全文获取类型
收费全文 | 22453篇 |
免费 | 1617篇 |
国内免费 | 2871篇 |
专业分类
安全科学 | 2923篇 |
废物处理 | 410篇 |
环保管理 | 3874篇 |
综合类 | 12626篇 |
基础理论 | 1936篇 |
环境理论 | 17篇 |
污染及防治 | 1246篇 |
评价与监测 | 1131篇 |
社会与环境 | 1832篇 |
灾害及防治 | 946篇 |
出版年
2024年 | 87篇 |
2023年 | 326篇 |
2022年 | 538篇 |
2021年 | 739篇 |
2020年 | 778篇 |
2019年 | 577篇 |
2018年 | 475篇 |
2017年 | 718篇 |
2016年 | 808篇 |
2015年 | 852篇 |
2014年 | 990篇 |
2013年 | 1284篇 |
2012年 | 1486篇 |
2011年 | 1679篇 |
2010年 | 1177篇 |
2009年 | 1273篇 |
2008年 | 979篇 |
2007年 | 1531篇 |
2006年 | 1561篇 |
2005年 | 1330篇 |
2004年 | 1180篇 |
2003年 | 1064篇 |
2002年 | 963篇 |
2001年 | 798篇 |
2000年 | 753篇 |
1999年 | 696篇 |
1998年 | 444篇 |
1997年 | 409篇 |
1996年 | 262篇 |
1995年 | 278篇 |
1994年 | 203篇 |
1993年 | 198篇 |
1992年 | 124篇 |
1991年 | 83篇 |
1990年 | 58篇 |
1989年 | 27篇 |
1988年 | 36篇 |
1987年 | 16篇 |
1986年 | 11篇 |
1985年 | 13篇 |
1984年 | 21篇 |
1983年 | 18篇 |
1982年 | 12篇 |
1981年 | 10篇 |
1980年 | 15篇 |
1979年 | 16篇 |
1974年 | 6篇 |
1973年 | 7篇 |
1972年 | 5篇 |
1971年 | 13篇 |
排序方式: 共有10000条查询结果,搜索用时 125 毫秒
881.
E.V. Antonakou K.G. Kalogiannis S.D. Stephanidis K.S. Triantafyllidis A.A. Lappas D.S. Achilias 《Waste management (New York, N.Y.)》2014,34(12):2487-2493
Pyrolysis appears to be a promising recycling process since it could convert the disposed polymers to hydrocarbon based fuels or various useful chemicals. In the current study, two model polymers found in WEEEs, namely polycarbonate (PC) and high impact polystyrene (HIPS) and their counterparts found in waste commercial Compact Discs (CDs) were pyrolysed in a bench scale reactor. Both, thermal pyrolysis and pyrolysis in the presence of two catalytic materials (basic MgO and acidic ZSM-5 zeolite) was performed for all four types of polymers. Results have shown significant recovery of the monomers and valuable chemicals (phenols in the case of PC and aromatic hydrocarbons in the case of HIPS), while catalysts seem to decrease the selectivity towards the monomers and enhance the selectivity towards other desirable compounds. 相似文献
882.
利用自动连续监测仪器对在成都市城区选定的监测点位开展了持续数日的测量,获取了测点的长时间监测数据,通过对监测数据的分析,研究了0.1~3000MHz射频电磁环境随时间变化的规律及其与人群作息时间的关系,并对电磁环境人工手动监测的适宜时间段进行了分析。 相似文献
883.
Damon M. Hall Gerardo R. Camilo Rebecca K. Tonietto Jeff Ollerton Karin Ahrné Mike Arduser John S. Ascher Katherine C. R. Baldock Robert Fowler Gordon Frankie Dave Goulson Bengt Gunnarsson Mick E. Hanley Janet I. Jackson Gail Langellotto David Lowenstein Emily S. Minor Stacy M. Philpott Simon G. Potts Muzafar H. Sirohi Edward M. Spevak Graham N. Stone Caragh G. Threlfall 《Conservation biology》2017,31(1):24-29
Research on urban insect pollinators is changing views on the biological value and ecological importance of cities. The abundance and diversity of native bee species in urban landscapes that are absent in nearby rural lands evidence the biological value and ecological importance of cities and have implications for biodiversity conservation. Lagging behind this revised image of the city are urban conservation programs that historically have invested in education and outreach rather than programs designed to achieve high‐priority species conservation results. We synthesized research on urban bee species diversity and abundance to determine how urban conservation could be repositioned to better align with new views on the ecological importance of urban landscapes. Due to insect pollinators’ relatively small functional requirements—habitat range, life cycle, and nesting behavior—relative to larger mammals, we argue that pollinators put high‐priority and high‐impact urban conservation within reach. In a rapidly urbanizing world, transforming how environmental managers view the city can improve citizen engagement and contribute to the development of more sustainable urbanization. 相似文献
884.
Protected areas (PAs) and payments for ecosystem services (PES) are the top two mechanisms available for countries to achieve international REDD agreements, yet there are few empirical comparisons of their effects. We estimate the impacts of PAs and PES on forest conservation, poverty reduction, and population change at the locality level in Mexico in the 2000s. Both policies conserved forest, generating an approximately 20–25% reduction in expected forest cover loss. PES created statistically significant but small poverty alleviation while PAs had overall neutral impacts on livelihoods. Estimates by individual policy type for the same level of deforestation risk indicate that biosphere reserves and PES balanced conservation and livelihood goals better than strict protected areas or mixed-use areas. This suggests that both direct and incentive-based instruments can be effective, and that policies combining sustainable financing, flexible zoning, and recognition of local economic goals are more likely to achieve conservation without harming livelihoods. 相似文献
885.
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
886.
Xueqi Fan Jie Gao Wenchao Li Jun Huang Gang Yu 《Frontiers of Environmental Science & Engineering》2020,14(1):8
887.
IntroductionWith the development of industries and increased diversity of their associated hazards, the importance of identifying these hazards and controlling the Occupational Health and Safety (OHS) risks has also dramatically augmented. Currently, there is a serious need for a risk management system to identify and prioritize risks with the aim of providing corrective/preventive measures to minimize the negative consequences of OHS risks. In fact, this system can help the protection of employees’ health and reduction of organizational costs. Method: The present study proposes a hybrid decision-making approach based on the Failure Mode and Effect Analysis (FMEA), Fuzzy Cognitive Map (FCM), and Multi-Objective Optimization on the basis of Ratio Analysis (MOORA) for assessing and prioritizing OHS risks. After identifying the risks and determining the values of the risk assessment criteria via the FMEA technique, the attempt is made to determine the weights of criteria based on their causal relationships through FCM and the hybrid learning algorithm. Then, the risk prioritization is carried out using the MOORA method based on the decision matrix (the output of the FMEA) and the weights of the criteria (the output of the FCM). Results: The results from the implementation of the proposed approach in a manufacturing company reveal that the score at issue can overcome some of the drawbacks of the traditional Risk Priority Number (RPN) in the conventional FMEA, including lack of assignment the different relative importance to the assessment criteria, inability to take into account other important management criteria, lack of consideration of causal relationships among criteria, and high dependence of the prioritization on the experts’ opinions, which finally provides a full and distinct risk prioritization. 相似文献
888.
889.
本文主要针对大气环境中PM2.5展开深入研究和论述,先介绍了大气环境中PM2.5的定义和危害,然后结合重量法、光散射法以及β射线吸收法等,对PM2.5的检测技术进行了深入分析,最后提出了几点治理措施,比如加大法治建设和政府监管力度、降低机动车尾气排放、控制工业废气排放、增加植被、加强区域联防联控机制的构建等,以对大气环境中PM2.5含量进行合理化控制,并将空气污染指数保持在可控范围内,避免大气环境污染问题的出现。 相似文献
890.
Lanndon A. Ocampo Eppie E. Clark Michael Angelo B. Promentilla 《International Journal of Sustainable Engineering》2016,9(5):305-314
The growing industrial interest in adopting sustainability programmes has ushered in studies regarding sustainability indicators which have continually flourished in current literature. However, limited attention is given to the development of priority ranking, which is an important input for any adopting firm. This paper presents a hybrid multi-criteria approach in determining priority areas in sustainable manufacturing (SM). Using fuzzy analytic hierarchy process to address uncertainty in hierarchical decision-making, this paper determines SM priority strategies and eventually identifies even lower level strategies. The computed sustainable manufacturing index is presented at both the organizational and operational levels for a real case study of an industrial plastic manufacturing firm. This work provides a detailed and transparent hierarchical decision-making approach based on SM framework, the use of which could be valuable to practicing managers across industries in their pursuit of greater sustainability. 相似文献