全文获取类型
收费全文 | 17277篇 |
免费 | 124篇 |
国内免费 | 112篇 |
专业分类
安全科学 | 410篇 |
废物处理 | 742篇 |
环保管理 | 1940篇 |
综合类 | 3301篇 |
基础理论 | 3821篇 |
环境理论 | 8篇 |
污染及防治 | 4382篇 |
评价与监测 | 1185篇 |
社会与环境 | 1641篇 |
灾害及防治 | 83篇 |
出版年
2022年 | 151篇 |
2021年 | 172篇 |
2019年 | 124篇 |
2018年 | 259篇 |
2017年 | 258篇 |
2016年 | 378篇 |
2015年 | 270篇 |
2014年 | 447篇 |
2013年 | 1308篇 |
2012年 | 530篇 |
2011年 | 687篇 |
2010年 | 552篇 |
2009年 | 637篇 |
2008年 | 707篇 |
2007年 | 804篇 |
2006年 | 674篇 |
2005年 | 594篇 |
2004年 | 593篇 |
2003年 | 580篇 |
2002年 | 529篇 |
2001年 | 652篇 |
2000年 | 497篇 |
1999年 | 282篇 |
1998年 | 170篇 |
1997年 | 190篇 |
1996年 | 167篇 |
1995年 | 227篇 |
1994年 | 206篇 |
1993年 | 171篇 |
1992年 | 180篇 |
1991年 | 197篇 |
1990年 | 185篇 |
1989年 | 177篇 |
1988年 | 166篇 |
1987年 | 150篇 |
1986年 | 125篇 |
1985年 | 142篇 |
1984年 | 170篇 |
1983年 | 156篇 |
1982年 | 164篇 |
1981年 | 130篇 |
1980年 | 132篇 |
1979年 | 144篇 |
1978年 | 112篇 |
1977年 | 110篇 |
1976年 | 100篇 |
1975年 | 116篇 |
1974年 | 127篇 |
1973年 | 99篇 |
1972年 | 104篇 |
排序方式: 共有10000条查询结果,搜索用时 218 毫秒
301.
J. N. Proust J. F. Deconinck J. R. Geyssant J. P. Herbin J. P. Vidier 《Geologische Rundschau》1995,84(2):255-271
An interdisciplinary approach based on high-resolution physical stratigraphy, biostratigraphy, organic matter analysis and clay mineralogy has been applied to the mixed siliciclastic/carbonate Kimmeridgian/Tithonian deposits of the Boulonnais (north-western France). These rocks are the age-equivalents of some of the offshore marine source rocks of the North Sea and were deposited in an overall storm-dominated homoclinal ramp setting which may represent one of the most shore-proximal sediments of this age cropping out in north-western Europe. Comparison with data from the Yorkshire, Dorset, Lorraine and Aquitaine areas allows the discrimination of three major transgressive-regressive sediment packages with disconformities of interregional extent: (1) from the Baylei Zone to top Eudoxus Zone; (2) from the Autissiodorensis Zone to base Scitulus Zone; (3) from the upper Scitulus Zone to the Pectinatus Zone. The lower two regionally correlative disconformities correspond to the sequence boundaries at the top of the Eudoxus Zone and the top of the Autissiodorensis Zone, formed by high-frequency relative sea-level variations during the periods of maximum transgression of the platform. The latter disconformity (the P1 nodule bed) reflects a major tectonically induced reorganization of the north-west European intrashelf sedimentary basin, characterized by a shift in both the location of the main depocentre and the sources of sediment production. 相似文献
302.
N. V. Kovganko Zh. N. Kashkan Yu. G. Chernov S. K. Ananich S. N. Sokolov et al. 《Die Naturwissenschaften》1995,82(5):252-252
XII Ecdysone Workshop July 22–26, 1996 Barcelona, Spain 相似文献
303.
Dr. E. Gratacós P. J. Torres J. Vidal J. Font E. Antolin V. Cararach A. Fortuny 《黑龙江环境通报》1995,15(12):1109-1113
Anticardiolipin antibodies were measured in 60 pregnant women with acute parvovirus B19 infection. Test results for eight (13.3 per cent) women were positive for anticardiolipin antibody. Six of these eight women became negative later, yielding a prevalence of anticardiolipin antibodies of 3.3 per cent (2/60) 6 months after acute parvovirus B19 infection. Anticardiolipin antibody positivity was not associated with an increased risk of abortion, fetal death, or maternal complications. This study suggests that there is an elevated frequency of anticardiolipin antibodies in pregnant women with acute parvovirus B19, probably representing an epiphenomenon. However, this is not associated with an adverse maternal or perinatal outcome. 相似文献
304.
Microorganisms (bacteria, fungi) are common residents of the roots, stems and leaves of higher plants. In order to explore the dependency of plant development on the presence of epiphytic microorganisms, the achenes (seeds) of sunflower (Helianthus annuus L.) were sterilized and germinated under aseptic conditions. The sterility of the seedlings was determined with the agar impression method. In seedlings from non-sterile seeds (control) that were likewise raised in a germ-free environment, all plant organs investigated (stem, cotyledons and primary leaves) were contaminated with bacteria. Hypocotyl elongation was not affected by epiphytic microorganisms. However, the growth rates of the cotyledons and primary leaves were higher in sterile seedlings compared with the control. The implications of this differential inhibition of organ development by epiphytic bacteria that are transmitted via the outer surface of the seed coat are discussed. We conclude that epiphytes in the above-ground phytosphere are not necessary for the development of the sunflower seedling. 相似文献
305.
306.
307.
C. Sheinbaum I. Jauregui L. Rodríguez V. 《Mitigation and Adaptation Strategies for Global Change》1998,2(4):359-372
An analysis of the impacts on Mexican energy demand and associated carbon dioxide (CO2) emissions in the year 2005 due to efficient lighting in the commercial and residential sectors and cogeneration in the industrial sector is presented. Estimation of CO2 abatement costs and an incremental cost curve for CO2 mitigation options are considered. These technologies are cost effective opportunities, and together are projected to reduce CO2 emissions in 2005 by nearly 13 percent. Implementation of efficient lighting is already part of the demand side management (DSM) programs of the Mexican state-owned utility. However, there are important barriers that may hinder the implementation of large scale cogeneration plants. 相似文献
308.
309.
310.