全文获取类型
收费全文 | 745篇 |
免费 | 37篇 |
国内免费 | 4篇 |
专业分类
安全科学 | 42篇 |
废物处理 | 121篇 |
环保管理 | 119篇 |
综合类 | 110篇 |
基础理论 | 175篇 |
环境理论 | 4篇 |
污染及防治 | 122篇 |
评价与监测 | 36篇 |
社会与环境 | 44篇 |
灾害及防治 | 13篇 |
出版年
2023年 | 6篇 |
2022年 | 10篇 |
2021年 | 16篇 |
2020年 | 14篇 |
2019年 | 18篇 |
2018年 | 30篇 |
2017年 | 28篇 |
2016年 | 40篇 |
2015年 | 33篇 |
2014年 | 19篇 |
2013年 | 60篇 |
2012年 | 30篇 |
2011年 | 46篇 |
2010年 | 39篇 |
2009年 | 45篇 |
2008年 | 38篇 |
2007年 | 45篇 |
2006年 | 40篇 |
2005年 | 27篇 |
2004年 | 21篇 |
2003年 | 15篇 |
2002年 | 17篇 |
2001年 | 9篇 |
2000年 | 9篇 |
1999年 | 11篇 |
1998年 | 8篇 |
1997年 | 8篇 |
1996年 | 8篇 |
1995年 | 6篇 |
1994年 | 3篇 |
1993年 | 6篇 |
1992年 | 6篇 |
1991年 | 10篇 |
1990年 | 5篇 |
1989年 | 4篇 |
1986年 | 6篇 |
1984年 | 2篇 |
1981年 | 2篇 |
1979年 | 2篇 |
1972年 | 2篇 |
1971年 | 2篇 |
1961年 | 3篇 |
1959年 | 2篇 |
1958年 | 2篇 |
1957年 | 5篇 |
1955年 | 5篇 |
1954年 | 2篇 |
1940年 | 2篇 |
1934年 | 1篇 |
1926年 | 1篇 |
排序方式: 共有786条查询结果,搜索用时 77 毫秒
631.
632.
Peter J. McDonald Catherine E. M. Nano Simon J. Ward Alistair Stewart Chris R. Pavey Gary W. Luck Chris R. Dickman 《Conservation biology》2017,31(5):1183-1191
A prevailing view in dryland systems is that mammals are constrained by the scarcity of fertile soils and primary productivity. An alternative view is that predation is a primary driver of mammal assemblages, especially in Australia, where 2 introduced mesopredators—feral cat (Felis catus) and red fox (Vulpes vulpes)—are responsible for severe declines of dryland mammals. We evaluated productivity and predation as drivers of native mammal assemblage structure in dryland Australia. We used new data from 90 sites to examine the divers of extant mammal species richness and reconstructed historic mammal assemblages to determine proportional loss of mammal species across broad habitat types (landform and vegetation communities). Predation was supported as a major driver of extant mammal richness, but its effect was strongly mediated by habitat. Areas that were rugged or had dense grass cover supported more mammal species than the more productive and topographically simple areas. Twelve species in the critical weight range (CWR) (35–5500 g) that is most vulnerable to mesopredator predation were extirpated from the continent's central region, and the severity of loss of species correlated negatively with ruggedness and positively with productivity. Based on previous studies, we expect that habitat mediates predation from red foxes and feral cats because it affects these species’ densities and foraging efficiency. Large areas of rugged terrain provided vital refuge for Australian dryland mammals, and we predict such areas will support the persistence of CWR species in the face of ongoing mammal declines elsewhere in Australia. 相似文献
633.
634.
635.
F. Vidogbéna A. Adégbidi R. Tossou F. Assogba-Komlan T. Martin M. Ngouajio S. Simon L. Parrot S. T. Garnett K. K. Zander 《Environment, Development and Sustainability》2016,18(6):1749-1770
If agro-ecological systems are to realize their potential as sustainable alternatives to conventional agricultural systems, innovation diffusion needs to be enhanced. We conducted surveys among 214 small-scale vegetable farmers in Benin, a food-deficit country in West Africa, on how they perceived the different attributes of eco-friendly nets (EFNs). The nets act as physical barriers against insects in vegetable production and so reduce pesticide use. Understanding farmer perceptions about new technologies helps reveal farmers’ propensity to adopt them. Intensity of attitude was measured on a Likert scale, and an ordered probit model was used to determine which characteristics of nets were most influential. Eighteen percent of farmers thought that EFNs would benefit them, but almost half preferred not to adopt this technology at all. The main reason for rejecting the nets was the perceived high labor requirement, particularly on larger plots of land. This largely negative perception was strongest among farmers with large areas cultivated with vegetables, farmers who had little or no experience in a trial, and those living far from extension services. We recommend expanded trials that engage a higher proportion of farmers, strengthening of external support for those wanting to use the nets and further technological development to reduce labor costs, improved access to finance and increased education about the negative impacts of insecticides abuse. 相似文献
636.
637.
638.
639.
Jessica Betts Richard P. Young Craig Hilton-Taylor Michael Hoffmann Jon Paul Rodríguez Simon N. Stuart E.J. Milner-Gulland 《Conservation biology》2020,34(3):632-643
The International Union for Conservation of Nature (IUCN) Red List of Threatened Species, a species extinction risk assessment tool, has been guiding conservation efforts for over 5 decades. It is widely assumed to have been instrumental in preventing species from moving closer to extinction and driving recoveries. However, the impact of the IUCN Red List in guiding conservation has not been evaluated. We conducted, transcribed, and coded interviews with experts who use the IUCN Red List across a range of sectors to understand how the list is used in conservation. We developed a theory of change to illustrate how and why change is expected to occur along causal pathways contributing to the long-term goal of the IUCN Red List and an evaluation framework with indicators for measuring the impact of the IUCN Red List in generating scientific knowledge, raising awareness among stakeholders, designating priority conservation sites, allocating funding and resources, influencing development of legislation and policy, and guiding targeted conservation action (key themes). Red-list assessments were the primary input leading to outputs (scientific knowledge, raised awareness), outcomes (better informed priority setting, access to funding and resource availability, improved legislation and policy), and impact (implemented conservation action leading to positive change) that have resulted in achievement of IUCN Red List goals. To explore feasibility of attributing the difference made by the IUCN Red List across themes, we studied increased scientific knowledge, raised awareness, access to funding and resource allocation, and increased conservation activity. The feasibility exploration showed increased scientific knowledge over time identified through positive trends in publications referring to the IUCN Red List in the literature; raised awareness of the list following high IUCN activity identified by peaks in online search activity; an increased proportion of conservation funding bodies requesting IUCN Red List status in the application process; and, based on interviews with Amphibian Specialist Group members, red-list assessments were essential in connecting relevant stakeholders and ensuring conservation action. Although we identified the IUCN Red List as a vital tool in global conservation efforts, it was challenging to measure specific impacts because of its ubiquitous nature. We are the first to identify the influence of the IUCN Red List on conservation. 相似文献
640.