全文获取类型
收费全文 | 102333篇 |
免费 | 1730篇 |
国内免费 | 5618篇 |
专业分类
安全科学 | 4558篇 |
废物处理 | 4050篇 |
环保管理 | 14875篇 |
综合类 | 28125篇 |
基础理论 | 28159篇 |
环境理论 | 78篇 |
污染及防治 | 18815篇 |
评价与监测 | 5797篇 |
社会与环境 | 4095篇 |
灾害及防治 | 1129篇 |
出版年
2023年 | 612篇 |
2022年 | 1362篇 |
2021年 | 1291篇 |
2020年 | 1045篇 |
2019年 | 1198篇 |
2018年 | 1561篇 |
2017年 | 1700篇 |
2016年 | 2667篇 |
2015年 | 2490篇 |
2014年 | 3527篇 |
2013年 | 10498篇 |
2012年 | 3242篇 |
2011年 | 3735篇 |
2010年 | 4115篇 |
2009年 | 4259篇 |
2008年 | 2929篇 |
2007年 | 2615篇 |
2006年 | 2923篇 |
2005年 | 2704篇 |
2004年 | 2907篇 |
2003年 | 2786篇 |
2002年 | 2285篇 |
2001年 | 2510篇 |
2000年 | 2311篇 |
1999年 | 1897篇 |
1998年 | 1677篇 |
1997年 | 1658篇 |
1996年 | 1753篇 |
1995年 | 1831篇 |
1994年 | 1632篇 |
1993年 | 1471篇 |
1992年 | 1413篇 |
1991年 | 1365篇 |
1990年 | 1297篇 |
1989年 | 1242篇 |
1988年 | 1082篇 |
1987年 | 988篇 |
1986年 | 1007篇 |
1985年 | 1077篇 |
1984年 | 1169篇 |
1983年 | 1170篇 |
1982年 | 1183篇 |
1981年 | 1098篇 |
1980年 | 942篇 |
1979年 | 925篇 |
1978年 | 817篇 |
1977年 | 716篇 |
1976年 | 637篇 |
1973年 | 632篇 |
1972年 | 636篇 |
排序方式: 共有10000条查询结果,搜索用时 366 毫秒
751.
752.
福建省森林固定CO2价值评估 总被引:10,自引:0,他引:10
借鉴国内外研究成果,引入“市场逼近系数”,构造森林固定CO2效益经济结构模型,评估福建省森林固定CO2价值,为福建省森林资源的科学管理和资产评估提供了借鉴和参考。 相似文献
753.
壳体是机械中广泛使用的重要零件之一.采用冷挤压工艺可提高质量、降低成本.对不锈钢壳体成形工艺及模具设计作了详细讨论. 相似文献
754.
755.
Becker E. W. Bier W. Ehrfeld W. Schubert K. Schütte R. Seidel D. 《Die Naturwissenschaften》1976,63(9):407-411
The Science of Nature - The development of reliable manufacturing methods for commercial separation elements, the successful operation of separative stages, and extensive tests performed on plant... 相似文献
756.
J. Altenburger Th. Dielacher P. Eder H. Ferner M. Fegerl J. Fresner O. Gelinek A. Kogler J. Jantschgi M. Nussbaumer B. Russegger H. Schnitzer K. Schauer B. Sebesta J. Seiler F. Sprenger H. Widenmeyer 《Journal of Cleaner Production》1994,2(3-4)
The paper focuses upon the organization of a federal state-funded pollution prevention project in the Styrian industry. The project includes 13 companies from the textile, pulp and paper, machine building, wood working and printed circuit board manufacturing industries, covering most of the sectors and sizes in the Styrian industry. It started in January 1994 and will last for one year. It will demonstrate the possibilities of pollution prevention and the need for further research work. This project will make use of the methods and tools that were refined in the Austrian Prepare project. As a first step, a systematic balance of all the inputs and outputs of a company is made, after which the weak points and inefficiencies of material and energy use are identified and the options for improvements, both economical and ecological, are defined. Consequently, modifications in products and production lead to a situation with less waste and emissions. The preliminary lessons from these projects are presented: as a rule, the utilities (consumption of process materials and water, cleaning, energy, preparatory and finishing steps) are treated as black boxes and usually represent a considerable optimization potential. In these areas especially there is usually a lack of information and coordination as well as a need for a systematic and comprehensive approach. Leadership in the company and creative consultants are needed for starting lasting successful pollution prevention projects. 相似文献
757.
气相色谱法测定汽油作业环境中MTBE含量 总被引:1,自引:0,他引:1
建立了汽油作业场所空气中MTBE的气相色谱测定方法。空气中的MTBE用注射器采集,直接进样,经大口径毛细管柱分离,氢焰离子化检测器检测,以保留时间定性,峰面积定量,并考察了MTBE与甲醇、正己烷的分离效果。 相似文献
758.
759.
ZHANG Jian-ying QIU Li-min HE Jia LIAO Yuan LUO Yong-ming College of Environmental Resource Sciences Zhejiang University Hangzhou China. Soil Environment Bioremediation Research Center Institute of Soil Science Chinese Academy of Sciences Nanjing China 《环境科学学报(英文版)》2007,(3)
A total of 198 agricultural soil samples were collected from Zhangjiagang and Changshu in Southern Jiangsu for analysis of 13 polychlorinated biphenyls (PCBs) in order to assess the levels of pollution, sources, area distribution, and potential risk for the environment. All methods were rigorously tested and an adequate quality control was ensured. Only one site had no PCBs residues, and the highest total PCBs concentration in the surface soils was 32.83 ng/g. The average concentration in all the soil samples was 4.13 ng/g, signaling low-level pollution. Tetra-, penta-, and hexa-chlorinated biphenyls were dominant species in soil samples, accounting for more than 75% ofΣPCBs in the soil samples. PCB118 was the most abundant congener in all the samples. The PCB118 was about 20% ofΣPCBs. The soil organic matter content showed only a weak correlation with the levels of all PCB congeners, in which a better correlation was noted for the more volatile lighter PCB congeners than for the heavier homologues. To a certain extent, the sources and land use seemed to influence the levels of PCBs. 相似文献
760.
海滨浴场的卫生细菌学调查及保护对策 总被引:1,自引:0,他引:1
张丽艳 《辽宁城乡环境科技》1998,18(6):6-7
从卫生细菌学角度,选用总大量菌群作为指标,对多年的海浴场监测结果进行了综合分析,以期了解近年来秦皇岛海滨浴场的水质变化情况,并提出了可行的保护对策。 相似文献