全文获取类型
收费全文 | 39710篇 |
免费 | 436篇 |
国内免费 | 704篇 |
专业分类
安全科学 | 1143篇 |
废物处理 | 1849篇 |
环保管理 | 4735篇 |
综合类 | 6647篇 |
基础理论 | 10177篇 |
环境理论 | 21篇 |
污染及防治 | 10303篇 |
评价与监测 | 2789篇 |
社会与环境 | 2947篇 |
灾害及防治 | 239篇 |
出版年
2023年 | 202篇 |
2022年 | 452篇 |
2021年 | 429篇 |
2020年 | 307篇 |
2019年 | 377篇 |
2018年 | 640篇 |
2017年 | 669篇 |
2016年 | 986篇 |
2015年 | 736篇 |
2014年 | 1172篇 |
2013年 | 3229篇 |
2012年 | 1379篇 |
2011年 | 1849篇 |
2010年 | 1495篇 |
2009年 | 1568篇 |
2008年 | 1871篇 |
2007年 | 1923篇 |
2006年 | 1640篇 |
2005年 | 1432篇 |
2004年 | 1326篇 |
2003年 | 1389篇 |
2002年 | 1237篇 |
2001年 | 1577篇 |
2000年 | 1116篇 |
1999年 | 647篇 |
1998年 | 444篇 |
1997年 | 459篇 |
1996年 | 462篇 |
1995年 | 561篇 |
1994年 | 542篇 |
1993年 | 443篇 |
1992年 | 463篇 |
1991年 | 451篇 |
1990年 | 496篇 |
1989年 | 420篇 |
1988年 | 366篇 |
1987年 | 355篇 |
1986年 | 295篇 |
1985年 | 329篇 |
1984年 | 351篇 |
1983年 | 329篇 |
1982年 | 313篇 |
1981年 | 297篇 |
1980年 | 240篇 |
1979年 | 271篇 |
1978年 | 224篇 |
1977年 | 171篇 |
1975年 | 184篇 |
1974年 | 170篇 |
1972年 | 194篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
981.
Waste materials for activated carbon preparation and its use in aqueous-phase treatment: a review 总被引:6,自引:0,他引:6
Dias JM Alvim-Ferraz MC Almeida MF Rivera-Utrilla J Sánchez-Polo M 《Journal of environmental management》2007,85(4):833-846
Commercial activated carbon is a preferred adsorbent for the removal of micropollutants from the aqueous phase; however, its widespread use is restricted due to high associated costs. To decrease treatment costs, attempts have been made to find inexpensive alternative activated carbon (AC) precursors, such as waste materials. Some reviews report the use of waste materials for the preparation of AC; however, these studies are restricted to either type of wastes, preparation procedures, or specific aqueous-phase applications. The present work reviews and evaluates literature dedicated both to the preparation of AC by recycling different types of waste materials and also to its application in various aqueous-phase treatments. It is clear that conventional (from agriculture and wood industry) and non-conventional (from municipal and industrial activities) wastes can be used to prepare AC, that can be applied in various aqueous treatment processes, namely to remove organic pollutants, dyes, volatile organic compounds, and heavy metals. Moreover, high surface areas can be obtained using either physical or chemical activation; however, combined treatments might enhance the surface properties of the adsorbent, therefore increasing its adsorption capacity. It is evident from the revision made that AC prepared from both conventional and non-conventional wastes might effectively compete with the commercial ones. This happens mostly when the activation procedures are optimized considering both the raw material used to produce the carbons and the contaminants to be removed. 相似文献
982.
Field-scale relationships between soil test phosphorus (STP) and flow-weighted mean concentrations (FWMCs) of dissolved reactive phosphorus (DRP) and total phosphorus (TP) in runoff are essential for modeling phosphorus losses, but are lacking. The objectives of this study were (i) to determine the relationships between soil phosphorus (STP and degree of phosphorus saturation (DPS)) and runoff phosphorus (TP and DRP) from field-sized catchments under spring snowmelt and summer rainfall conditions, and (ii) to determine whether a variety of depths and spatial representations of STP improved the prediction of phosphorus losses. Runoff was monitored from eight field-scale microwatersheds (2 to 248 ha) for 3 yr. Soil test phosphorus was determined for three layers (0 to 2.5 cm, 0 to 5 cm, and 0 to 15 cm) in spring and fall and the DPS was determined for the surface layer. Average STP (0 to 15 cm) ranged from 3 to 512 mg kg(-1), and DPS (0 to 2.5 cm) ranged from 5 to 91%. Seasonal FWMCs ranged from 0.01 to 7.4 mg L(-1) DRP and from 0.1 to 8.0 mg L(-1) TP. Strong linear relationships (r2=0.87 to 0.89) were found between the site mean STP and the FWMCs of DRP and TP. The relationships had similar extraction coefficients, intercepts, and predictive power among all three soil layers. Extraction coefficients (0.013 to 0.014) were similar to those reported for other Alberta studies, but were greater than those reported for rainfall simulation studies. The curvilinear DPS relationship showed similar predictive ability to STP. The field-scale STP relationships derived from natural conditions in this study should provide the basis for modeling phosphorus in Alberta. 相似文献
983.
L. M. Cox W. J. Rawls J. F. Zuzel 《Journal of the American Water Resources Association》1975,11(5):1009-1012
ABSTRACT: Snow, one of Nature's greatest reservoirs, supplies most of the usable water in the Western United States. Reliable predictions of the quantity and timing of the release of this water are used in making management decisions involving irrigation, stock water and municipal water supplies, hydro-power generation, recreation, navigation, and pollution control Practically oriented research is vital for the proper development and management of this resource. In southwestern Idaho, the Northwest Watershed Research Center, ARS, USDA, is conducting intensive investigations for assessing snow Volumes, snow water content, and snow-melt over a watershed. Application of these research findings will result in better development and management of the water stored as snow in Nature's reservoir. 相似文献
984.
985.
986.
987.
988.
P. A. Zadubrovskiy I. V. Zadubrovskaya M. A. Potapov O. F. Potapova V. I. Evsikov 《Russian Journal of Ecology》2016,47(1):82-87
Demographic structure and its seasonal dynamics have been studied in colonies of narrow-skulled voles (Lasiopodomys gregalis Pall.) in Northern Kulunda. Three types of colonies have been distinguished: (I) true colonies (large, complex families), (II) simple families (nuclear or incomplete), and (III) all-male colonies. Changes in their sex, age, and functional composition (based on animal migration activity) during the breeding season have been analyzed. 相似文献
989.
E.?M.?NkoanaEmail author T.?Waas A.?Verbruggen C.?J.?Burman J.?Hugé 《Environment, Development and Sustainability》2017,19(5):1731-1760
The assumptions and empirical evidence linking climate change adaptation to development cooperation have led to the emergence of a range of climate change adaptation tools aiming at improving the quality of development cooperation initiatives in times of global change. In order to assess the quality of these tools, we develop an analytic framework to critically assess the social learning and sustainable development outcomes of climate change adaptation tools. The analytic framework defines project objectives, participation typology, participation tools, participation stages, scenarios development, modelling exercises, stakeholder analysis and risk communication strategies that support quality participation outcomes. 相似文献
990.
A pilot survey of blood lead levels in various types of workers in the United Arab Emirates. 总被引:1,自引:0,他引:1
The aim of the present study is to determine the effect of blood lead on the health of industrial workers in United Arab Emirates (UAE). This is a cross-sectional pilot survey of blood lead levels (BLL) of 100 industrial workers (exposed) and 100 non-industrial workers (nonexposed), matched for age, sex and nationality selected from Al-Ain, Abu-Dhabi Emirate. Industrial workers had significantly higher mean of BLL (77.5+/-42.8 microg/dl and median 80.9 microg/dl) than non-industrial workers (19.8+/-12.3 microg/dl and median 11.0 microg/dl). In the present study, reported symptoms among industrial workers were strongly associated with BLL nausea/vomiting, muscular symptoms, dizziness, fatigue, irritability, memory disturbances, insomnia and allergic conjuctivitis, rhinitis and dermatitis. Furthermore, the present study revealed that industrial workers had higher prevalence of respiratory symptoms for phlegm, shortness of breath and diagnosed asthma. In conclusion, this study determined that occurrence of certain symptoms might be associated with lead exposure among industrial workers. 相似文献