全文获取类型
收费全文 | 1792篇 |
免费 | 17篇 |
国内免费 | 23篇 |
专业分类
安全科学 | 46篇 |
废物处理 | 62篇 |
环保管理 | 245篇 |
综合类 | 401篇 |
基础理论 | 347篇 |
环境理论 | 1篇 |
污染及防治 | 512篇 |
评价与监测 | 95篇 |
社会与环境 | 109篇 |
灾害及防治 | 14篇 |
出版年
2023年 | 20篇 |
2022年 | 18篇 |
2021年 | 29篇 |
2020年 | 21篇 |
2019年 | 25篇 |
2018年 | 47篇 |
2017年 | 50篇 |
2016年 | 60篇 |
2015年 | 72篇 |
2014年 | 77篇 |
2013年 | 84篇 |
2012年 | 80篇 |
2011年 | 115篇 |
2010年 | 97篇 |
2009年 | 99篇 |
2008年 | 90篇 |
2007年 | 98篇 |
2006年 | 80篇 |
2005年 | 54篇 |
2004年 | 80篇 |
2003年 | 44篇 |
2002年 | 62篇 |
2001年 | 68篇 |
2000年 | 30篇 |
1999年 | 17篇 |
1998年 | 17篇 |
1997年 | 25篇 |
1996年 | 19篇 |
1995年 | 31篇 |
1994年 | 19篇 |
1993年 | 6篇 |
1992年 | 14篇 |
1991年 | 24篇 |
1990年 | 11篇 |
1989年 | 18篇 |
1988年 | 7篇 |
1987年 | 4篇 |
1985年 | 5篇 |
1984年 | 5篇 |
1982年 | 10篇 |
1981年 | 10篇 |
1979年 | 9篇 |
1970年 | 6篇 |
1969年 | 4篇 |
1966年 | 3篇 |
1965年 | 4篇 |
1962年 | 3篇 |
1960年 | 4篇 |
1959年 | 3篇 |
1954年 | 3篇 |
排序方式: 共有1832条查询结果,搜索用时 0 毫秒
201.
Harper LA Sharpe RR Parkin TB De Visscher A van Cleemput O Byers FM 《Journal of environmental quality》2004,33(4):1189-1201
Ammonia (NH(3)) emissions from animal systems have become a primary concern for all of livestock production. The purpose of this research was to establish the relationship of nitrogen (N) emissions to specific components of swine production systems and to determine accurate NH(3) emission factors appropriate for the regional climate, geography, and production systems. Micrometeorological instrumentation and gas sensors were placed over two lagoons in North Carolina during 1997-1999 to obtain information for determining ammonia emissions over extended periods and without interfering with the surrounding climate. Ammonia emissions varied diurnally and seasonally and were related to lagoon ammonium concentration, acidity, temperature, and wind turbulence. Conversion of significant quantities of ammonium NH(4)(+) to dinitrogen gas (N(2)) were measured in all lagoons with the emission rate largely dependent on NH(4)(+) concentration. Lagoon NH(4)(+) conversion to N(2) accounted for the largest loss component of the N entering the farm (43% as N(2)); however, small amounts of N(2)O were emitted from the lagoon (0.1%) and from field applications (0.05%) when effluent was applied nearby. In disagreement with previous and current estimates of NH(3) emissions from confined animal feeding operation (CAFO) systems, and invalidating current assumptions that most or all emissions are in the form of NH(3), we found much smaller NH(3) emissions from animal housing (7%), lagoons (8%), and fields (2%) using independent measurements of N transformation and transport. Nitrogen input and output in the production system were evaluated, and 95% of input N was accounted for as output N from the system. 相似文献
202.
Claudia Voelckel Tamara Krügel Klaus Gase Nadja Heidrich Nicole M. van Dam Robert Winz Ian T. Baldwin 《Chemoecology》2001,11(3):121-126
203.
Bodar CW Berthault F de Bruijn JH van Leeuwen CJ Pronk ME Vermeire TG 《Chemosphere》2003,53(8):1039-1047
An evaluation was performed on the first group (41) of completed risk assessments for chemicals of the EU priority lists (Existing Chemicals; EC Regulation 793/93). The evaluation focussed on the conclusions of the risk assessments. The EU risk assessment process detected a high number of substances of concern. Furthermore priority chemicals may pose potential risks to the whole range of protection goals of the risk assessment. The predictability of the risk assessments for priority chemicals was investigated. Our a priori knowledge on possible risks of priority chemicals is found to be poor, especially for consumers. Both for environment and human health the potential risks were linked with a broad spectrum of use patterns. It is concluded that no industry category can in advance be excluded from performing risk assessments. For a great number of chemicals, additional testing was found to be needed to finalize the risk assessment. This evokes questions about the completeness of the current base-set, but also about the suitability of some of the submitted human health tests that should initially fulfil the base-set needs. The results of this evaluation are useful for ongoing discussions on risk assessment processes for chemicals. 相似文献
204.
205.
206.
207.
Mark E. Eiswerth G. Cornelis van Kooten 《Journal of the American Water Resources Association》2019,55(5):1335-1348
Given the expansion of payments for water‐based ecosystem services (PWES) worldwide, two relevant issues are as follows: (1) determination of efficient allocations of payments among land managers, and (2) how this might change when paying one manager to implement a best management practice (BMP) to enhance an ecosystem service impacts the cost‐effectiveness of BMPs considered by other land managers not currently involved in PWES. Such externalities may be negative if diminishing returns dominate, or positive if mechanisms such as “social diffusion” dominate. We analyze how a planner should optimally allocate payments, depending on whether the expected externalities are negligible, negative, or positive. We employ (1) an optimal control model to gain insights on the problem’s dynamics, and (2) stochastic dynamic programming to determine optimal funding strategies using a specific application. The study contributes to the literature by identifying dynamically optimal PWES payment patterns, and illustrates how they should change when one accounts for externalities induced by the program. Because such impacts have not been addressed previously in a rigorous way, this treatment provides useful value added for PWES design and implementation. 相似文献
208.
Although many parasites are known to manipulate the behavior of their hosts, the mechanisms underlying such manipulations are largely unknown. Baculoviruses manipulate the behavior of caterpillar hosts by inducing hyperactivity and by inducing climbing behavior leading to death at elevated positions (tree-top disease or Wipfelkrankheit). Whether hyperactivity and tree-top disease are independent manipulative strategies of the virus is unclear. Recently, we demonstrated the involvement of the protein tyrosine phosphatase (ptp) gene of the baculovirus Autographa californica multiple nucleopolyhedrovirus (AcMNPV) in the induction of hyperactivity in Spodoptera exigua larvae. Here we show that AcMNPV ptp is not required for tree-top disease, indicating that in S. exigua baculovirus-induced hyperactivity and tree-top disease are independently induced behaviors that are governed by distinct mechanisms. 相似文献
209.
Hesti Lestari Tata Meine van Noordwijk Denis Ruysschaert Rachmat Mulia Subekti Rahayu Elok Mulyoutami Atiek Widayati Andree Ekadinata Riswan Zen Adji Darsoyo Rahayu Oktaviani Sonya Dewi 《Mitigation and Adaptation Strategies for Global Change》2014,19(6):693-713
Tripa is the last remaining peat-swamp forest that harbours a potentially viable Sumatran orangutan (Pongo abelii) sub-population in a formally but not effectively protected area. It appears to be a simple showcase where current efforts to financially support reducing emissions from deforestation and forest degradation (REDD+) converge with biodiversity and social co-benefits. In practice, however, situation is more complex. REDD+ efforts interact with global palm oil trade and regulatory approaches (the moratorium) to achieve national goals for emissions reduction under umbrella of nationally appropriate mitigation actions (NAMA). To contextualize this debate, we assessed (i) land-use history and formal basis of palm-oil companies’ rights; (ii) carbon (C) stocks, historical emission levels and potential emissions that can be avoided; (iii) economic benefits of land-use options and opportunity costs of avoiding emissions; (iv) biodiversity and environmental services; and (v) alternative options for “high C stock development” and employment generation. Natural forest cover declined (54 % in 1995, 18 % in 2009) while oil palm increased 4–39 %. Aboveground C stocks decreased from 148 Mg ha?1 in 1990 to 61 Mg ha?1 in 2009, leading to average annual emissions of 14.5 Mg (carbon dioxide) CO2e ha?1 year?1. While 41 % of these emissions yield less than American Dollar (USD) 5 of current economic benefits per Mg CO2e emitted and might be compensated by REDD+, nearly all new emissions derive from a breach of existing laws, regulations and voluntary palm-oil standards. Substantial investment in alternative employment is needed, rather than carbon payments per se, to support livelihoods in a low carbon emissions economy. 相似文献
210.
Victoria A. Braithwaite Felicity Huntingford Ruud van den Bos 《Journal of Agricultural and Environmental Ethics》2013,26(1):7-23
Increasing public concern for the welfare of fish species that human beings use and exploit has highlighted the need for better understanding of the cognitive status of fish and of their ability to experience negative emotions such as pain and fear. Moreover, studying emotion and cognition in fish species broadens our scientific understanding of how emotion and cognition are represented in the central nervous system and what kind of role they play in the organization of behavior. For instance, on a macro neuro-architecture level the brains of fish species look dramatically different from those of mammals, while such a dramatic difference does not (always) occur at the level of emotion- and cognition-related behavior. Here, therefore, we discuss the evidence of emotion and cognition in fish species related to underlying neuro-architecture and the role that emotion and cognition play in the organization of behavior. To do so we use a framework encompassing a number of steps allowing a systematic approach to these issues. Emotion and cognition confer on human and non-human animals the capacity to compliment and/or override immediate reflexes to stimuli and so allow a large degree of flexibility in behavior. Systematic research on behavior that in mammals is indicative of emotion and cognition has been conducted in only a few fish species. The data thus far indicate that in these species brain-behavior relationships are not fundamentally different from those observed in mammals. Furthermore, data from other studies show evidence that behavior patterns related to emotion and cognition vary between fish species as well within fish species, related to sex and life history stage for example. From a welfare perspective, knowledge of such variability will potentially help us to design optimal living conditions for fish species kept by humans. 相似文献