全文获取类型
收费全文 | 17636篇 |
免费 | 1887篇 |
国内免费 | 7280篇 |
专业分类
安全科学 | 2096篇 |
废物处理 | 441篇 |
环保管理 | 2514篇 |
综合类 | 14549篇 |
基础理论 | 2822篇 |
环境理论 | 8篇 |
污染及防治 | 1971篇 |
评价与监测 | 1434篇 |
社会与环境 | 705篇 |
灾害及防治 | 263篇 |
出版年
2024年 | 98篇 |
2023年 | 556篇 |
2022年 | 806篇 |
2021年 | 933篇 |
2020年 | 970篇 |
2019年 | 915篇 |
2018年 | 741篇 |
2017年 | 806篇 |
2016年 | 877篇 |
2015年 | 1039篇 |
2014年 | 978篇 |
2013年 | 1567篇 |
2012年 | 1536篇 |
2011年 | 1686篇 |
2010年 | 1206篇 |
2009年 | 1331篇 |
2008年 | 1094篇 |
2007年 | 1380篇 |
2006年 | 1369篇 |
2005年 | 998篇 |
2004年 | 872篇 |
2003年 | 834篇 |
2002年 | 663篇 |
2001年 | 600篇 |
2000年 | 553篇 |
1999年 | 414篇 |
1998年 | 314篇 |
1997年 | 289篇 |
1996年 | 245篇 |
1995年 | 209篇 |
1994年 | 173篇 |
1993年 | 146篇 |
1992年 | 114篇 |
1991年 | 75篇 |
1990年 | 58篇 |
1989年 | 36篇 |
1988年 | 27篇 |
1987年 | 33篇 |
1986年 | 24篇 |
1985年 | 15篇 |
1984年 | 13篇 |
1983年 | 13篇 |
1982年 | 28篇 |
1981年 | 26篇 |
1980年 | 18篇 |
1979年 | 13篇 |
1978年 | 20篇 |
1973年 | 13篇 |
1972年 | 13篇 |
1971年 | 42篇 |
排序方式: 共有10000条查询结果,搜索用时 140 毫秒
561.
环境医学:人类生存发展战略的大课题 总被引:1,自引:0,他引:1
文章用大量翔实数据,分析论证:人类由于淡化环境意识,坚持急功近利的片面发展观,造成整个地球环境质量正在全面下降和恶化,全球已有1/5的人口受到环境污染之害的基点上,作者提出了只有跳出以自我生存为中心的狭隘圈,确立发展环境医学为主体的预防医学战略,并提示要遵循中国古代强调的“天人合一”论概念和钱学森提出的“开放的巨系统方法论”在当代科技领域进行“天地生人巨系统的综合集成研究”,树立“天地与我并生,万物与我同运”的自然生态观,为创建“生物心理社会自然”为模式的全科新医学,这是实现21世纪“人类健康工程”的开拓性目标。 相似文献
562.
本文通过对岷江干流(成都段)地表水和地下水的综合研究,分别提出了地表水污染防治对策和地下水水质防护措施,划分出了地表水防治不同时期的目标以及地下水开采管理目标。 相似文献
563.
污染物对水环境的影响主要发生在枯水期,此时水流状态处于稳态.Streeter-phelps(S-P)方程能预测简单稳态条件下的水质状况,并具有较高的计算织亏的精度. 相似文献
564.
根据扁矩形消声通道二维消声理论替代一维理论导出的消声系数Φ(α),研究了障板消声结构的Φ(α)计算机程序和消声量与障板几何尺寸的关系 相似文献
565.
566.
Fed-batch cultures of recombinantEscherichia coli strains were carried out for the production of poly(3-hydroxybutyric acid) (PHB) in a chemically defined medium. TheE. coli strains used were XL1-Blue, harboring pSYL105, a stable high-copy number plasmid containing theAlcaligenes eutrophus polyhydroxyalkanoate (PHA) genes, and XL1-Blue, harboring pSYL107, which is pSYL105 containing theE. coli ftsZ gene to suppress filamentation. With XL1-Blue(pSYL105) the final cell mass and PHB concentration obtained in 62 h were 102 and 22.5 g/L, respectively. Fed-batch culture of XL1-Blue(pSYL107) under identical conditions resulted in a final cell mass and PHB concentration of 127.5 and 48.2 g/L, respectively. The PHB contents obtained with XL1-Blue(pSYL105) and XL1-Blue(pSYL107) were 22.1 and 37.8%, respectively. Therefore, PHB was more efficiently produced in a defined medium by employing filamentation-suppressed recombinantE. coli. 相似文献
567.
Arnold Gurtner-Zimmermann 《Environmental management》1996,20(4):449-459
This article presents a model of remedial action planning, which includes four key variables that determine progress in plan development and implementation and explain the differing level of achievement in individual sites. The model is illustrated by the characteristics and developments of four remedial action plan (RAP) processes (Lower Green Bay and Fox River, Collingwood Harbour, Spanish Harbour, and the Metro Toronto and Region RAPs). Differences in the local context of the plans have, to a significant degree, predisposed individual planning and implementation experiences. Local context includes three variables, namely geographical—technical and sociopolitical aspects and the previous history of water pollution management in the area. RAP precursors are a necessary precondition for progress in planning and substantive achievements. While there is a tendency that most geographically focused RAPs in administratively simple areas accomplish most, the motivation and political clout of RAP participants are strongly intervening factors. Resource input from upper levels of government, in particular financial commitment for plan implementation, is the fourth necessary ingredient for progress due to the RAPs' weak regulatory and institutional framework. Unfortunately, upper levels of government have shown widespread reluctance to lead in remedial action planning. This was only in part offset by local commitment and support for RAP and its cause. 相似文献
568.
569.
570.
D. E. Barb J. F. Cruise X. Mo 《Journal of the American Water Resources Association》1996,32(3):511-519
ABSTRACT: A model for urban stormwater quality was developed in this study. The basis for the model is the process by which pollutants build up on the watershed surface. For the wet climate of the study site, it was assumed that there exists an interval of time over which the pollutant buildup equals the pollutant washoff (no accumulation of pollutant). The buildup model was represented by a linear function of the antecedent dry time. The buildup function was then linked with a pollutant washoff model represented by a power function of the storm runoff volume. Various time intervals for no net accumulation were tested to calibrate the model. The model was calibrated to observed data for two small urban basins in Baton Rouge, Louisiana, and model results were used to analyze the behavior of phosphorus concentrations in storm runoff from these basins over a long period of time. 相似文献