全文获取类型
收费全文 | 977篇 |
免费 | 117篇 |
国内免费 | 348篇 |
专业分类
安全科学 | 42篇 |
废物处理 | 52篇 |
环保管理 | 185篇 |
综合类 | 740篇 |
基础理论 | 89篇 |
环境理论 | 3篇 |
污染及防治 | 105篇 |
评价与监测 | 64篇 |
社会与环境 | 162篇 |
出版年
2024年 | 12篇 |
2023年 | 61篇 |
2022年 | 61篇 |
2021年 | 72篇 |
2020年 | 62篇 |
2019年 | 51篇 |
2018年 | 58篇 |
2017年 | 66篇 |
2016年 | 89篇 |
2015年 | 93篇 |
2014年 | 70篇 |
2013年 | 112篇 |
2012年 | 85篇 |
2011年 | 121篇 |
2010年 | 32篇 |
2009年 | 43篇 |
2008年 | 37篇 |
2007年 | 39篇 |
2006年 | 36篇 |
2005年 | 27篇 |
2004年 | 32篇 |
2003年 | 25篇 |
2002年 | 32篇 |
2001年 | 31篇 |
2000年 | 30篇 |
1999年 | 14篇 |
1998年 | 10篇 |
1997年 | 12篇 |
1996年 | 9篇 |
1995年 | 9篇 |
1994年 | 2篇 |
1993年 | 1篇 |
1991年 | 3篇 |
1990年 | 1篇 |
1988年 | 1篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1977年 | 1篇 |
排序方式: 共有1442条查询结果,搜索用时 15 毫秒
41.
Melike E. Bildirici 《Natural resources forum》2020,44(4):289-310
In this paper, the life span of hydro and nuclear energy generations and the relationship between hydro and nuclear energy generations, environmental pollution, and economic growth were investigated for Japan covering the period of 1960–2018 by employing the Bathtub-Weibull curve and Markov switching-vector error correcting (MSVEC) method, respectively. According to the Bathtub-Weibull curve analysis, a rising failure rate for nuclear energy was found, indicating that the life of nuclear energy has expired, but a decreasing failure rate for hydroelectric energy has been detected. Then two different MSVEC models were used. The MSVEC method, unlike traditional approaches, determines the relationship between variables under different regimes. The results of MSVEC methods indicate three important points. First, regime-dependent asymmetry and regime changes are crucial for policy recommendations. Second, the shocks to hydropower and nuclear energy generations cause temporary deviations from the long-run growth path in both regimes. Lastly, the increase in hydropower generation leads to a decrease in environmental pollution and an increase in GDP, and an increase in nuclear power generation increases pollution and growth in both regimes. 相似文献
42.
Based on the data of 30 Chinese provinces for the period from 2004 to 2015, this paper expounds the carbon emissions effect of two-way foreign direct investment (FDI) from the perspective of scale effect and factor market distortions. This study uses Kaya identity to decompose carbon emission and construct simultaneous equations model to empirically examine the factor market distortion and the carbon emission scale effect of two-way FDI. The results show that the inward foreign direct investment (IFDI) increase regional carbon emission through scale effect and also exacerbates factor market distortion in China, whereas the outward FDI trends reduce carbon emission and reduces factor market distortions in China. The study also shows that human capital, research and development (R&D), trade openness, and capital accumulation are important determinants of two-way FDI. Therefore, the study proposes that IFDI policies should focus on acquiring green technologies. In addition, the domestic enterprises should be encouraged to participate in global business. 相似文献
43.
44.
Akira KONDO Esrom HAMONANGAN Satoshi SODA Akikazu KAGA Yoshio INOUE Masaharu EGUCHI Yuta YASAKA 《环境科学学报(英文版)》2007,19(6):709-713
Total suspended particulate mater (TSP) concentrations were monitored for one year from July 2000 and for one year from April 2003 in Jakarta City. Thirteen elemental TSP components, aluminum (Al), sodium (Na), iron (Fe), lead (Pb), potassium (K), zinc (Zn), titanium (Ti), manganese (Mn), bromine (Br), copper (Cu), chromium (Cr), nickel (Ni), and vanadium (V) were analyzed by a sequential X-ray fluorescence spectrometer. Al, Na, Fe, K, and Pb were major components at most of the sampling locations in 2000. However, only Pb in 2003 dramatically decreased to one tenth. The phase-out of leaded gasoline began on July 1, 2001 in Jakarta City and lead content in gasoline decreased to one tenth, too. The decrease in Pb concentration was a result of the phase-out of leaded gasoline, as lead emissions mainly are exhaust gas from vehicles. 相似文献
45.
刘丽萍 《中国人口.资源与环境》2011,(Z1)
根据云南省能源消费量,计算了由能源消费产生的CO2排放量及单位GDP碳排放强度。结果表明:近10年来,随着社会经济的快速发展,云南省能源消费及能源消费导致的CO2排放总量也呈现出显著上升的趋势。云南的碳排放强度高于全国平均水平,但人均碳排放量低于全国平均水平。以工业为主的第二产业是能源消费及碳排放的主体,其碳排放占总量的75%。 相似文献
46.
Paul A.Steenhof 《中国人口.资源与环境(英文版)》2005,3(2)
1 INTRODUCTIONEnergy and environmental issues in China have receivedsignificant attention in both the peer-reviewed literatureand in international energy and environmental policymaking in the last number of years. China's coal dominatedenergy consumption results in significant regional pollutionproblems, most notably acid rain that affects nearly 1/3rdof China's landmass and air pollution that plagues manyof its major cities. China now ranks as the top emitterof sulphur dioxide (SO2) pol… 相似文献
47.
John Rice 《Journal of Environmental Planning and Management》2016,59(1):44-61
Recent climate change projections and a push towards a universal agreement on carbon emission reductions suggest that firms will need to respond to future regulatory changes. This paper employs an influencing strategies lens to examine how large-scale firms might respond to future climate change regulations. The study uses a structured qualitative methodology to explore and explicate the strategic responses from 21 international firms to the proposed emissions trading scheme outlined in Australia's Garnaut Climate Change Review. The results of the analysis show that firms can use pre-emptive influencing strategies in attempts to shape and mould regulatory design parameters, secure high levels of transitional economic support, and shift the balance of public policies and expenditure. Complementary defensive strategies may also target policy makers and regulators with some of the potential negative consequences of the new regulations. 相似文献
48.
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
49.
Giorgio Zamboni Silvia Marelli Giulio Marmorato Massimo Capobianco 《International Journal of Green Energy》2016,13(5):481-488
A cooperative fuel research (CFR) engine was modified and instrumented in order to control operating conditions and to measure engine parameters and in-cylinder pressure diagrams. Aiming at the comparison of different alternative fuels, an experimental procedure was defined, including cetane number (CN) evaluation and the definition of engine operating quantities in different working points, for fixed levels of compression ratio (CR) and injection advance. An investigation was made considering several blends of methyl-esters of rapeseed oil (RME) and of a mix of vegetable oils (VOME) with conventional diesel oil. The defined experimental procedure was applied to assess CN, engine brake thermal efficiency (bte) and exhaust emissions. Results show that the biodiesel content has a positive influence on soot emissions, with strong reduction, while thermal efficiency and NOX emissions are negatively affected, which can be justified taking into account fuel properties and changes in combustion process. As observed outcomes are generally in line with those presented in literature, the facility proved to be a suitable tool for basic investigations on alternative fuels to be used in specific applications. 相似文献
50.
G. Suresh H. C. Kamath Mallikarjun Bhovi 《International Journal of Sustainable Engineering》2016,9(3):206-214
Increased petroleum prices, increased threat to the environment from exhaust emissions and global warming have generated intense international interest in developing renewable and alternative non-petroleum fuels for internal combustion engines. Evolving suitable technology for addressing energy crisis creates a continued investigation into the search for sustainable and clean-burning renewable fuels. This work investigates suitability of different non-edible-derived biodiesels such as cotton seed oil methyl ester (COME), Honne oil methyl ester (HnOME) and Rubber seed oil methyl ester (RuOME) to four stroke, single cylinder compression ignition (CI) engine. Engine tests were conducted to study the effect of fuel blending, thermal barrier coating (TBC) or Low Heat Rejection (LHR) and injector nozzle geometry on the performance, combustion and emission characteristics of COME, HnOME and RuOME in the modified CI engine. Blends of biodiesels with diesel were varied from 20 to 80% in steps of 20%. Two thermal barrier coatings of partially stabilized zirconium (PSZ) and aluminium oxide (Al2O3) were provided on the engine to make it fully adiabatic. Nozzle injectors of 3, 4 and 5 holes, with size of orifice varied from 0.2 to 0.3 mm size were selected for the study. It was concluded that B20 biodiesel blend, PSZ-coated engine and four hole nozzle injector of 0.2 mm size resulted in overall better engine performance with increased brake thermal efficiency (BTE) and reduced HC, CO, smoke emissions for the fuel combinations tested. Combustion analysis to study the effect of biodiesel blends, LHR coatings, injector nozzle geometry on the performance of the biodiesel-fuelled engine has been presented to give more insight into the behaviour of operation. 相似文献