全文获取类型
收费全文 | 19338篇 |
免费 | 141篇 |
国内免费 | 177篇 |
专业分类
安全科学 | 458篇 |
废物处理 | 835篇 |
环保管理 | 1914篇 |
综合类 | 4041篇 |
基础理论 | 4565篇 |
环境理论 | 11篇 |
污染及防治 | 5221篇 |
评价与监测 | 1496篇 |
社会与环境 | 1030篇 |
灾害及防治 | 85篇 |
出版年
2023年 | 110篇 |
2022年 | 256篇 |
2021年 | 251篇 |
2020年 | 148篇 |
2019年 | 176篇 |
2018年 | 373篇 |
2017年 | 400篇 |
2016年 | 557篇 |
2015年 | 402篇 |
2014年 | 663篇 |
2013年 | 1415篇 |
2012年 | 740篇 |
2011年 | 912篇 |
2010年 | 687篇 |
2009年 | 706篇 |
2008年 | 872篇 |
2007年 | 856篇 |
2006年 | 769篇 |
2005年 | 679篇 |
2004年 | 617篇 |
2003年 | 595篇 |
2002年 | 547篇 |
2001年 | 667篇 |
2000年 | 408篇 |
1999年 | 305篇 |
1998年 | 169篇 |
1997年 | 184篇 |
1996年 | 191篇 |
1995年 | 218篇 |
1994年 | 207篇 |
1993年 | 141篇 |
1992年 | 183篇 |
1991年 | 193篇 |
1990年 | 186篇 |
1989年 | 154篇 |
1988年 | 170篇 |
1987年 | 104篇 |
1986年 | 151篇 |
1985年 | 139篇 |
1984年 | 134篇 |
1983年 | 125篇 |
1982年 | 138篇 |
1981年 | 130篇 |
1980年 | 99篇 |
1979年 | 107篇 |
1978年 | 108篇 |
1974年 | 107篇 |
1967年 | 102篇 |
1966年 | 98篇 |
1964年 | 98篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
201.
N. Mithil Kumar K. Varaprasad G. Ramachandra Reddy G. Siva Mohan Reddy Y. Sivabharathi G. Venkata Subba Reddy S. Venkata Naidu 《Journal of Polymers and the Environment》2011,19(1):225-229
Synthesis and characterization of novel biodegradable, water soluble and optically active DL-malic acid (DMA) and citric acid
(CA) copolymers were studied for possible use as antibacterial agents. The copolymers were synthesized by direct bulk melt
condensation in the absence of a catalyst above 150 °C. Characterization of obtained copolymers was carried out with the help
of infrared absorption spectra, differential scanning calorimetry and thermo gravimetric analysis. The antibacterial activity
of copolymers against bacteria was investigated. The results obtained shows the above copolymers possess a broad wound dressing
activity against different types of bacteria and may be useful as antibacterial agents. 相似文献
202.
Silvestre García de Jalón Ana Iglesias Ruth Cunningham Juan I. Pérez Díaz 《Regional Environmental Change》2014,14(3):1229-1242
Agricultural water management needs to evolve in view of increased water scarcity, especially when farming and natural protected areas are closely linked. In the study site of Doñana (southern Spain), water is shared by rice producers and a world heritage biodiversity ecosystem. Our aim is to contribute to defining adaptation strategies that may build resilience to increasing water scarcity and minimize water conflicts among agricultural and natural systems. The analytical framework links a participatory process with quantitative methods to prioritize the adaptation options. Bottom-up proposed adaptation measures are evaluated by a multi-criteria analysis (MCA) that includes both socioeconomic criteria and criteria of the ecosystem services affected by the adaptation options. Criteria weights are estimated by three different methods—analytic hierarchy process, Likert scale and equal weights—that are then compared. Finally, scores from an MCA are input into an optimization model used to determine the optimal land-use distribution in order to maximize utility and land-use diversification according to different scenarios of funds and water availability. While our results show a spectrum of perceptions of priorities among stakeholders, there is one overriding theme that is to define a way to restore part of the rice fields to natural wetlands. These results hold true under the current climate scenario and even more so under an increased water scarcity scenario. 相似文献
203.
204.
205.
Alves Andreia Cristina Fonseca Antero Romario Victor Pacheco de Oliveira Sergio Botelho Ojala Satu Anneli Scalize Paulo Sérgio 《Environmental science and pollution research international》2019,26(24):24850-24862
Environmental Science and Pollution Research - Bisphenol-A is widely used chemical in industry and unfortunately often detected in natural waters. Considered as an emerging pollutant, bisphenol-A... 相似文献
206.
207.
Cellulose decomposition in soils amended over twenty year ago with heavy metal-contaminated sewage sludges was assessed by using the cotton-strip assay. The soils of the Luddington Experiment now contain concentrations of Cu, Ni and Zn in selected plots that approximate to or exceed the statutory limits for these elements in sewage sludge-amended soils. The rates of cellulose decomposition were generally lower in the plots with elevated metal concentrations, relative to uncontaminated sludge-amended and unsludged controls. Generally, the metal-rich plots showed reductions in the time taken to reach 50% cotton-tensile-strength loss (CTSL). However, the reductions could not be consistently related to any one metal. The difference in decomposition rates between treatments was systematically reduced over the duration of a time-course experiment. A lower initial population of the appropriate decomposer community of micro-organisms may account for the observed short-term lag in decomposition rates. 相似文献
208.
209.
The potential of Corbicula fluminea (Müller) as an indicator for trace metal pollution was investigated. Laboratory experiments show that Corbicula has the capability to accumulate and eliminate trace metals in relation to their concentrations in ambient water. However, an effect of individual size was observed. Seasonal variations in the concentrations of Cd, Co, Cu, Fe, Mn, Ni, Pb, V and Zn in Corbicula, water and particulate matter from the upper section of the Shatt al-Arab River were studied. Sediment samples were also analysed. Metal concentrations were determined by means of flameless AAS. It was found that Corbicula is a suitable bio-indicator for monitoring of trace metal pollution. Metal concentrations in Corbicula tissues correlated better with their corresponding concentrations in particulate matter than with the dissolved form. Temporal variations in metal concentrations were attributed to several factors, including fluctuations in metal inputs, and in geochemical and hydrological characteristics of the water. The obtained levels of trace metals were comparable to those reported for control sites, with the exception of Cd, Cu and Zn whose concentrations were higher in both Corbicula and particulate matter. 相似文献
210.
The root growth response to air pollution in populations of Anagallis arvensis growing about 0.5, 2, 6, 12 and 20 km leeward from a power plant complex varied with the level of pollution, age of the stand and meteorological conditions. The roots were more affected by the pollutants at a young stage and the loss in net primary productivity was proportional to the pollution level. The populations up to 2 km from the source of pollution completed their life cycle quickly. The coal consumption rate at the power plant, relative humidity, wind direction and other environmental factors were found to influence the degree of growth response to air pollution. 相似文献