全文获取类型
收费全文 | 9887篇 |
免费 | 3篇 |
国内免费 | 8篇 |
专业分类
安全科学 | 10篇 |
废物处理 | 802篇 |
环保管理 | 1230篇 |
综合类 | 964篇 |
基础理论 | 3133篇 |
污染及防治 | 1825篇 |
评价与监测 | 1030篇 |
社会与环境 | 901篇 |
灾害及防治 | 3篇 |
出版年
2023年 | 3篇 |
2022年 | 3篇 |
2021年 | 7篇 |
2020年 | 3篇 |
2019年 | 1篇 |
2018年 | 1477篇 |
2017年 | 1375篇 |
2016年 | 1197篇 |
2015年 | 129篇 |
2014年 | 18篇 |
2013年 | 60篇 |
2012年 | 467篇 |
2011年 | 1359篇 |
2010年 | 698篇 |
2009年 | 608篇 |
2008年 | 894篇 |
2007年 | 1240篇 |
2006年 | 14篇 |
2005年 | 31篇 |
2004年 | 41篇 |
2003年 | 80篇 |
2002年 | 108篇 |
2001年 | 24篇 |
2000年 | 14篇 |
1999年 | 6篇 |
1998年 | 10篇 |
1997年 | 1篇 |
1996年 | 2篇 |
1995年 | 1篇 |
1994年 | 1篇 |
1993年 | 1篇 |
1992年 | 1篇 |
1991年 | 1篇 |
1987年 | 1篇 |
1984年 | 11篇 |
1983年 | 8篇 |
1975年 | 1篇 |
1935年 | 2篇 |
排序方式: 共有9898条查询结果,搜索用时 127 毫秒
31.
Andreas Züttel 《Mitigation and Adaptation Strategies for Global Change》2007,12(3):343-365
Hydrogen storage and transportation or distribution is closely linked together. Hydrogen can be distributed continuously in
pipelines or batch wise by ships, trucks, railway or airplanes. All batch transportation requires a storage system but also
pipelines can be used as pressure storage system. Hydrogen exhibits the highest heating value per weight of all chemical fuels.
Furthermore, hydrogen is regenerative and environment friendly. There are two reasons why hydrogen is not the major fuel of
toady’s energy consumption: First of all, hydrogen is just an energy carrier. And, although it is the most abundant element
in the universe, it has to be produced, since on earth it only occurs in the form of water. This implies that we have to pay
for this energy, which results in a difficult economic task, because since the industrialization we are used to consuming
energy for free. The second difficulty with hydrogen as an energy carrier is the low critical temperature of 33 K, i.e. hydrogen
is a gas at room temperature. For mobile and in many cases also for stationary applications the volumetric and gravimetric
density of hydrogen in a storage system is crucial. Hydrogen can be stored by six different methods and phenomena: high pressure
gas cylinders (up to 800 bar), liquid hydrogen in cryogenic tanks (at 21 K), adsorbed hydrogen on materials with a large specific
surface area (at T < 100 K), absorbed on interstitial sites in a host metal (at ambient pressure and temperature), chemically bond in covalent
and ionic compounds (at ambient pressure), oxidation of reactive metals e.g. Li, Na, Mg, Al, Zn with water. These metals easily
react with water to the corresponding hydroxide and liberate the hydrogen from the water. Finally, the metal hydroxides can
be thermally reduced to the metals in a solar furnace. 相似文献
32.
FUENSANTA CARAVACA DINO FIGUEROA ANTONIO ROLDÁn CONCEPCIÓN AZCÓN-AGUILAR 《Environmental management》2003,31(3):0412-0420
The reestablisment of autochthonous plant species is an essential strategy for recovering degraded areas under semiarid conditions.
A field experiment was carried out to assess the short-term effect of two reafforestation methods involving mycorrhizal inoculation
and compost addition on soil quality parameters and Rhamnus lycioides seedling growth. The nutrient content (NPK) and enzymatic activities (dehydrogenase, urease, protease-BAA, acid phosphatase
and β-glucosidase) increased and bulk density decreased in the rhizosphere soil with the organic amendment. Biomass C of rhizosphere
soil increased by at least 240% with respect to the control soil after mycorrhizal inoculation and the combination of compost
addition + mycorrhizal inoculation. Both mycorrhizal inoculation and composted organic residue addition increased R. lycioides seedling growth in the same proportion. In the short term, we conclude that the application of both reafforestation methods
not only enhances the establishment of R. lycioides seedlings, but also improves soil quality. 相似文献
33.
Jiang Xue-Gong Shen Jian-Guo Liu Jing-Tao Chung Yong-Seung 《Water, Air, & Soil Pollution: Focus》2003,3(2):191-212
By using observational data and MM5, an observational analysisand numerical study was conducted on the synoptic condition of a severe dust storm that was caused by a Mongolian cyclone whichoccurred from 6 to 8 April 2001. Results illustrated thatthe cyclogenesis was due to the isentropic potential vorticity (IPV) advection in the upper troposphere and the terrain modifiedbaroclinicity in the mid-lower troposphere. The Altai-Sayan complex of mountains blocked the lower level cold air and made the isentropic surface sharply steep. When the air slid down along the isentropic surface the increasing of baroclinicity anddecreasing of stability blew up the vertical vorticity development.The formation of the dust storm was a result of a cyclonic cold front passing across the area. The occurrence of this dust stormwas closely related to the strong surface wind, which was accompanied by a cold front passing, rather than the cyclogenesis, itself. Hence, the reason for the pre-front dust storm formulation was the formation of heating convection. Reasons behind the formation of a black storm (visibilitylower than 50 m), which occurred in the mid-north part ofInner Mongolia, lay in several aspects. Firstly, in thisarea the surface wind was strong, a direct result of thedownward transport in mid-lower troposphere. Secondly,the cold front passed over the effected area near sunsetso the air obtained much more surface heating to form adeeper mixed layer (ML). Thirdly, cooperation between thelower level wind and the terrain made the atmosphere inthis area and acquired the maximum advective contributionnecessary to form a deep post-front ML. The sensitivityexperiment revealed that surface heat flux was important to the frontal lifting. In addition, the forcing of surface heating wasalso seen as the primary forcing mechanism of frontogenesis. Meanwhile, removal of the surface heat flux made the atmosphericstratification became stable and the pre-storm ML very shallow,which weakened the strength of the dust storm. 相似文献
34.
Wang Xu Ma Yu Chen Hongwu Wen Gang Chen Shoujun Tao Zuyu Chung Yong-Seung 《Water, Air, & Soil Pollution: Focus》2003,3(2):67-79
With observational data spanning 1961–1999 from 90 meteorological stations in Xinjiang, China, the spatial and temporal characteristics of sandstorms and strong winds, and the contribution of strong winds to the occurrence of sandstormsare analyzed. Moreover, the dominant wind direction and minimumwind speeds during sandstorm periods are discussed. The research shows that although possessing similar climatic trends, sandstorms and strong winds in Xinjiang have opposite geographical distributions, i.e. places with more sandstorms show fewer strong winds. The contribution of strongwinds to sandstorms in northern Xinjiang is larger than that insouthern Xinjiang. The dominant wind directions clearly indicatethe paths of the weather systems that introduced the sandstorms.The minimum wind speeds in the sandstorms were over 10 ms-1in northern and eastern Xinjiang and in the Turpan and Yanqi Basins of southern Xinjiang. In Tarim Basin of southern Xinjiang,however, the minimum wind speed was about 6–8 ms-1, and even 6 ms-1 at its southern edge. 相似文献
35.
36.
Jagannadha Rao Matta John Kerr Kimberly Chung 《Journal of Environmental Planning and Management》2005,48(4):475-490
Despite the critical role of government agencies in decentralizing natural resource governance, little work to date has focused on the organizational aspects of the responsible government bureaucracies. Based on a qualitative investigation of the perspectives of Forest Department employees involved in India's Joint Forest Management (JFM) program, this paper aims to provide an understanding of these internal dynamics. Elaborating on why bureaucracies with a learning orientation are essential if participatory natural resource management is to succeed, the paper underlines the constraints to transforming forest agencies' hierarchical work cultures. Foresters describe JFM as a radical departure from traditional forest governance, but suggest that corresponding transformation within the Forest Department has not occurred. Foresters cite as reasons: (1) a target-based incentive system that leaves little room for establishing the relationships with local people needed for collaborative management; (2) rigid rules and regulations that prevent the flexibility needed for adaptive, site-specific problem-solving; (3) a hierarchical, top-down style of communication that prevents the upper administration from learning what is happening on the ground and stifles initiative by field staff; (4) the need for a committed leadership to reverse this hierarchical culture. They point to the few such team-oriented leaders as the key to transforming the Forest Department and enabling participatory forest management to succeed. The authors also recommend accompanying changes in training and reward systems. 相似文献
37.
38.
Biochar physicochemical parameters as a result of feedstock material and pyrolysis temperature: predictable for the fate of biochar in soil? 总被引:1,自引:0,他引:1
39.
Nguyen Kim Nga Huynh Dang Chinh Phi Thi Thuy Hong Tran Quang Huy 《Journal of Polymers and the Environment》2017,25(2):146-155
This study aimed at finding effective strategies for high-performance removal of reactive blue 19 (RB19) dye from aqueous solution. Chitosan (CS) films had been prepared by using solvent casting with mild drying for this purpose. The CS films were characterized by X-ray diffraction, field-emission scanning electron microscopy, and Fourier transform infrared (FTIR) spectroscopy. The performance of RB19 removal using CS were evaluated by varying contact time, solution pH, initial dye concentration, and adsorbent dosage. Adsorption isotherms, kinetics, and desorption were investigated by batch experiments. Results showed that CS films exhibited the optimal adsorption performance for RB19 removal and high maximum adsorption capacities of RB19, which were 799 and 822.4 mg g?1 at 20 and 40 °C, respectively. Adsorption kinetic data were well described by the pseudo-second-order kinetic model. FTIR analyses further indicated that interactions between RB19 and the CS film occurred during adsorption. The CS films also exhibited satisfactory desorption of RB19 at about 80 % after 30 min of desorption at pH 11. Our study demonstrated that the CS films can be easily prepared and applied for effective removal of RB19 in treatment of wastewater. 相似文献
40.
Christian Mougin Agnès Bouchez Laurence Denaix Isabelle Lamy François Laurent Fabrice Martin-Laurent Michel Mench 《Environmental science and pollution research international》2016,23(4):2974-2976
The fifth meeting of INRA’s national network of ecotoxicologists took place on 25 to 27 November 2014 in Biarritz, France. The main aim of the meeting was to bring together ecotoxicologists from INRA and associated partners, providing them ample opportunity to share and discuss their latest scientific results as well as the national policy of research in ecotoxicology and to precise perspectives for the network. 相似文献