全文获取类型
收费全文 | 40655篇 |
免费 | 371篇 |
国内免费 | 298篇 |
专业分类
安全科学 | 972篇 |
废物处理 | 1835篇 |
环保管理 | 5249篇 |
综合类 | 5897篇 |
基础理论 | 11427篇 |
环境理论 | 14篇 |
污染及防治 | 10142篇 |
评价与监测 | 2856篇 |
社会与环境 | 2700篇 |
灾害及防治 | 232篇 |
出版年
2022年 | 306篇 |
2021年 | 323篇 |
2020年 | 224篇 |
2019年 | 274篇 |
2018年 | 928篇 |
2017年 | 889篇 |
2016年 | 1168篇 |
2015年 | 628篇 |
2014年 | 917篇 |
2013年 | 3012篇 |
2012年 | 1262篇 |
2011年 | 2045篇 |
2010年 | 1605篇 |
2009年 | 1633篇 |
2008年 | 1977篇 |
2007年 | 2294篇 |
2006年 | 1462篇 |
2005年 | 1301篇 |
2004年 | 1262篇 |
2003年 | 1259篇 |
2002年 | 1227篇 |
2001年 | 1489篇 |
2000年 | 1073篇 |
1999年 | 645篇 |
1998年 | 496篇 |
1997年 | 469篇 |
1996年 | 518篇 |
1995年 | 532篇 |
1994年 | 492篇 |
1993年 | 455篇 |
1992年 | 461篇 |
1991年 | 433篇 |
1990年 | 458篇 |
1989年 | 443篇 |
1988年 | 400篇 |
1987年 | 359篇 |
1986年 | 314篇 |
1985年 | 312篇 |
1984年 | 388篇 |
1983年 | 339篇 |
1982年 | 398篇 |
1981年 | 326篇 |
1980年 | 282篇 |
1979年 | 323篇 |
1978年 | 278篇 |
1977年 | 243篇 |
1976年 | 219篇 |
1975年 | 208篇 |
1974年 | 225篇 |
1973年 | 229篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
951.
Journal of Polymers and the Environment - To optimize the phase separation temperature of poly (N-isopropylacrylamide) two monomers have been used to fabricate a series of three functional and... 相似文献
952.
953.
954.
R. Hickisch T. Hodgetts P. J. Johnson C. Sillero-Zubiri K. Tockner D.W. Macdonald 《Conservation biology》2019,33(5):1151-1163
Conservation planners need reliable information on spatial patterns of biodiversity. However, existing data sets are skewed because some ecosystems, taxa, and locations are underrepresented. We determined how many articles have been published in recent decades on the biodiversity of different countries and their constituent provinces. We searched the Web of Science catalogues Science Citation Index (SCI) and Social Science Citation Index (SSCI) for biodiversity-related articles published from 1993 to 2016 that included country and province names. We combined data on research publication frequency with other provincial-scale factors hypothesized to affect the likelihood of research activity (i.e., economic development, human presence, infrastructure, and remoteness). Areas that appeared understudied relative to the biodiversity expected based on site climate likely have been inaccessible to researchers for reasons, notably armed conflict. Geographic publication bias is of most concern in the most remote areas of sub-Saharan Africa and South America. Our provincial-scale model may help compensate for publication biases in conservation planning by revealing the spatial extent of research needs and the low cost of redoing this analysis annually. 相似文献
955.
Cara E. Brook James P. Herrera Cortni Borgerson Emma C. Fuller Pascal Andriamahazoarivosoa B. J. Rodolph Rasolofoniaina J. L. Rado Ravoavy Randrianasolo Z. R. Eli Rakotondrafarasata Hervet J. Randriamady Andrew P. Dobson Christopher D. Golden 《Conservation biology》2019,33(1):99-111
Subsistence hunting presents a conservation challenge by which biodiversity preservation must be balanced with safeguarding of human livelihoods. Globally, subsistence hunting threatens primate populations, including Madagascar's endemic lemurs. We used population viability analysis to assess the sustainability of lemur hunting in Makira Natural Park, Madagascar. We identified trends in seasonal hunting of 11 Makira lemur species from household interview data, estimated local lemur densities in populations adjacent to focal villages via transect surveys, and quantified extinction vulnerability for these populations based on species-specific demographic parameters and empirically derived hunting rates. We compared stage-based Lefkovitch with periodic Leslie matrices to evaluate the impact of regional dispersal on persistence trajectories and explored the consequences of perturbations to the timing of peak hunting relative to the lemur birth pulse, under assumptions of density-dependent reproductive compensation. Lemur hunting peaked during the fruit-abundant wet season (March–June). Estimated local lemur densities were roughly inverse to body size across our study area. Life-history modeling indicated that hunting most severely threatened the species with the largest bodies (i.e., Hapalemur occidentalis, Avahi laniger, Daubentonia madagascariensis, and Indri indi), characterized by late-age reproductive onsets and long interbirth intervals. In model simulations, lemur dispersal within a regional metapopulation buffered extinction threats when a majority of local sites supported growth rates above the replacement level but drove regional extirpations when most local sites were overharvested. Hunt simulations were most detrimental when timed to overlap lemur births (a reality for D. madagascariensis and I. indri). In sum, Makira lemurs were overharvested. Regional extirpations, which may contribute to broad-scale extinctions, will be likely if current hunting rates persist. Cessation of anthropogenic lemur harvest is a conservation priority, and development programs are needed to help communities switch from wildlife consumption to domestic protein alternatives. 相似文献
956.
957.
Tohamy Hossam G. Gad El-Karim Dina R. El-Sayed Yasser S. 《Environmental science and pollution research international》2019,26(21):21524-21534
Environmental Science and Pollution Research - Hydroxyurea (HDU), a class of antineoplastic drugs, has a powerful efficacy in the treatment of several types of malignancies. However, it has... 相似文献
958.
Russian Journal of Ecology - Abstract—Long-term observations (1968–2019) on the dynamics of infection by the cestode Eubothrium rugosum in the burbot (Lota lota) have been performed in... 相似文献
959.
Environmental Geochemistry and Health - This study measured both PM10 and surface dust concentrations at roadside in the Central Business District of Baguio City. A total of 66 PM10 filters and 25... 相似文献
960.
Céline Jézéquel Pablo A. Tedesco William Darwall Murilo S. Dias Renata G. Frederico Max Hidalgo Bernard Hugueny Javier Maldonado-Ocampo Koen Martens Hernan Ortega Gislene Torrente-Vilara Jansen Zuanon Thierry Oberdorff 《Conservation biology》2020,34(4):956-965
Conserving freshwater habitats and their biodiversity in the Amazon Basin is a growing challenge in the face of rapid anthropogenic changes. We used the most comprehensive fish-occurrence database available (2355 valid species; 21,248 sampling points) and 3 ecological criteria (irreplaceability, representativeness, and vulnerability) to identify biodiversity hotspots based on 6 conservation templates (3 proactive, 1 reactive, 1 representative, and 1 balanced) to provide a set of alternative planning solutions for freshwater fish protection in the Amazon Basin. We identified empirically for each template the 17% of sub-basins that should be conserved and performed a prioritization analysis by identifying current and future (2050) threats (i.e., degree of deforestation and habitat fragmentation by dams). Two of our 3 proactive templates had around 65% of their surface covered by protected areas; high levels of irreplaceability (60% of endemics) and representativeness (71% of the Amazonian fish fauna); and low current and future vulnerability. These 2 templates, then, seemed more robust for conservation prioritization. The future of the selected sub-basins in these 2 proactive templates is not immediately threatened by human activities, and these sub-basins host the largest part of Amazonian biodiversity. They could easily be conserved if no additional threats occur between now and 2050. 相似文献