoil deposits, or spoil banks,
by reestablishing a more natural water flow at moderate flow velocity (<5 cm/sec). Guidelines for site selection from thousands
of potential sites are proposed. Examples of suitable sites are given for intermediate marshes. These sites exhibit rapid
deterioration following partial or complete hydrologic impoundment, implying a strong hydrologic, rather than sedimentological,
cause of wetland deterioration.
We used an exploratory hydrologic model to guide determination of the amount of spoil bank to be removed. The results from
an economic model indicated a very effective cost-benefit ratio. Both models and practical experience with other types of
restoration plans, in Louisiana and elsewhere, exhibit an economy of scale, wherein larger projects are more cost effective
than smaller projects. However, in contrast to these other projects, spoil bank management may be 100 to 1000 times more cost
effective and useful in wetland tracts <1000 ha in size. Modest spoil bank management at numerous small wetland sites appears
to offer substantial positive attributes compared to alternative and more intensive management at a few larger wetland sites. 相似文献
910.
John G. Lee John R. Ellis Ronald D. Lacewell 《Journal of the American Water Resources Association》1985,21(3):441-447
This paper presents estimates made via a recursive linear programming model of the net benefits of improving irrigation application efficiency from an exhaustible groundwater source. Net benefits were derived for different application efficiency levels under furrow, sprinkler, and LEPA irrigation systems. In addition, net benefit estimates were obtained for the transition across irrigation systems. Solutions from the model indicate that low crop prices have a differential impact on net benefits across irrigation application efficiencies and irrigation systems. Also, the more limited groundwater situations consistently reduce the economic incentive to adopt improved irrigation application techniques across all irrigation systems. 相似文献