全文获取类型
收费全文 | 3684篇 |
免费 | 37篇 |
国内免费 | 52篇 |
专业分类
安全科学 | 124篇 |
废物处理 | 193篇 |
环保管理 | 416篇 |
综合类 | 689篇 |
基础理论 | 662篇 |
环境理论 | 1篇 |
污染及防治 | 1140篇 |
评价与监测 | 282篇 |
社会与环境 | 241篇 |
灾害及防治 | 25篇 |
出版年
2023年 | 47篇 |
2022年 | 84篇 |
2021年 | 106篇 |
2020年 | 58篇 |
2019年 | 56篇 |
2018年 | 128篇 |
2017年 | 129篇 |
2016年 | 159篇 |
2015年 | 132篇 |
2014年 | 170篇 |
2013年 | 270篇 |
2012年 | 211篇 |
2011年 | 252篇 |
2010年 | 196篇 |
2009年 | 181篇 |
2008年 | 208篇 |
2007年 | 195篇 |
2006年 | 186篇 |
2005年 | 142篇 |
2004年 | 143篇 |
2003年 | 83篇 |
2002年 | 94篇 |
2001年 | 80篇 |
2000年 | 36篇 |
1999年 | 28篇 |
1998年 | 24篇 |
1997年 | 29篇 |
1996年 | 24篇 |
1995年 | 36篇 |
1994年 | 23篇 |
1993年 | 8篇 |
1992年 | 16篇 |
1991年 | 28篇 |
1990年 | 15篇 |
1989年 | 19篇 |
1988年 | 12篇 |
1987年 | 6篇 |
1986年 | 5篇 |
1985年 | 8篇 |
1984年 | 7篇 |
1982年 | 10篇 |
1981年 | 11篇 |
1979年 | 11篇 |
1970年 | 6篇 |
1966年 | 5篇 |
1962年 | 5篇 |
1961年 | 4篇 |
1960年 | 6篇 |
1959年 | 5篇 |
1953年 | 4篇 |
排序方式: 共有3773条查询结果,搜索用时 125 毫秒
41.
42.
43.
44.
45.
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
46.
Alberto Padilla Antonio Pulido-Bosch Maria L. Calvache Angela Vallejos 《Journal of the American Water Resources Association》1996,32(5):917-928
ABSTRACT: Autoregressive moving average (ABMA) models have been applied to study the flow series of the karstic springs of La Villa, Fuente Mayor (Spain), and Aliou (France). The theoretical meaning of the parameters involved in the model upon applying it to a simplified scheme of the emptying of a karstic aquifer is first analyzed. The types of transformations necessary to apply these models to the flow series that lack normality and have strong periodic components are also indicated, as are the advantages of this type of model and the physical significance of the parameters obtained, with respect to the standpoint of hydraulics, ranging from rather homogeneous aquifers (La Villa) to extremely karstic (Aliou), including aquifers with intermediate characteristics (Fuente Mayor). 相似文献
47.
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
48.
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
49.
Maria Konarska Agnieszka Wolska Maria Widerszal-Bazyl Joanna Bugajska Danuta Roman-Liu Arne Aar?s 《International journal of occupational safety and ergonomics》2005,11(1):65-76
A group of routine data entry operators (female) was included in the Polish MEPS (musculoskeletal--eyestrain--psychosocial--stress) study. Before the intervention, ergonomic assessment revealed improper working conditions such as inadequate lighting, uncomfortable chairs, and lack of forearm and wrist support while medical examination revealed that trapezius muscle load along with upper arm, head and back angles were higher than advisable. Subjects complained about neck and shoulder pain, visual problems, and psychosocial conditions. The ergonomic intervention included installation of new luminaires and Venetian blinds, new chairs, repair of ventilators, and optometric corrections. The results after the intervention showed mainly improvement in chair comfort, lighting conditions, visual strain, and sitting posture. However, financial limitations did not allow satisfactory completion of the intervention leading to a mixed interpretation of the results. 相似文献
50.
Gunnar Horgen Arne Aar?s Marvin J Dainoff Maria Konarska Magne Thoresen Barbara G F Cohen 《International journal of occupational safety and ergonomics》2005,11(1):77-92
Three groups of data entry female visual display terminal (VDT) workers from Norway (n = 30), Poland (n = 33) and the USA (n = 29) were compared. Before intervention, the Norwegian group reported more neck pain compared with the Polish group. The Polish group reported less shoulder pain than both the U.S. and the Norwegian groups. The clinical examination documented fewer symptoms and signs of musculoskeletal illness among the Polish participants compared with the Norwegian and the U.S. groups. After intervention, the Norwegian group reported a reduction in neck pain while the U.S. group reported a reduction in shoulder pain. The Polish group reported an increase in neck, shoulder and forearm pain at follow-up compared to after intervention. The Polish group recorded higher flexion of the upper arm at follow-up parallel with an increase of pain in the upper part of the body. Visual discomfort showed variable results in the 3 countries. 相似文献