全文获取类型
收费全文 | 17664篇 |
免费 | 142篇 |
国内免费 | 113篇 |
专业分类
安全科学 | 407篇 |
废物处理 | 659篇 |
环保管理 | 1924篇 |
综合类 | 5597篇 |
基础理论 | 3627篇 |
环境理论 | 3篇 |
污染及防治 | 4141篇 |
评价与监测 | 880篇 |
社会与环境 | 620篇 |
灾害及防治 | 61篇 |
出版年
2018年 | 201篇 |
2017年 | 194篇 |
2016年 | 285篇 |
2015年 | 217篇 |
2014年 | 318篇 |
2013年 | 1165篇 |
2012年 | 374篇 |
2011年 | 519篇 |
2010年 | 498篇 |
2009年 | 557篇 |
2008年 | 578篇 |
2007年 | 603篇 |
2006年 | 532篇 |
2005年 | 469篇 |
2004年 | 507篇 |
2003年 | 460篇 |
2002年 | 440篇 |
2001年 | 620篇 |
2000年 | 416篇 |
1999年 | 290篇 |
1998年 | 205篇 |
1997年 | 199篇 |
1996年 | 195篇 |
1995年 | 234篇 |
1994年 | 247篇 |
1993年 | 210篇 |
1992年 | 231篇 |
1991年 | 240篇 |
1990年 | 260篇 |
1989年 | 235篇 |
1988年 | 184篇 |
1987年 | 180篇 |
1986年 | 181篇 |
1985年 | 181篇 |
1984年 | 201篇 |
1983年 | 189篇 |
1982年 | 196篇 |
1981年 | 211篇 |
1980年 | 170篇 |
1979年 | 180篇 |
1978年 | 150篇 |
1974年 | 147篇 |
1973年 | 146篇 |
1968年 | 157篇 |
1967年 | 185篇 |
1966年 | 159篇 |
1965年 | 152篇 |
1964年 | 154篇 |
1963年 | 149篇 |
1962年 | 143篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
951.
Journal of Material Cycles and Waste Management - Material flow analysis (MFA) is a well-established tool for supporting decisions on nutrient management. This paper shows the importance of the... 相似文献
952.
Ümit H. Kaynar Seda Çınar Sermin Çam Kaynar Mehmet Ayvacıklı Tülin Aydemir 《Journal of Polymers and the Environment》2018,26(6):2300-2310
Nano-ZnO-chitosan bio-composite beads were prepared for the sorption of \({\text{UO}}_{2}^{{2+}}\) from aqueous media. The resulting nano-ZnO/CTS bio-composite beads were characterized by TEM, XRD etc. The sorption of \({\text{UO}}_{2}^{{2+}}\) by bio-composite beads was optimized using RSM. The correlation between four variables was modelled and studied. According to RSM data, correlation coefficients (R2?=?0.99) and probability F-values (F?=?2.24?×?10??10) show that the model fits the experimental data well. Adsorption capacity for nano-ZnO/CTS bio-composite beads was obtained at 148.7 mg/g under optimum conditions. The results indicate that nano-ZnO/CTS bio-composite beads are appropriate for the adsorption of \({\text{UO}}_{2}^{{2+}}\) ions from aqueous media. Also, the suitability of adsorption values to adsorption isotherms was researched and thermodynamic data were calculated. 相似文献
953.
Seyfi Polat Ahmet Uyumaz Emre Yilmaz Tolga Topgül H. Serdar Yücesu 《International Journal of Green Energy》2016,13(1):63-70
EGR is one of the most significant strategies for reducing especially nitrogen oxides (NOx) emissions from internal combustion engines. The thermal efficiency of spark ignition engines is lower than compression ignition engines because of its lower compression ratio. If the compression ratio is increased to obtain higher thermal efficiency, there may be a knocking tendency in spark ignition engines. EGR can be used in order to reduce NOx emissions and avoid knocking phenomena at higher compression ratios. In-cylinder temperature at the end of combustion is decreased and heat capacity of fresh charge is increased when EGR applied. Besides EGR, spark timing is another significant parameter for reducing exhaust emissions such as nitrogen oxides, and unburned hydrocarbon (UHC). In this study the effects of EGR and spark timing on spark ignition engine were investigated numerically. KIVA codes were used in order to model combustion process. The combustion process has been modeled for a single cylinder, four stroke and gasoline direct injection (GDI) spark ignition engine. The results showed that in-cylinder pressure and heat release rate decrease as EGR ratio increase. In-cylinder pressure increases with the advancing of spark timing. Advancing spark timing increases the heat release rate and in-cylinder temperature. The simulation results also showed that EGR reduced exhaust gas temperature and NOx emissions. 相似文献
954.
Maartje J. Klapwijk Anna J. M. Hopkins Louise Eriksson Maria Pettersson Martin Schroeder Åke Lindelöw Jonas Rönnberg E. Carina H. Keskitalo Marc Kenis 《Ambio》2016,45(2):223-234
Intensifying global trade will result in increased numbers of plant pest and pathogen species inadvertently being transported along with cargo. This paper examines current mechanisms for prevention and management of potential introductions of forest insect pests and pathogens in the European Union (EU). Current European legislation has not been found sufficient in preventing invasion, establishment and spread of pest and pathogen species within the EU. Costs associated with future invasions are difficult to estimate but past invasions have led to negative economic impacts in the invaded country. The challenge is combining free trade and free movement of products (within the EU) with protection against invasive pests and pathogens. Public awareness may mobilise the public for prevention and detection of potential invasions and, simultaneously, increase support for eradication and control measures. We recommend focus on commodities in addition to pathways, an approach within the EU using a centralised response unit and, critically, to engage the general public in the battle against establishment and spread of these harmful pests and pathogens. 相似文献
955.
Martyn N. Futter Lars Högbom Salar Valinia Ryan A. Sponseller Hjalmar Laudon 《Ambio》2016,45(2):188-202
We present a framework for evaluating and communicating effects of human activity on water quality in managed forests. The framework is based on the following processes: atmospheric deposition, weathering, accumulation, recirculation and flux. Impairments to water quality are characterized in terms of their extent, longevity and frequency. Impacts are communicated using a “traffic lights” metaphor for characterizing severity of water quality impairments arising from forestry and other anthropogenic pressures. The most serious impairments to water quality in managed boreal forests include (i) forestry activities causing excessive sediment mobilization and extirpation of aquatic species and (ii) other anthropogenic pressures caused by long-range transport of mercury and acidifying pollutants. The framework and tool presented here can help evaluate, summarize and communicate the most important issues in circumstances where land management and other anthropogenic pressures combine to impair water quality and may also assist in implementing the “polluter pays” principle. 相似文献
956.
Marjut Rajasilta Mikael Elfving Jari Hänninen Päivi Laine Ilppo Vuorinen Jorma Paranko 《Ambio》2016,45(2):205-214
957.
958.
959.
M. J. Bebianno S. Sroda T. Gomes P. Chan E. Bonnafe H. Budzinski F. Geret 《Environmental science and pollution research international》2016,23(6):5046-5055
The increase use of pharmaceutical compounds in veterinary practice and human population results in the ubiquitous presence of these compounds in aquatic ecosystems. Because pharmaceuticals are highly bioactive, there is concern about their toxicological effects in aquatic organisms. Therefore, the aim of this study was to assess the effects of an effluent from a psychiatric hospital (containing a complex mixture of 25 pharmaceutical compounds from eleven therapeutic classes) on the freshwater clam Corbicula fluminea using a proteomic approach. The exposure of C. fluminea to this complex effluent containing anxiolytics, analgesics, lipid regulators, beta blockers, antidepressants, antiepileptics, antihistamines, antihypertensives, antiplatelets and antiarrhythmics induced protein changes after 1 day of exposure in clam gills and digestive gland more evident in the digestive gland. These changes included increase in the abundance of proteins associated with structural (actin and tubulin), cellular functions (calreticulin, proliferating cell nuclear antigen (PCNA), T complex protein 1 (TCP1)) and metabolism (aldehyde dehydrogenase (ALDH), alcohol dehydrogenase, 6 phosphogluconate dehydrogenase). Results from this study indicate that calreticulin, PCNA, ALDH and alcohol dehydrogenase in the digestive gland and T complex protein 1 (TCP1)) and 6 phosphogluconate dehydrogenase in the gills represent useful biomarkers for the ecotoxicological characterization of psychiatric hospital effluents in this species. 相似文献