全文获取类型
收费全文 | 40230篇 |
免费 | 393篇 |
国内免费 | 354篇 |
专业分类
安全科学 | 1107篇 |
废物处理 | 1526篇 |
环保管理 | 5217篇 |
综合类 | 7237篇 |
基础理论 | 10951篇 |
环境理论 | 26篇 |
污染及防治 | 10265篇 |
评价与监测 | 2588篇 |
社会与环境 | 1811篇 |
灾害及防治 | 249篇 |
出版年
2022年 | 288篇 |
2021年 | 261篇 |
2019年 | 293篇 |
2018年 | 548篇 |
2017年 | 541篇 |
2016年 | 787篇 |
2015年 | 658篇 |
2014年 | 972篇 |
2013年 | 2921篇 |
2012年 | 1179篇 |
2011年 | 1689篇 |
2010年 | 1388篇 |
2009年 | 1419篇 |
2008年 | 1667篇 |
2007年 | 1745篇 |
2006年 | 1580篇 |
2005年 | 1348篇 |
2004年 | 1320篇 |
2003年 | 1270篇 |
2002年 | 1235篇 |
2001年 | 1627篇 |
2000年 | 1113篇 |
1999年 | 719篇 |
1998年 | 534篇 |
1997年 | 551篇 |
1996年 | 556篇 |
1995年 | 611篇 |
1994年 | 566篇 |
1993年 | 497篇 |
1992年 | 531篇 |
1991年 | 506篇 |
1990年 | 510篇 |
1989年 | 516篇 |
1988年 | 461篇 |
1987年 | 377篇 |
1986年 | 359篇 |
1985年 | 398篇 |
1984年 | 372篇 |
1983年 | 412篇 |
1982年 | 410篇 |
1981年 | 364篇 |
1980年 | 306篇 |
1979年 | 344篇 |
1978年 | 300篇 |
1977年 | 264篇 |
1976年 | 270篇 |
1975年 | 253篇 |
1974年 | 249篇 |
1973年 | 239篇 |
1972年 | 272篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
371.
Bioconversion of dairy manure by black soldier fly (Diptera: Stratiomyidae) for biodiesel and sugar production 总被引:1,自引:0,他引:1
Modern dairies cause the accumulation of considerable quantity of dairy manure which is a potential hazard to the environment. Dairy manure can also act as a principal larval resource for many insects such as the black soldier fly, Hermetia illucens. The black soldier fly larvae (BSFL) are considered as a new biotechnology to convert dairy manure into biodiesel and sugar. BSFL are a common colonizer of large variety of decomposing organic material in temperate and tropical areas. Adults do not need to be fed, except to take water, and acquired enough nutrition during larval development for reproduction. Dairy manure treated by BSFL is an economical way in animal facilities. Grease could be extracted from BSFL by petroleum ether, and then be treated with a two-step method to produce biodiesel. The digested dairy manure was hydrolyzed into sugar. In this study, approximately 1248.6 g fresh dairy manure was converted into 273.4 g dry residue by 1200 BSFL in 21 days. Approximately 15.8 g of biodiesel was gained from 70.8 g dry BSFL, and 96.2 g sugar was obtained from the digested dairy manure. The residual dry BSFL after grease extraction can be used as protein feedstuff. 相似文献
372.
Environmental assessment of garden waste management in the Municipality of Aarhus, Denmark 总被引:1,自引:0,他引:1
An environmental assessment of six scenarios for handling of garden waste in the Municipality of Aarhus (Denmark) was performed from a life cycle perspective by means of the LCA-model EASEWASTE. In the first (baseline) scenario, the current garden waste management system based on windrow composting was assessed, while in the other five scenarios alternative solutions including incineration and home composting of fractions of the garden waste were evaluated. The environmental profile (normalised to Person Equivalent, PE) of the current garden waste management in Aarhus is in the order of −6 to 8 mPE Mg−1 ww for the non-toxic categories and up to 100 mPE Mg−1 ww for the toxic categories. The potential impacts on non-toxic categories are much smaller than what is found for other fractions of municipal solid waste. Incineration (up to 35% of the garden waste) and home composting (up to 18% of the garden waste) seem from an environmental point of view suitable for diverting waste away from the composting facility in order to increase its capacity. In particular the incineration of woody parts of the garden waste improved the environmental profile of the garden waste management significantly. 相似文献
373.
N. Mithil Kumar K. Varaprasad G. Ramachandra Reddy G. Siva Mohan Reddy Y. Sivabharathi G. Venkata Subba Reddy S. Venkata Naidu 《Journal of Polymers and the Environment》2011,19(1):225-229
Synthesis and characterization of novel biodegradable, water soluble and optically active DL-malic acid (DMA) and citric acid
(CA) copolymers were studied for possible use as antibacterial agents. The copolymers were synthesized by direct bulk melt
condensation in the absence of a catalyst above 150 °C. Characterization of obtained copolymers was carried out with the help
of infrared absorption spectra, differential scanning calorimetry and thermo gravimetric analysis. The antibacterial activity
of copolymers against bacteria was investigated. The results obtained shows the above copolymers possess a broad wound dressing
activity against different types of bacteria and may be useful as antibacterial agents. 相似文献
374.
J. Lelieveld P. Hadjinicolaou E. Kostopoulou C. Giannakopoulos A. Pozzer M. Tanarhte E. Tyrlis 《Regional Environmental Change》2014,14(5):1937-1949
The eastern Mediterranean and Middle East, a region with diverse socioeconomic and cultural identities, is exposed to strong climatic gradients between its temperate north and arid south. Model projections of the twenty-first century indicate increasing hot weather extremes and decreasing rainfall. We present model results, which suggest that across the Balkan Peninsula and Turkey climate change is particularly rapid, and especially summer temperatures are expected to increase strongly. Temperature rise can be amplified by the depletion of soil moisture, which limits evaporative cooling, prompted by the waning of large-scale weather systems that generate rain. Very hot summers that occurred only rarely in the recent past are projected to become common by the middle and the end of the century. Throughout the region, the annual number of heat wave days may increase drastically. Furthermore, conditions in the region are conducive for photochemical air pollution. Our model projections suggest strongly increasing ozone formation, a confounding health risk factor particularly in urban areas. This adds to the high concentrations of aerosol particles from natural (desert dust) and anthropogenic sources. The heat extremes may have strong impacts, especially in the Middle East where environmental stresses are plentiful. 相似文献
375.
376.
S. J. Metcalf E. I. van Putten S. D. Frusher M. Tull N. Marshall 《Sustainability Science》2014,9(3):247-261
Identifying effective adaptation strategies for coastal communities dependent on marine resources and impacted by climate change can be difficult due to the dynamic nature of marine ecosystems. The task is more difficult if current and predicted shifts in social and economic trends are considered. Information about social and economic change is often limited to qualitative data. A combination of qualitative and quantitative models provide the flexibility to allow the assessment of current and future ecological and socio-economic risks and can provide information on alternative adaptations. Here, we demonstrate how stakeholder input, qualitative models and Bayesian belief networks (BBNs) can provide semi-quantitative predictions, including uncertainty levels, for the assessment of climate and non-climate-driven change in a case study community. Issues are identified, including the need to increase the capacity of the community to cope with change. Adaptation strategies are identified that alter positive feedback cycles contributing to a continued decline in population, local employment and retail spending. For instance, the diversification of employment opportunities and the attraction of new residents of different ages would be beneficial in preventing further population decline. Some impacts of climate change can be combated through recreational bag or size limits and monitoring of popular range-shifted species that are currently unmanaged, to reduce the potential for excessive removal. Our results also demonstrate that combining BBNs and qualitative models can assist with the effective communication of information between stakeholders and researchers. Furthermore, the combination of techniques provides a dynamic, learning-based, semi-quantitative approach for the assessment of climate and socio-economic impacts and the identification of potential adaptation strategies. 相似文献
377.
378.
379.
380.