全文获取类型
收费全文 | 4678篇 |
免费 | 33篇 |
国内免费 | 37篇 |
专业分类
安全科学 | 126篇 |
废物处理 | 271篇 |
环保管理 | 385篇 |
综合类 | 724篇 |
基础理论 | 978篇 |
环境理论 | 3篇 |
污染及防治 | 1478篇 |
评价与监测 | 438篇 |
社会与环境 | 322篇 |
灾害及防治 | 23篇 |
出版年
2023年 | 48篇 |
2022年 | 135篇 |
2021年 | 152篇 |
2020年 | 75篇 |
2019年 | 72篇 |
2018年 | 158篇 |
2017年 | 167篇 |
2016年 | 222篇 |
2015年 | 131篇 |
2014年 | 219篇 |
2013年 | 366篇 |
2012年 | 245篇 |
2011年 | 311篇 |
2010年 | 196篇 |
2009年 | 166篇 |
2008年 | 254篇 |
2007年 | 248篇 |
2006年 | 175篇 |
2005年 | 198篇 |
2004年 | 210篇 |
2003年 | 195篇 |
2002年 | 153篇 |
2001年 | 110篇 |
2000年 | 52篇 |
1999年 | 50篇 |
1998年 | 20篇 |
1997年 | 33篇 |
1996年 | 22篇 |
1995年 | 33篇 |
1994年 | 24篇 |
1993年 | 19篇 |
1992年 | 13篇 |
1991年 | 22篇 |
1990年 | 19篇 |
1989年 | 14篇 |
1988年 | 11篇 |
1987年 | 12篇 |
1986年 | 8篇 |
1985年 | 10篇 |
1984年 | 10篇 |
1983年 | 14篇 |
1982年 | 6篇 |
1981年 | 9篇 |
1979年 | 9篇 |
1967年 | 6篇 |
1964年 | 12篇 |
1963年 | 9篇 |
1962年 | 8篇 |
1958年 | 10篇 |
1956年 | 5篇 |
排序方式: 共有4748条查询结果,搜索用时 31 毫秒
51.
The Science of Nature - 相似文献
52.
Dr J. L. Carrasco Juan A. Otero Gómez M. C. Vilar Mesa J. L. García Miranda J. M. Troyano Luque O. Morales Ruiz J. Parache Hernández 《黑龙江环境通报》1989,9(6):443-445
A dicentric X chromosome was found in a female fetus during cytogenetic studies performed on amniotic cells. Blood samples from the parents showed normal karyotypes and the pregnancy was terminated. The mechanism for the formation of this ‘de novo’ rearrangement is discussed. 相似文献
53.
D. Costa A. Borrell E. Margarit A. Carrió A. Soler I. Balmes X. Estivill A. Fortuny 《黑龙江环境通报》1995,15(2):141-148
Fluid from pleural effusion (n=2) and cystic hygroma (n=7) was obtained from eight fetuses, between 13 and 32 weeks of pregnancy at the time when a conventional prenatal diagnosis procedure was carried out. As these fluids contain lymphocytes, they were processed like peripheral blood. A karyotype was obtained in 4 days in both cases of pleural effusion and in four out of seven samples of cystic hygroma. An abnormal karyotype was detected in three of the four samples of cystic hygroma: two trisomies 21 and a monosomy X. Different parameters were evaluated in order to predict the feasibility of obtaining a cytogenetic diagnosis. Our data showed that if the amount of fluid obtained was ⩾4 ml and the initial lymphocyte count (ILC) was >0.2 × 106 cells/ml, a cytogenetic diagnosis was possible from an initial concentration of cultured lymphocytes )ICCL) of >0.06 × 106 cells/ml. 相似文献
54.
Kevin Summers Leroy Folmar Miriam Rodón-Naveira 《Environmental monitoring and assessment》1997,47(3):275-301
As part of the Environmental Monitoring and Assessment Programin 1991, the field efficacy of six research indicators wasexamined in the estuarine systems of the Gulf of Mexico. Theutility of these indicators was tested by examining thoseresponses at both ends of multiple environmental gradients;namely, under minimally impacted conditions (reference) andheavily impacted conditions (by hypoxia, industrialdischarges, agricultural runoff). In addition, the geographiceffects of location (east and west of the Mississippi River)were examined. Numbers and frequencies of pathologies,abundance of splenic macrophage aggregates, and vertebralabnormalities showed response patterns that suggest widerfield testing along full gradients rather than simply theextremes of the gradient are warranted. Selected bloodproteins showed some promise but logistical constraints inestuarine environments may limit its utility. Concentrationsof selected organic compounds in bile showed no differences inthis study between references and contaminated sites.Molecular bioindicators are discussed with regard to theirpotential utility as indicators of ecosystem conditions. Ofthese potential indicators, the use of vitellogenin assays asa measure of reproductive impairment and frequency of shelldisease in selected crustaceans as an indicator ofimmunological aberrations deserve further examination. 相似文献
55.
Goyet Cde V 《Disasters》1993,17(2):169-176
56.
López Gappa J Tablado A Magaldi NH 《Environmental pollution (Barking, Essex : 1987)》1993,82(2):157-165
Seasonal changes in structure of a rocky intertidal community affected by sewage pollution at Quequén (Argentina) were studied over a period of 2 years. Most species showed a decrease in cover values in the polluted area. On the other hand, a small proportion of organisms favoured by organic enrichment predominated around the outfall during the period of study. Community structure was not significantly altered by frosts or windstorms. Desiccation is identified as the main physical stress. A combination of late spring high temperatures with extreme midday low-tides caused by northerly winds was responsible for heavy losses in dominant algae. Major seasonal changes in community structure were primarily due to variations in area covered by the chlorophyte Ulva lactuca, and crusts of blue-green algae and diatoms in the vicinity of the outfall. Highest diversity values were attained during either late winter or spring, due to increased abundances of several seasonal algae. Abundance of the dominant organism, the bivalve Brachidontes rodriguezi, remained stable, showing only slight, non-seasonal, changes. Since the absence of B. rodriguezi is an indication of heavy pollution, temporal stability of this species suggests that the intensity of sewage discharges did not vary over the period of study. 相似文献
57.
58.
59.
60.
Tamim Younos Raymond de Leon Christine Lewicki 《Journal of the American Water Resources Association》2003,39(1):1-5
ABSTRACT: The objective of this article is to open a dialogue on integrating service‐learning into community based watershed management programs and to discuss opportunities and challenges that a service‐learning program presents to universities and communities. The article presents the concept and definition of service‐learning, and arguments concerning why institutions of higher education and university faculty and students should be involved with community based watershed management programs. The article describes a case study for developing a service‐learning program for watershed management at Virginia Tech and discusses lessons learned from the case study. The paper concluded that to make a service‐learning program sustainable, there should be a long term plan, regular and effective communication with the stakeholders, and some incentives for faculty and students for long term commitment to the community based watershed management programs. 相似文献