全文获取类型
收费全文 | 9921篇 |
免费 | 2篇 |
国内免费 | 7篇 |
专业分类
安全科学 | 10篇 |
废物处理 | 780篇 |
环保管理 | 1281篇 |
综合类 | 959篇 |
基础理论 | 3188篇 |
污染及防治 | 1788篇 |
评价与监测 | 1015篇 |
社会与环境 | 908篇 |
灾害及防治 | 1篇 |
出版年
2023年 | 1篇 |
2021年 | 7篇 |
2020年 | 4篇 |
2019年 | 6篇 |
2018年 | 1473篇 |
2017年 | 1376篇 |
2016年 | 1201篇 |
2015年 | 132篇 |
2014年 | 17篇 |
2013年 | 35篇 |
2012年 | 474篇 |
2011年 | 1354篇 |
2010年 | 698篇 |
2009年 | 604篇 |
2008年 | 897篇 |
2007年 | 1239篇 |
2006年 | 17篇 |
2005年 | 35篇 |
2004年 | 42篇 |
2003年 | 70篇 |
2002年 | 118篇 |
2001年 | 27篇 |
2000年 | 12篇 |
1999年 | 8篇 |
1998年 | 13篇 |
1997年 | 7篇 |
1996年 | 1篇 |
1995年 | 6篇 |
1994年 | 1篇 |
1993年 | 4篇 |
1992年 | 2篇 |
1991年 | 2篇 |
1990年 | 2篇 |
1989年 | 1篇 |
1987年 | 2篇 |
1986年 | 4篇 |
1985年 | 2篇 |
1984年 | 12篇 |
1983年 | 13篇 |
1982年 | 1篇 |
1981年 | 2篇 |
1979年 | 1篇 |
1976年 | 1篇 |
1973年 | 3篇 |
1966年 | 1篇 |
1935年 | 2篇 |
排序方式: 共有9930条查询结果,搜索用时 109 毫秒
31.
Aysen Müezzinoğlu Tolga Elbir Abdurrahman Bayram 《Environmental Engineering and Policy》1998,1(2):109-116
In this study, an inventory of air pollutant emission estimates from major air polluting sources in Turkey for period between 1985 and 2005 with 5-year intervals were estimated. Inventory covers anthropogenic sources of five major air pollutants of particulate matter, sulfur dioxide, carbon monoxide, nitrogen oxides and non-methane volatile organic compounds. Their break-down with respect to main activity sectors were shown and their distribution by the largest industrial source categories were worked out as annual estimates. This inventory and its analysis point to serious environmental implications of air pollutants and a need to develop a policy plan for reducing these emissions. 相似文献
32.
Independent teams undertook environmental monitoring of particular concentrations of major construction projects forming part of Hong Kong’s U.S. $20 billion airport infrastructure programme located in dense urban areas. The team combination of environmental specialists with experienced civil engineers enabled pragmatic mitigation measures to be developed and accepted by the construction personnel with the result that potentially significant adverse impacts were averted. The authors discuss the mechanism and success of this innovative approach. 相似文献
33.
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
34.
A laboratory scale study was conducted to assess the feasibility of the new coupling of rotating biological contactor (RBC) plus porous biomass support system (PBSS) using polyurethane foam as porous support media to biodegrade petroleum refinery wastewater. Polyurethane foam was attached on disks of two four-stage laboratory scale cascade connected RBC units.The two RBC units were operated simultaneously at different but constant, flowrates giving hydraulic loading rates of 0.01, 0.02, 0.03, 0.04 m3/m2/d in two runs keeping the same rotational speed 10 r/min throughout. Organic loading was a less controllable factor in this study.For all of the hydraulic loadings, it was found that the removal efficiency of total chemical oxygen demand (TCOD) and oil were above 80 percent. Ammonia nitrogen and phenol removal were above 90 and 80 percent respectively. The maximum biomass concentration within polyurethane foam was about 30 g/m2 in the first stage for 0.03 m3/m2/d hydraulic loading.The results show that t 相似文献
35.
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
36.
McCaffrey等估计轰燃前火灾温度方法的改进 总被引:6,自引:2,他引:6
在估计室内轰燃前火灾温度的多种方法中,McCaffrey等人提出的方法比较典型。该文根据内衬材料的热惯性对室内火灾的重要影响,在大量实验数据的基础上,对McCaffrey等人提出的这一方法进行了初步和理论上的改进;结合室内火灾的控制因素,对有机玻璃火灾的回归结果进行了进一步改进,提出了估计室内轰燃前火灾温度的新方法。 相似文献
37.
Impact of Land Use on Soluble Organic Nitrogen in Soil 总被引:5,自引:0,他引:5
Victoria B. Willett James J. Green Andrew J. Macdonald John A. Baddeley Georg Cadisch Steven M. J. Francis Keith W. T. Goulding Gary Saunders Elizabeth A. Stockdale Christine A. Watson David L. Jones 《Water, Air, & Soil Pollution: Focus》2004,4(6):53-60
Although it has been hypothesized that soluble organic nitrogen (SON) plays a central role in regulating productivity in some terrestrial ecosystems, the factors controlling the size of the SON pool in soil remain poorly understood. Therefore our principal aim in this work was to assess the impact of seven different land use systems (rough and managed grassland, deciduous and coniferous woodland, heathland, wetland and tilled land) on the size of the SON and inorganic N (NO
3
–
, NH
4
+
) pools in the surface soil layer (0–15 cm). After extraction with deionised water, we found that in most cases the size of the water extractable organic N (WEON) pool was similar in size to the inorganic N pool. In contrast, the KCl extractable organic N (KClEON) pool constituted the dominant form of soluble N in soils under all land uses, perhaps indicating that significant amounts were held on the soil exchange phase. In contrast to inorganic N, which varied significantly with land use, the size of the KClEON and WEON pool was similar for all land uses with the exception of KClEON in tilled land, where significantly lower amounts were observed. We conclude that SON constitutes an important soil N pool in a broad range of land uses, and that its role in microbial N assimilation, plant nutrition and ecosystem responses to atmospheric N deposition warrants further attention.
SAFRD, University of Newcastle, Newcastle-upon-Tyne, NE1 7RU, U.K. 相似文献
38.
Quantifying and Evaluating Ecosystem Health: A Case Study from Moreton Bay, Australia 总被引:1,自引:0,他引:1
As part of the program monitoring the ecosystem health of Moreton Bay, Queensland, Australia, we developed a means for assessing
ecosystem health that allows quantitative evaluation and spatial representations of the assessments. The management objectives
for achieving ecosystem health were grouped into ecosystem objectives, water quality objectives, and human health objectives.
For the first two groups, aspects of the ecosystem (e.g., trophic status) were identified, and an indicator was chosen for
each aspect. Reference values for each indicator were derived from management objectives and compared with the mapped survey
values. Subregions for which the indicator statistic was equal to or better than the assigned reference value are referred
to as “compliant zones.” High-resolution surface maps were created from spatial predictions on a fine hexagonal grid for each
of the indicators. Eight reporting subregions were established based on the depth and predicted residence times of the water.
Within each reporting subregion, the proportion that was compliant was calculated. These results then were averaged to create
an integrated ecosystem health index. The ratings by a team of ecosystem experts and the calculated ecosystem health indices
had good correspondence, providing assurance that the approach was internally consistent, and that the management objectives
covered the relevant biologic issues for the region. This method of calculating and mapping ecosystem health, relating it
directly to management objectives, may have widespread applicability for ecosystem assessment. 相似文献
39.
The concept of substituting bio‐diesel produced from plantations on eroded soils for conventional diesel fuel has gained wide‐spread attention in India. In recent months, the Indian central Government as well as some state governments have expressed their support for bringing marginal lands, which cannot be used for food production, under cultivation for this purpose. Jatropha curcas is a well established plant in India. It produces oil‐rich seeds, is known to thrive on eroded lands, and to require only limited amounts of water, nutrients and capital inputs. This plant offers the option both to cultivate wastelands and to produce vegetable oil suitable for conversion to bio‐diesel. More versatile than hydrogen and new propulsion systems such as fuel cell technology, bio‐diesel can be used in today's vehicle fleets worldwide and may also offer a viable path to sustainable transportation, i.e., lower greenhouse gas emissions and enhanced mobility, even in remote areas. Mitigation of global warming and the creation of new regional employment opportunities can be important cornerstones of any forward looking transportation system for emerging economies. 相似文献
40.
Land application of wastewater presents potential for ground water pollution if not properly managed. In situ breakthrough tests were conducted using potato (Solanum tuberosum L.)-processing wastewater and a Br tracer to characterize P leaching in seasonally frozen sandy outwash soils. In the first test, P and Br breakthrough were measured in a 7-m deep well following wastewater [2.94 mg L(-1) total P (TP); 280 mg L(-1) Br] application at the site that had 13.1 mg water-extractable P (WEP) kg(-1)and 94.4 mg Bray-1 P kg(-1). Bromide was detected in the well after approximately 0.4 pore volumes, but there was no P break-through after 7 pore volumes. In the second breakthrough test, wastewater containing 3.6 mg L(-1) TP and 259 mg L(-1) Br was applied on 1.5-m deep lysimeters at low (0.8 mg WEP kg(-1); 12.1 mg Bray-1 P kg(-1)) and high soil test P sites (104 mg WEP kg(-1); 585 mg Bray-1 P kg(-1)). Leachate TP concentration during the test remained constant (0.04 mg L(-1)) at the low P sites but increased from approximately 3.5 to 5.6 mg L(-1) at the high P sites. These results indicate no P leaching in low P soils, but leaching in high P soils, thus suggesting that most of the P leached at the high P sites was mainly due to desorption and dissolution of weakly adsorbed P from prior P applications. This was consistent with P transport simulations using the convective-dispersive equation. We conclude that P concentration in land-applied wastewater should be regulated based on soil test-P level plus wastewater P loading. 相似文献