全文获取类型
收费全文 | 8281篇 |
免费 | 47篇 |
国内免费 | 75篇 |
专业分类
安全科学 | 117篇 |
废物处理 | 300篇 |
环保管理 | 589篇 |
综合类 | 2854篇 |
基础理论 | 1666篇 |
环境理论 | 9篇 |
污染及防治 | 1815篇 |
评价与监测 | 523篇 |
社会与环境 | 506篇 |
灾害及防治 | 24篇 |
出版年
2022年 | 89篇 |
2021年 | 104篇 |
2019年 | 68篇 |
2018年 | 131篇 |
2017年 | 115篇 |
2016年 | 169篇 |
2015年 | 115篇 |
2014年 | 217篇 |
2013年 | 504篇 |
2012年 | 244篇 |
2011年 | 279篇 |
2010年 | 247篇 |
2009年 | 293篇 |
2008年 | 295篇 |
2007年 | 343篇 |
2006年 | 261篇 |
2005年 | 219篇 |
2004年 | 204篇 |
2003年 | 241篇 |
2002年 | 200篇 |
2001年 | 217篇 |
2000年 | 178篇 |
1999年 | 141篇 |
1998年 | 91篇 |
1997年 | 99篇 |
1996年 | 64篇 |
1995年 | 105篇 |
1994年 | 99篇 |
1993年 | 75篇 |
1992年 | 68篇 |
1991年 | 73篇 |
1990年 | 85篇 |
1989年 | 73篇 |
1985年 | 66篇 |
1981年 | 60篇 |
1979年 | 66篇 |
1967年 | 76篇 |
1966年 | 70篇 |
1965年 | 74篇 |
1964年 | 78篇 |
1963年 | 81篇 |
1962年 | 75篇 |
1961年 | 77篇 |
1960年 | 70篇 |
1959年 | 77篇 |
1958年 | 71篇 |
1957年 | 84篇 |
1956年 | 68篇 |
1955年 | 60篇 |
1954年 | 63篇 |
排序方式: 共有8403条查询结果,搜索用时 46 毫秒
251.
252.
253.
254.
Dr. O. W. Jones Nolan E. Penn Stephen Shuchter Claire A. Stafford Teri Richards Colleen Kernahan Jennifer Gutierrez Patricia Cherkin Sylvia Reinsch Barbara Dixson 《黑龙江环境通报》1984,4(4):249-256
This article reports the results of a retrospective study designed to examine the responses of couples to genetic amniocentesis and subsequent therapeutic abortions due to birth defects. Fourteen women and 12 men were interviewed by experienced interviewers using a structured format designed by the authors, and each interview was audiotaped for later rating. The 5 raters (all women) were instructed to independently rate each interview using forms designed by the authors to elicit information about many aspects of the participant's individual responses as well as perceptions of spouse's responses to the process of pregnancy, amniocentesis, therapeutic abortion, and sequelae. Ratings of all 5 raters were conjoined and an homogeneous narrative was constructed for each interview. Results indicate, in general, that the respondent couples coped well with this experience. In fact 70 per cent of the respondent couples described their marital relationships as becoming closer as a result of their experience. Only a few participants reported long-term deleterious effects. Most couples coped by relying on relatives, friends, and occasionally, professional counsellors. In addition, most participants in this study suggested ways to improve the medical and psychological aspects of this experience. 相似文献
255.
E.O. Heady 《Agriculture, ecosystems & environment》1983,10(3):317-318
256.
257.
A high-precision seismic reflection method has been developed for investigating archeological objects which are hidden in a mud-layer of the Haddebyer Noor, a lake in front of the old Viking settlement Haithabu near Schleswig. Wooden and metallic objects larger than about 30 cm could be detected and mapped. Some of the mapped objects have been rescued by diving operations. Others, like wooden harbour constructions of unexpectedly large dimensions, and a large (second) shipwrack were left conserved in the mud. All finds provide a new picture of this old Viking settlement showing that its inhabitants had a far higher stage of development than hitherto suspected. 相似文献
258.
Christian Klixbüll Jørgensen 《Die Naturwissenschaften》1982,69(9):420-427
The “constituents” quarks and leptons of matter (with rest-mass) are compared with the historical development of “elements” in chemistry. If unsaturated quarks induce high (and at the moment unpredictable) rest-masses above l0GeV, we have a new view of nuclei comprising (2Z + N) u-quarks and (Z +2N) d-quarks in their low-energy states, without any reference to protons and neutrons as permanent building-blocks. Recent studies of quarks and possible rishons (sub-quarks) and technicolour hadrons are reviewed, and the rôle of identity and cardinality in quantum mechanics analyzed. 相似文献
259.
We use hydra as a model system to understand how growth and differentiation and, as a consequence of this, pattern formation are controlled at the molecular level. We have found that four substances control head and foot formation in hydra: an activator and an inhibitor of head formation and an activator and an inhibitor of foot formation. The two activators are peptides with molecular weights around 1000 daltons, the inhibitors are smaller in molecular weight (<500), have an overall positive charge and do not contain peptide bonds. In normal animals all four substances are present and most likely produced by nerve cells. We hope to understand how these substances act and interact to create the spatial and temporal pattern of growth and differentiation typical for hydra. 相似文献
260.