全文获取类型
收费全文 | 24627篇 |
免费 | 204篇 |
国内免费 | 237篇 |
专业分类
安全科学 | 648篇 |
废物处理 | 979篇 |
环保管理 | 3042篇 |
综合类 | 5057篇 |
基础理论 | 6087篇 |
环境理论 | 13篇 |
污染及防治 | 6124篇 |
评价与监测 | 1697篇 |
社会与环境 | 1272篇 |
灾害及防治 | 149篇 |
出版年
2022年 | 230篇 |
2021年 | 203篇 |
2019年 | 180篇 |
2018年 | 342篇 |
2017年 | 339篇 |
2016年 | 490篇 |
2015年 | 391篇 |
2014年 | 626篇 |
2013年 | 1780篇 |
2012年 | 762篇 |
2011年 | 1015篇 |
2010年 | 817篇 |
2009年 | 938篇 |
2008年 | 1010篇 |
2007年 | 1023篇 |
2006年 | 927篇 |
2005年 | 840篇 |
2004年 | 753篇 |
2003年 | 771篇 |
2002年 | 732篇 |
2001年 | 989篇 |
2000年 | 670篇 |
1999年 | 434篇 |
1998年 | 263篇 |
1997年 | 299篇 |
1996年 | 313篇 |
1995年 | 353篇 |
1994年 | 345篇 |
1993年 | 275篇 |
1992年 | 274篇 |
1991年 | 318篇 |
1990年 | 300篇 |
1989年 | 281篇 |
1988年 | 256篇 |
1987年 | 199篇 |
1986年 | 225篇 |
1985年 | 207篇 |
1984年 | 216篇 |
1983年 | 215篇 |
1982年 | 225篇 |
1981年 | 214篇 |
1980年 | 172篇 |
1979年 | 199篇 |
1978年 | 163篇 |
1977年 | 150篇 |
1976年 | 149篇 |
1974年 | 160篇 |
1973年 | 146篇 |
1972年 | 146篇 |
1967年 | 154篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Rajesh Bajpai Neha Karakoti D. K. Upreti 《Environmental science and pollution research international》2013,20(8):5577-5592
The present study aims to assess the level and possible sources of organic and inorganic pollutants in Mahableshwar city in Western part of India and their effect on naturally growing foliose lichen Remototrachyana awasthii (Hale & Patw.) Divakar & A. Crespo. This lichen species growing abundantly in the area was collected from eight different sites on the basis of anthropogenic activities detected in the area. The concentration of inorganic heavy metals (Al, As, Cd, Cr, Fe, Pb, Mn, and Zn) and polycyclic aromatic hydrocarbons (PAHs) were analyzed and correlated with photosynthetic pigments (Chl a, Chl b, total chlorophyll, and carotenoid) together with chlorophyll degradation and protein contents. The concentration of most of the metals at different sites was significantly greater than at the control site (P?<?0.001). The highest metal content was found at Bus Stand and Panchgani, a tourist place that experiences heavy traffic activities. The concentration of PAHs, particularly of two-and three-ringed PAHs, was also found to be the highest in samples collected at Bus Stand area. The chlorophyll degradation and protein content were found to be the most sensitive parameters to assess the vitality of lichen thallus against wide range of air pollutants. The effectiveness of R. awasthii as a biomonitor will be investigated in the near future by comparing this species with other biomonitors. 相似文献
992.
X. Q. Liang Z. Y. Nie M. M. He R. Guo C. Y. Zhu Y. X. Chen Küppers Stephan 《Environmental science and pollution research international》2013,20(10):6972-6979
One strategy to combat nitrate (NO3-N) contamination in rivers is to understand its sources. NO3-N sources in the East Tiaoxi River of the Yangtze Delta Region were investigated by applying a 15N–18O dual isotope approach. Water samples were collected from the main channel and from the tributaries. Results show that high total N and NO3-N are present in both the main channel and the major tributaries, and NO3-N was one of the most important N forms in water. Analysis of isotopic compositions (δ 18O, δD) of water suggests that the river water mainly originated from three tributaries during the sampling period. There was a wide range of δ 15N-NO3 (?1.4 to 12.4 ‰) and a narrow range of δ 18O-NO3 (3.7 to 9.0 ‰) in the main channel waters. The δ 15N and δ 18O-NO3 values in the upper, middle, and lower channels along the river were shifted as 8.2, 3.5, and 9.5 ‰, and 9.0, 4.2, and 6.0 ‰, respectively. In the tributary South Tiao, the δ 15N and δ 18O-NO3 values were as high as 9.5 and 7.0 ‰, while in the tributaries Mid Tiao and North Tiao, NO3-N in most of the samples had relatively low δ 15N and δ 18O-NO3 values from 2.3 to 7.5 ‰ and 4.7 to 7.0 ‰, separately. Our results also suggest that the dual isotope approach can help us develop the best management practice for relieving NO3-N pollution in the rivers at the tributary scale. 相似文献
993.
Per Angelstam Kjell Andersson Maths Isacson Dmitri V. Gavrilov Robert Axelsson Mattias Bäckström Erik Degerman Marine Elbakidze Elena Yu. Kazakova-Apkarimova Lotta Sartz Stefan Sädbom Johan Törnblom 《Ambio》2013,42(2):146-159
Barriers and bridges to implement policies about sustainable development and sustainability commonly depend on the past development of social–ecological systems. Production of metals required integration of use of ore, streams for energy, and wood for bioenergy and construction, as well as of multiple societal actors. Focusing on the Swedish Bergslagen region as a case study we (1) describe the phases of natural resource use triggered by metallurgy, (2) the location and spatial extent of 22 definitions of Bergslagen divided into four zones as a proxy of cumulative pressure on landscapes, and (3) analyze the consequences for natural capital and society. We found clear gradients in industrial activity, stream alteration, and amount of natural forest from the core to the periphery of Bergslagen. Additionally, the legacy of top-down governance is linked to today’s poorly diversified business sector and thus municipal vulnerability. Comparing the Bergslagen case study with other similar regions in Russia and Germany, we discuss the usefulness of multiple case studies. 相似文献
994.
Susan Taylor David B. Ringelberg Katerina Dontsova Charles P. Daghlian Marianne E. Walsh Michael R. Walsh 《Chemosphere》2013
Two compounds, 2,4-dinitroanisole (DNAN) and 3-nitro-1,2,4-triazol-5-one (NTO) are the main ingredients in a suite of explosive formulations that are being, or soon will be, fielded at military training ranges. We aim to understand the dissolution characteristics of DNAN and NTO and three insensitive muntions (IM) formulations that contain them. This information is needed to accurately predict the environmental fate of IM constituents, some of which may be toxic to people and the environment. We used Raman spectroscopy to identify the different constituents in the IM formulations and micro computed tomography to image their three-dimensional structure. These are the first three-dimensional images of detonated explosive particles. 相似文献
995.
Paulo Roger L. Alves Elke J.B.N. Cardoso Alexandre M. Martines José Paulo Sousa Amarildo Pasini 《Chemosphere》2013,90(11):2674-2682
Ecotoxicological laboratory tests (lower-tier tests) are fundamental tools for assessing the toxicity of pesticides to soil organisms. In this study, using these tests under tropical conditions, we quantified the impact of the insecticides imidacloprid, fipronil, and thiametoxam, and the fungicides captan and carboxin + thiram, all of which are used in the chemical treatment of crop seeds, on the survival, reproduction, and behavior of Eisenia andrei (Oligochaeta). With the exception of imidacloprid, none of the pesticides tested caused mortality in E. andrei in artificial soils. The LC50 of imidacloprid was estimated as 25.53 mg active ingredient kg?1 of dry soil. Earthworm reproduction rates were reduced by imidacloprid (EC50 = 4.07 mg kg?1), fipronil (EC20 = 23.16 mg kg?1), carboxin + thiram (EC50 = 56.38 mg kg?1), captan (EC50 = 334.84 mg kg?1), and thiametoxam (EC50 = 791.99 mg kg?1). Avoidance behavior was observed in the presence of imidacloprid (AC50 = 0.11 mg kg?1), captan (AC50 = 33.54 mg kg?1), carboxin + thiram (AC50 = 60.32 mg kg?1), and thiametoxam (AC50 = >20 mg kg?1). Earthworms showed a preference for soils with the insecticide fipronil. Imidacloprid was the most toxic of the substances tested for E. andrei. The avoidance test was the most sensitive test for most pesticides studied, but results varied between pesticides. These results offer new insights on the toxicity of pesticides used to treat seeds in tropical regions. However, they should be complemented with higher-tier tests in order to reduce the uncertainties in risk assessment. 相似文献
996.
N. Cheng K. V. Lo K. H. Yip 《Journal of environmental science and health. Part. B》2013,48(3):379-398
Abstract A laboratory scale two‐stage sequencing batch reactor (TSSBR) was used to study the effectiveness of pH as a real‐time control parameter in swine wastewater treatment. A Ringlace media was inserted into the A/O (Anoxic/Oxic) reactor for bacteria immobilization. The TSSBR was subjected to three levels of organic loading. The pH and ORP (Oxidation Reduction Potential) patterns obtained were consistent with distinct features, enabling the real‐time control strategy to effectively set a flexible aeration time pending on influent concentration, hence resulting in flexible cycle time and HRT (Hydraulic Retention Time) for the system. The real‐time process ensured a removal efficiency of over 99% and 95%, respectively, for ammonia and TOC (Total Organic Carbon). For NO3 ‐‐N and PO4 ‐3, the run with influent TOC = 4,000 mg/L yielded the most efficient removal of 61% and 95%, respectively. Test results suggest that pH can be a viable tool for on‐line real‐time control of a biological treatment process. 相似文献
997.
998.
Previous attempts to measure heavy metals in air are discussed with particular reference to lead. A polarographic method was developed for lead in air samples taken on glass fiber sheet. Using this method, the distribution of lead across the glass fiber sheet was investigated, and within experimental error, found to be uniform. Air samples from 18 Ontario cities, previously analyzed for benzo [a]pyrene content were analyzed. 相似文献
999.
J. B. Koogler R. S. Sholtes A. L. Danis C. I. Harding 《Journal of the Air & Waste Management Association (1995)》2013,63(4):211-214
In conjunction with a 15-month air quality survey of Jacksonville, Fia., a mathematical model has been developed to describe the dispersion of atmospheric pollutants. The source inventory used with the model was compiled, in part, from the data obtained from the sampling of all major sources within the area. The major sources were considered separately from the one-mile square area sources which accounted for the remainder of the emissions. Meteorological data was recorded continuously in the city including vertical temperature observations to 750 ft. The model was compiled in FORTRAN and can be used for both gaseous and particulate pollutants, by utilizing proper decay rates. The variant nature of meteorological parameters and emission rates are considered. The ground level concentrations of several pollutants which were determined for 24 hr periods at 11 sites and continuously at two other sites were used to check the model. A limited tracer study was carried out in conjunction with the project. 相似文献
1000.