全文获取类型
收费全文 | 4314篇 |
免费 | 632篇 |
国内免费 | 598篇 |
专业分类
安全科学 | 588篇 |
废物处理 | 24篇 |
环保管理 | 612篇 |
综合类 | 2343篇 |
基础理论 | 817篇 |
污染及防治 | 208篇 |
评价与监测 | 319篇 |
社会与环境 | 423篇 |
灾害及防治 | 210篇 |
出版年
2024年 | 99篇 |
2023年 | 155篇 |
2022年 | 157篇 |
2021年 | 198篇 |
2020年 | 168篇 |
2019年 | 166篇 |
2018年 | 150篇 |
2017年 | 229篇 |
2016年 | 252篇 |
2015年 | 230篇 |
2014年 | 199篇 |
2013年 | 297篇 |
2012年 | 413篇 |
2011年 | 391篇 |
2010年 | 291篇 |
2009年 | 266篇 |
2008年 | 218篇 |
2007年 | 260篇 |
2006年 | 244篇 |
2005年 | 214篇 |
2004年 | 132篇 |
2003年 | 137篇 |
2002年 | 101篇 |
2001年 | 95篇 |
2000年 | 93篇 |
1999年 | 84篇 |
1998年 | 42篇 |
1997年 | 37篇 |
1996年 | 44篇 |
1995年 | 27篇 |
1994年 | 42篇 |
1993年 | 25篇 |
1992年 | 15篇 |
1991年 | 18篇 |
1990年 | 13篇 |
1989年 | 7篇 |
1988年 | 2篇 |
1987年 | 4篇 |
1986年 | 4篇 |
1985年 | 2篇 |
1984年 | 5篇 |
1983年 | 1篇 |
1982年 | 2篇 |
1981年 | 4篇 |
1980年 | 5篇 |
1978年 | 1篇 |
1977年 | 1篇 |
1973年 | 1篇 |
1972年 | 1篇 |
1971年 | 1篇 |
排序方式: 共有5544条查询结果,搜索用时 15 毫秒
851.
852.
Elie Gaget Diego Pavón-Jordán Alison Johnston Aleksi Lehikoinen Wesley M. Hochachka Brett K. Sandercock Alaaeldin Soultan Hichem Azafzaf Nadjiba Bendjedda Taulant Bino Luka Božič Preben Clausen Mohamed Dakki Koen Devos Cristi Domsa Vitor Encarnação Kiraz Erciyas-Yavuz Sándor Faragó Teresa Frost Clemence Gaudard Lívia Gosztonyi Fredrik Haas Menno Hornman Tom Langendoen Christina Ieronymidou Vasiliy A. Kostyushin Lesley J. Lewis Svein-Håkon Lorentsen Leho Luigujõe Włodzimierz Meissner Tibor Mikuska Blas Molina Zuzana Musilová Viktor Natykanets Jean-Yves Paquet Nicky Petkov Danae Portolou Jozef Ridzoň Samir Sayoud Marko Šćiban Laimonas Sniauksta Antra Stīpniece Nicolas Strebel Norbert Teufelbauer Goran Topić Danka Uzunova Andrej Vizi Johannes Wahl Marco Zenatello Jon E. Brommer 《Conservation biology》2021,35(3):834-845
Climate warming is driving changes in species distributions and community composition. Many species have a so-called climatic debt, that is, shifts in range lag behind shifts in temperature isoclines. Inside protected areas (PAs), community changes in response to climate warming can be facilitated by greater colonization rates by warm-dwelling species, but also mitigated by lowering extirpation rates of cold-dwelling species. An evaluation of the relative importance of colonization-extirpation processes is important to inform conservation strategies that aim for both climate debt reduction and species conservation. We assessed the colonization-extirpation dynamics involved in community changes in response to climate inside and outside PAs. To do so, we used 25 years of occurrence data of nonbreeding waterbirds in the western Palearctic (97 species, 7071 sites, 39 countries, 1993–2017). We used a community temperature index (CTI) framework based on species thermal affinities to investigate species turnover induced by temperature increase. We determined whether thermal community adjustment was associated with colonization by warm-dwelling species or extirpation of cold-dwelling species by modeling change in standard deviation of the CTI (CTISD). Using linear mixed-effects models, we investigated whether communities in PAs had lower climatic debt and different patterns of community change than communities outside PAs. For CTI and CTISD combined, communities inside PAs had more species, higher colonization, lower extirpation, and lower climatic debt (16%) than communities outside PAs. Thus, our results suggest that PAs facilitate 2 independent processes that shape community dynamics and maintain biodiversity. The community adjustment was, however, not sufficiently fast to keep pace with the large temperature increases in the central and northeastern western Palearctic. Our results underline the potential of combining CTI and CTISD metrics to improve understanding of the colonization-extirpation patterns driven by climate warming. 相似文献
853.
Wildlife provides food, medicine, clothing, and other necessities for humans, but overexploitation can disrupt the sustainability of wildlife resources and severely threaten global biodiversity. Understanding the characteristics of consumer behavior is helpful for wildlife managers and policy makers, but the traditional survey methods are laborious and time-consuming. In contrast, culturomics may more efficiently identify the features of wildlife consumption. As a case study of the culturomics approach, we examined tiger bone wine consumption in China based on social media and Baidu search engine data. Tiger bone wine is one of the most purchased tiger products; its consumption is closely related to tiger poaching, which greatly threatens wild tiger survival. We searched a popular social media website for the term “tiger bone wine” and focused on posts that were originally created from 1 January 2012 to 31 December 2018. We filtered and classified posts related to the purchase, sale, or consumption of tiger bone wine and extracted information on providers, consumption motivations, year of production, and place of origin of the tiger bone wines based on the texts and photos of these posts. We found 756 posts related to tiger bone wine consumption, 113 of which mentioned providers of tiger bone wine, including friends (53%), elder relatives (37%), peer relatives (7%), and others (3%). Out of the 756 posts, 266 indicated the motivations of tiger bone wine consumption. Tiger bone wines were consumed as a tonic (34%), medicine (23%), game product (30%), and a symbol of wealth (28%). Some posts indicated ≥2 consumption motivations. These findings were consistent with the search queries from Baidu index. Such information could help develop targeted strategies for tiger conservation. The culturomics approach illustrated by our study is a rapid and cost-efficient way to characterize wildlife consumption. 相似文献
854.
F. Pricope Ştefănescu G. Tiţescu I. Cărăuş D. Ureche 《Environmental Chemistry Letters》2003,1(2):149-151
During the artificial reproduction of salmonides, the fecundity can be increased either by improving the viability of spermatozoa,
or by extending the time period during which a roe micropile remains open, thus allowing its fecundation. Practically, this
can be achieved by the use of some fertilising techniques suitable for fish species. Here, we show that the reproduction of
rainbow trout in a 1:1 solution of deuterium-depleted water and distilled water led to a significant increase in survival
of roes during their embryonic development. Moreover, the addition of glucose and fructose into the deuterium-depleted fertilising
solutions led to a further increase in roe survival during embryonic development. The increase in survival is mainly explained
by an increase in the motility of spermatozoa. 相似文献
855.
不同农田土壤养分可持续性指数的研究 总被引:1,自引:0,他引:1
讨论了不同农田土壤碳、氮、磷、钾养分的可持续性指数。结果表明,不同施肥方式、不同土壤类型对碳、氮养分可持续性指数的影响表现为有机肥配施化肥处理>有机肥处理>化肥处理,潮土>水稻土>红壤;对磷、钾养分表现为化肥处理>有机肥配施化肥处理>有机肥处理,水稻土>潮土>红壤。相关分析表明,土壤养分可持续性指数与土壤养分相关或极相关。这表明,土壤养分可持续性指数可以用来评价土壤肥力和指示土壤养分的动态变化。 相似文献
856.
Enrichment of potentially toxic elements in areas underlain by black shales and slates in Korea 总被引:6,自引:0,他引:6
Jin-Soo Lee Hyo-Taek Chon Jong-Shin Kim Kyoung-Woong Kim Hi-Soo Moon 《Environmental geochemistry and health》1998,20(3):135-147
The Okchon black shale in Korea provides an important example of natural geological materials containing toxic elements; the Chung-Joo, Duk-Pyung, Geum-Kwan, I-Won and Chu-Bu areas are underlain by these black shales and slates of the Guryongsan Formation. This formation is part of the Okchon Group which is found in the central part of Korea. Geochemical surveys were undertaken in these five study areas in the Okchon Zone in order to examine the level of enrichment and dispersion patterns of potentially toxic elements in rocks and soils. After appropriate preparation, samples were analysed by instrumental neutron activation analysis and inductively coupled plasma atomic emission spectrometry for a range of elements. Arsenic, Cu, Mo, V, U and Zn are highly enriched in the Okchon black shales and their mean concentrations are significantly higher than those in black slates. These elements are closely associated with one another from a geochemical viewpoint and may be enriched simultaneously. Mean concentrations of As, Mo and U in soils derived from black shales occurring in the Duk-Pyung and Chu-Bu areas are higher than the permissible level suggested by Kloke (1979), and the enrichment index decreases in the order of Duk- Pyung > Chu-Bu > Chung-Joo > Geum-Kwan = I-Won areas. Uranium-bearing minerals such as uraninite and brannerite have been identified in black shales from the Chung-Joo area by electron probe micro-analysis. Uraninite grains are closely associated with monazite and pyrite with a grain size ranging from 2m to 10m whereas brannerite grains occur as a euhedral form 50m in diameter. 相似文献
857.
南岳衡山风景名胜区景观资源的调查与评价 总被引:4,自引:0,他引:4
景观资源是旅游资源的重要组成因素,本文以自然综合体的南岳衡山为考察对象,对其景观资源进行较详尽的调查,并进行定性和定量的评价,为确定南岳衡山风景名胜区性质、规划提供基础资料. 相似文献
858.
重庆市可持续发展指标体系的设计和评价 总被引:14,自引:0,他引:14
刘渝琳 《城市环境与城市生态》1999,12(4):30-32,45
本文从可持续发展目标出发,建立反映重庆市可持续发展的存量,质量,结构与变动度指标体系,应用层次分析法,模糊综合评判法及功效系数法对重庆市可持续发展进行了定量分析,并确定了可持续发展的满意值和不允许值。力图为重庆市可持续发展指标体系的评价和理论研究提供一套可行的方法。 相似文献
859.
流域湿地是流域生态系统中河岸陆地和河道水体间的水陆过渡地带,在污染物阻控、生物多样性保护、侵蚀泥沙削减等方面有着重要的作用。为揭示辽河流域干流上、中、下游湿地污染物削减特征,量化比较湿地水质净化功能的差异,在对东西辽河交汇口湿地、七星湿地和下游湿地水质及水量进行现场监测的基础上,采用内梅罗污染指数法对其污染状况进行分析,实证评估湿地对污染物的去除效果。结果表明,内梅罗污染指数在支流入口处较高,经过湿地净化作用,在湿地中部及出口处污染程度明显降低;东西辽河交汇口湿地、七星湿地和下游湿地对污染物的去除效果有所差异,这主要是受支流和流域水污染的结构性、复合性、区域性等特征因素影响的结果。 相似文献
860.