全文获取类型
收费全文 | 39539篇 |
免费 | 330篇 |
国内免费 | 224篇 |
专业分类
安全科学 | 865篇 |
废物处理 | 1837篇 |
环保管理 | 5190篇 |
综合类 | 5998篇 |
基础理论 | 11485篇 |
环境理论 | 27篇 |
污染及防治 | 9655篇 |
评价与监测 | 2740篇 |
社会与环境 | 2103篇 |
灾害及防治 | 193篇 |
出版年
2022年 | 187篇 |
2021年 | 194篇 |
2019年 | 224篇 |
2018年 | 1780篇 |
2017年 | 1656篇 |
2016年 | 1674篇 |
2015年 | 630篇 |
2014年 | 728篇 |
2013年 | 2219篇 |
2012年 | 1292篇 |
2011年 | 2487篇 |
2010年 | 1687篇 |
2009年 | 1583篇 |
2008年 | 2077篇 |
2007年 | 2471篇 |
2006年 | 1242篇 |
2005年 | 1065篇 |
2004年 | 1063篇 |
2003年 | 1027篇 |
2002年 | 1053篇 |
2001年 | 1289篇 |
2000年 | 896篇 |
1999年 | 569篇 |
1998年 | 446篇 |
1997年 | 444篇 |
1996年 | 453篇 |
1995年 | 491篇 |
1994年 | 455篇 |
1993年 | 405篇 |
1992年 | 418篇 |
1991年 | 381篇 |
1990年 | 383篇 |
1989年 | 418篇 |
1988年 | 352篇 |
1987年 | 301篇 |
1986年 | 282篇 |
1985年 | 311篇 |
1984年 | 310篇 |
1983年 | 333篇 |
1982年 | 333篇 |
1981年 | 284篇 |
1980年 | 249篇 |
1979年 | 275篇 |
1978年 | 235篇 |
1977年 | 201篇 |
1976年 | 210篇 |
1975年 | 200篇 |
1974年 | 180篇 |
1973年 | 178篇 |
1972年 | 206篇 |
排序方式: 共有10000条查询结果,搜索用时 8 毫秒
181.
J A Heidman 《Journal - Water Pollution Control Federation》1975,47(6):1493-1498
182.
183.
184.
In the UK for the period 1994-99, a broad range of environmental projects were given financial support through the European Agriculture Guidance and Guarantee Fund under the Objective 1 and Objective 5b programmes. This paper is concerned with the ex-post evaluation of these projects set within a Sustainable Development framework. The aim was to identify project types or characteristics that offered the greatest return on investment. A classification of six broad project types was adopted. The evaluation revealed that there were significant differences between individual projects with respect to the type and scale, and temporal and social distribution of the benefits they delivered. In particular, as well as delivering environmental and economic benefits, many projects made a significant contribution to the development of human and social capital. The paper concludes that it is possible to improve the basis for future project selection in order to maximise the returns on environmental investments in the context of sustainable development. 相似文献
185.
This article does not focus on adaptation or mitigation policy directly but on an allied opportunity that exists for the Pacific
Islands via the auspices of the Climate Convention, because the existing very costly energy systems used in the Pacific Island
region are fossil-fuel dependent. It is argued here that efforts can be made towards the development of energy systems that
are ecologically sustainable because Pacific Island nations are eligible to receive assistance to introduce renewable energy
technology and pursue energy conservation via implementation mechanisms of the Climate Convention and, in particular, through
transfer of technology and via joint implementation.
It is contended that assistance in the form of finance, technology, and human resource development from developed countries
and international organizations would provide sustainable benefits in improving the local Pacific Island environments. It
is also emphasized that mitigation of greenhouse gas emissions is not the responsibility of the Pacific Islands as they contribute
very little on a per capita global scale and a tiny proportion of total global greenhouse gas emissions. 相似文献
186.
L. A. Kelly J. Stellwagen A. Bergheim 《Journal of the American Water Resources Association》1996,32(5):1017-1025
ABSTRACT: Recent studies suggest that waste generation from the freshwater phase of Atlantic salmon (Salmo salar L.) production varies considerably on an annual basis. A fish farm on the West Coast of Scotland was visited regularly during a two-year period to determine inflow and outflow water quality. Waste output budgets of suspended solids (SS), biochemical oxygen demand (BOD), total nitrogen (TN), total phosphorus (TP), total ammonia nitrogen (TAN = NH3+NH4+), dissolved reactive phosphorus (DRP) and total phosphorus (TP) were produced. The annual waste loadings obtained were 71 kg TN t fish?1 yr?1 (one year of data only), 10.9–11.1 kg TP t fish?1 yr?1, 1.2–2.1 kg DRP t fish?1 yr?1, 422–485 kg BOD5 t fish?1 yr?1, 327–337 kg SS t fish?1 yr?1, and 30–35 kg TAN-N t fish?1 yr?1. Simple linear regression models relating waste parameter production to water temperature and feeding regime were developed. When compared to existing data for other salmonid production systems, greater ranges of daily waste loadings were observed. Wide variations in concentrations of these parameters during a daily cycle were also observed, suggesting that mass balance estimates of waste production will provide more robust estimates of waste output than frequent monitoring of outflow water quality. 相似文献
187.
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
188.
189.
Elvis G. Ngwenya Maud Walsh Caroline A. Metosh‐Dickey Ralph J. Portier 《补救:环境净化治理成本、技术与工艺杂志》2006,16(2):79-90
Biological and physicochemical approaches were utilized in a treatment train for acid mine dis charge (AMD) waters. Anaerobic bioreactors, chemical precipitation reactors, and biopolymer chelation reactors, operated in static, semicontinuous, and continuous flow modes, removed significant quantities of metals and sulfates associated with AMD water. Static tests indicated accept able copper removal via precipitation by generation of hydrogen sulfide in anaerobic reactors. However, low pH affected the biopolymer coating in the chelation reactor, resulting in loss of bed surface. Corrections of AMD to pH > 7 resulted in some metal precipitationprior to biopolymer treatment. A series of static semicontinuous tests at pH 5.0 provided improved metal and sulfate removal. Copper (Cu+) was reduced to trace concentrations, while manganese (Mn+), although reduced, proved to be the most recalcitrant of the metals. © 2006 Wiley Periodicals, Inc. 相似文献
190.
Calculating overpressure from BLEVE explosions 总被引:3,自引:0,他引:3
E. Planas-Cuchi J. M. Salla J. Casal 《Journal of Loss Prevention in the Process Industries》2004,17(6):431-436
Although a certain number of authors have analyzed the prediction of boiling liquid expanding vapour explosion (BLEVE) and fireball effects, only very few of them have proposed methodologies for predicting the overpressure from such explosions. In this paper, the methods previously published are discussed and shown to introduce a significant overestimation due to the erroneous thermodynamic assumptions—ideal gas behaviour and isentropic vapour expansion—on which they are based (in fact, they give the maximum value of overpressure which can be caused by a BLEVE). A new approach is proposed, based on the—more realistic—assumption of an adiabatic and irreversible expansion process; the real properties of the substance involved in the explosion are used. The two methods are compared through the application to a given case. 相似文献