全文获取类型
收费全文 | 2541篇 |
免费 | 25篇 |
国内免费 | 24篇 |
专业分类
安全科学 | 81篇 |
废物处理 | 89篇 |
环保管理 | 321篇 |
综合类 | 534篇 |
基础理论 | 524篇 |
环境理论 | 2篇 |
污染及防治 | 734篇 |
评价与监测 | 145篇 |
社会与环境 | 144篇 |
灾害及防治 | 16篇 |
出版年
2023年 | 23篇 |
2022年 | 31篇 |
2021年 | 45篇 |
2020年 | 30篇 |
2019年 | 33篇 |
2018年 | 67篇 |
2017年 | 73篇 |
2016年 | 91篇 |
2015年 | 87篇 |
2014年 | 100篇 |
2013年 | 134篇 |
2012年 | 107篇 |
2011年 | 164篇 |
2010年 | 137篇 |
2009年 | 148篇 |
2008年 | 142篇 |
2007年 | 139篇 |
2006年 | 109篇 |
2005年 | 76篇 |
2004年 | 105篇 |
2003年 | 72篇 |
2002年 | 88篇 |
2001年 | 75篇 |
2000年 | 44篇 |
1999年 | 25篇 |
1998年 | 24篇 |
1997年 | 32篇 |
1996年 | 25篇 |
1995年 | 39篇 |
1994年 | 30篇 |
1993年 | 11篇 |
1992年 | 23篇 |
1991年 | 30篇 |
1990年 | 14篇 |
1989年 | 19篇 |
1988年 | 8篇 |
1985年 | 9篇 |
1984年 | 12篇 |
1983年 | 6篇 |
1982年 | 16篇 |
1981年 | 10篇 |
1979年 | 11篇 |
1970年 | 10篇 |
1968年 | 5篇 |
1967年 | 5篇 |
1966年 | 5篇 |
1965年 | 8篇 |
1964年 | 5篇 |
1960年 | 6篇 |
1956年 | 5篇 |
排序方式: 共有2590条查询结果,搜索用时 375 毫秒
41.
42.
43.
44.
45.
46.
47.
ZHANG Shao-yuan Renze van Houten Dick H. Eikelboom JIANG Zhao-chun FAN Yao-bo WANG Ju-si 《环境科学学报(英文版)》2002,14(4):501-507
Based on the microorganism kinetic model, the formula for computing hydraulic retention time in a membrane bioreactor system (MBR) is derived. With considering HRT as an evaluation index a combinational approach was used to discuss factors which have an effect on MBR. As a result, the influencing factors were listed in order from strength to weakness as: maximum specific removal rate K, saturation constant Ks, maintenance coefficient m, maximum specific growth rate ,ua and observed yield coefficient Yobs. Moreover, the formula was simplified, whose parameters were experimentally determined in petrochemical wastewater treatment. The simplified formula is θ= 1.1( 1/β -1)(Ks S)/KXo , for oetroehemical wastewater treatment K and Ko eaualed 0.185 and 154.2, resoectively. 相似文献
48.
In 1992 a comprehensive health-promotion project was initiated in seven nursing-homes in the Netherlands. This project was designed to implement an ergonomic-educational programme, with the intention of reducing physical workload and to bring about safe working in order to prevent work-related musculoskeletal complaints. After a period of external support, employees of the nursing-homes should be able to proceed with the programme independently. In this paper the content of the programme and its underlying strategies and theories are described. So far, the programme has got off to a good start in all the nursing-homes. Positive effects of the programme could be demonstrated and guidelines and protocols for safe working were introduced. However, it is as yet too early for definitive conclusions to be drawn regarding the aspect of continuity. 相似文献
49.
L. J. Sheppard A. Crossley I. D. Leith K. J. Hargreaves J. A. Carfrae N. van Dijk J. N. Cape D. Sleep D. Fowler J. A. Raven 《Water, Air, & Soil Pollution: Focus》2005,4(6):197-205
Critical N loads for ombrotrophic bogs, which often contain rare and N-sensitive plants (especially those in lower plant groups: lichens, mosses and liverworts), are based on very few experimental data from measured, low background N deposition areas. Additionally the relative effects of reduced versus oxidised N are largely unknown. This paper describes an automated field exposure system (30 km S. of Edinburgh, Scotland) for treating ombrotrophic bog vegetation with fine droplets of oxidised N (NaNO3) and reduced N (NH4Cl). Whim Moss exists in an area of low ambient N deposition (ca. 8 kg N ha?1 y?1), the sources and quantification of which are described. The wet N treatment system is run continuously, and is controlled/activated by wind speed and rainfall to provide a unique simulation of “real worl” treatment patterns (no rain=no treatment). Simulated precipitation is supplied at ionic concentrations below 4 mM in rainwater collected on site. Treatments provide a replicated dose response to 16, 32 and 64 kg N ha?1 y?1 adjusted for ambient deposition (8 kg N ha?1 y?1). The 16 and 64 kg N ha?1 y?1 are duplicated with a P+K supplement. Baseline soil chemistry and foliar nutrient status was established for all 44 plots for Calluna vulgaris, Sphagnum capillifolium, Hypnum jutlandicum and Cladonia portentosa. 相似文献
50.
Marinka D de Groot Tim Bosch Sandra M Eikhout Peter Vink 《International journal of occupational safety and ergonomics》2005,11(3):331-337
A variety of seals is used to close bags. Each seal has advantages and disadvantages. For shop assistants sealing bags could be a repetitive physically demanding action. Opening and closing the bags again can cause some discomfort or annoyance for consumers. Besides, it is an activity which can endanger safety, i.e., knives being used in opening, children swallowing the systems of sealing. To prevent these problems a new sealing system was developed. In this paper the opinion of shop assistants, consumers and experts on several bag sealing systems was studied. It appeared that for sealing plastic bags, adhesive tape with paper is the best out of 4 systems, closely followed by adhesive tape. It is discussed that for the elderly, there is still room for improvement in opening bag seals. 相似文献