全文获取类型
收费全文 | 13332篇 |
免费 | 101篇 |
国内免费 | 1346篇 |
专业分类
安全科学 | 214篇 |
废物处理 | 960篇 |
环保管理 | 1509篇 |
综合类 | 2783篇 |
基础理论 | 3761篇 |
环境理论 | 1篇 |
污染及防治 | 3234篇 |
评价与监测 | 1141篇 |
社会与环境 | 1014篇 |
灾害及防治 | 162篇 |
出版年
2023年 | 63篇 |
2022年 | 183篇 |
2021年 | 125篇 |
2020年 | 95篇 |
2019年 | 88篇 |
2018年 | 1592篇 |
2017年 | 1502篇 |
2016年 | 1337篇 |
2015年 | 331篇 |
2014年 | 313篇 |
2013年 | 374篇 |
2012年 | 779篇 |
2011年 | 1632篇 |
2010年 | 911篇 |
2009年 | 861篇 |
2008年 | 1140篇 |
2007年 | 1439篇 |
2006年 | 210篇 |
2005年 | 169篇 |
2004年 | 147篇 |
2003年 | 204篇 |
2002年 | 225篇 |
2001年 | 125篇 |
2000年 | 131篇 |
1999年 | 134篇 |
1998年 | 151篇 |
1997年 | 84篇 |
1996年 | 78篇 |
1995年 | 74篇 |
1994年 | 59篇 |
1993年 | 55篇 |
1992年 | 49篇 |
1991年 | 15篇 |
1990年 | 19篇 |
1989年 | 12篇 |
1988年 | 13篇 |
1987年 | 6篇 |
1986年 | 6篇 |
1985年 | 3篇 |
1984年 | 13篇 |
1983年 | 10篇 |
1982年 | 3篇 |
1981年 | 7篇 |
1979年 | 2篇 |
1977年 | 2篇 |
1975年 | 1篇 |
1974年 | 1篇 |
1972年 | 1篇 |
1971年 | 2篇 |
1935年 | 2篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
991.
992.
由于小型景观水体的体量和再生水补水措施的施行,其水质随环境和入水水质的变化和富营养化过程较大型水体快。由EFDC模型和WASP模型耦合建立小型浅水景观湖生态动力学模型,用实测水质数据进行参数率定与验证,可实现小型景观水体水质变化趋势的模拟,为水质管理提供决策支持。在此基础上,对民主湖在几种水质保障方案下1年的水质变化进行了模拟预测和对比,结果表明,作为富营养化程度表征的叶绿素a在空间和时间分布上均存在一定的规律性,夏季由于温度升高,叶绿素a浓度较高,说明藻类等浮游植物迅速增殖,是水质恶化水华暴发的高发期,而采取加大湖水水力循环和改善入口水质的控制方案,可使水质得到良好保障。 相似文献
993.
994.
Zhang F Gu W Xu P Tang S Xie K Huang X Huang Q 《Waste management (New York, N.Y.)》2011,31(6):1333-1338
Composting is the biological degradation and transformation of organic materials under controlled conditions to promote aerobic decomposition. To find effective ways to accelerate composting and improve compost quality, numerous methods including additive addition, inoculation of microorganisms, and the use of biosurfactants have been explored. Studies have shown that biosurfactant addition provides more favorable conditions for microorganism growth, thereby accelerating the composting process. However, biosurfactants have limited applications because they are expensive and their use in composting and microbial fertilizers is prohibited. Meanwhile, alkyl polyglycoside (APG) is considered a “green” surfactant. This study aims to determine whether APG addition into a compost reaction vessel during 28-day composting can enhance the organic matter degradation and composting process of dairy manure. Samples were periodically taken from different reactor depths at 0, 3, 5, 7, 14, 21, and 28 days. pH levels, electrical conductivity (EC), ammonium and nitrate nitrogen, seed germination indices, and microbial population were determined. Organic matter and total nitrogen were also measured.Compared with the untreated control, the sample with APG exhibited slightly increased microbial populations, such as bacteria, fungi, and actinomycetes. APG addition increased temperatures without substantially affecting compost pH and EC throughout the process. After 28 days, APG addition increased nitrate nitrogen concentrations, promoted matter degradation, and increased seed germination indices. The results of this study suggest that the addition of APG provides more favorable conditions for microorganism growth, slightly enhancing organic matter decomposition and accelerating the composting process, improving the compost quality to a certain extent. 相似文献
995.
Mehmet Berkun Egemen Aras Tugce Anılan 《Journal of Material Cycles and Waste Management》2011,13(4):305-313
As an economically developing country, Turkey has very well operated integrated solid waste management applications structured
on modern facilities, besides over 2,000 scattered open dump areas in the country. Integrated waste management applications
seem eligible for the metropolitan cities like Istanbul and Izmit (Kocaeli). Attempts have not been encouraging for the scattered
regional settlements using central storage sites due to financial shortages and received rejections from nearby settlements.
Small-scale compact solid waste management systems with materials recycling and composting can be more suitable alternatives
in the small-scale regional settlements. The major constituents of municipal solid waste are organic in nature and approximately
a quarter of municipal solid waste is recyclable. Although paper, including cardboard, is the main constituent, the composition
of recyclable waste varies strongly by the source or the type of collection point. Solid wastes need primary treatment in
order to be suitable for incineration and composting. Turkey needs to give more emphasis on the usage of modern solid waste
removal technologies to overcome the overgrowing solid waste disposal problems. 相似文献
996.
The circular economy has been developing rapidly in recent years in China. A legislative system has been created to provide
legal protection for the development of a circular economy, including a series of price and tax measures in the waste management
area. These measures form the basic foundation for promoting better waste management under the circular economic model. Many
challenges, however, remain. For instance, the legal system needs to incorporate more sophisticated science, and China lacks
key waste treatment technology that could support the further development of a circular economy. There is also a need to educate
the public about the concept of the circular economy and its benefits. Specific suggestions are made for the development and
implementation of the circular economic model. 相似文献
997.
Hisanori Watanabe Hidekichi Yoshino 《Journal of Material Cycles and Waste Management》2011,13(2):113-117
Since hydrogen is a renewable energy source, biohydrogen has been researched in recent years. However, data on hydrogen fermentation
by a leachate from a waste landfill as inoculum are scarce. We investigated hydrogen production using a leachate from an industrial
waste landfill in Kanagawa Prefecture. The results showed no methane gas production, and the leachate was a suitable inoculum
for hydrogen fermentation. The maximum H2 yield was 2.67 mol of H2 per mol of carbohydrate added, obtained at 30°C and an initial pH of 7. The acetate and butyrate production was significant
when the H2 yield was higher. Oxidation–reduction potential analysis of the culture suggested that hydrogen-producing bacteria in the
leachate were facultative anaerobic. Scanning electron microscope observations revealed that the hydrogen-producing bacteria
comprised bacilli about 2 μm in length. 相似文献
998.
Shinsuke Iijima Morito Nakamura Akira Yokoi Mitsuhiro Kubota Liwei Huang Hitoki Matsuda 《Journal of Material Cycles and Waste Management》2011,13(3):206-212
For an effective decomposition and removal of organic halogenated compounds, a packed-bed non-thermal plasma reactor with
in situ absorption of the resulting halogenated products by alkaline sorbent incorporated was proposed. In the plasma reactor,
α-Al2O3 particles of 1 and 3 mm (mean particle diameter) were packed as solid dielectric medium to enhance the plasma power density
in the reactor. Further, alkaline sorbent of Ca(OH)2 was doped onto the surface of α-Al2O3 particles, in order to remove halogenated products by in situ absorption with Ca(OH)2. A high-voltage and high-frequency pulsed power of −15 to 15 kV and 1 kHz was applied to the wire electrode of the plasma
reactor by means of a DC power source. In the present study, as the sample of an organic halogenated compound that is most
popularly used, we selected dichloromethane (CH2Cl2), and 500 ppm of the initial concentration of CH2Cl2 was fed into the reactor accompanied by air at a fixed flow rate of 500 × 10−6 m3 min−1 at room temperature. As a result, it was recognized that the amount of CH2Cl2 decomposed by non-thermal plasma in an α-Al2O3 particle bed increased with an increase in plasma input power. The ratio of decomposition of CH2Cl2 was almost 100% at 13 kV of electric power and 1 kHz frequency, and CO2, CH3Cl, COCl2, HCl, and Cl2 were observed as the major reaction products. On the other hand, when CH2Cl2 was introduced into the plasma reactor where α-Al2O3 particles doped with Ca(OH)2 were packed, the ratio of decomposition of CH2Cl2 became higher, compared to the case that α-Al2O3 particles were not doped with Ca(OH)2. Moreover, there were no halogenated by-product gases detected in the outlet gas from the reactor. As the solid reaction
products, CaClOH and Ca(ClO)2·4H2O were detected on Ca(OH)2 by X-ray diffraction. From these findings, it was recognized that CH2Cl2 was decomposed more effectively without producing unwanted harmful halogenated by-products in the proposed non-thermal plasma
reactor where α-Al2O3 particles doped with Ca(OH)2 sorbent were packed. 相似文献
999.
Waste incineration is becoming increasingly necessary to tackle the rapidly rising amounts of municipal solid waste (MSW);
in China many large cities are already surrounded by a girdle of landfills. Still, the not-in-my-backyard (nimby) syndrome
holds strong. This attitude stems from fear of dioxins. These have been associated with incineration (‘dioxin factories’)
and at times also with polyvinylchloride. In this paper this issue is analysed. China should build additional trust in MSW
incineration, following promulgation of stricter emission standards, enforced by stringent controls. 相似文献
1000.
Jung-Eun Lee 《Journal of Material Cycles and Waste Management》2011,13(3):259-263
Effective handling of municipal digested sludge requires that the product cake have low water content. To this end, we investigated
the change in sludge dewaterability after the addition of fly ash to municipal digested sludge, dewatering of which is difficult
because of its high organic content. The performance of the dewatering is compared with that of electroosmotic dewatering
(EDW) and conventional mechanical dewatering (CMD). Fly ash classified by sieving to the size of 25–75 μm and >75 μm is added
to the municipal digested sludge by 10, 20, and 50 wt% by wet base. When adding fly ash particles to municipal digested sludge,
dewatering efficiency improved with smaller fly ash particle size and with increase in the amount. When sludge was dewatered
using an electroosmotic dewatering method, the dewatering efficiency is improved about 40% by adding fly ash of 25–75 μm particle
size with 20 wt% when compared with conventional mechanical dewatering method without adding the fly ash. It is concluded
that fly ash particles rich in inorganic material are helpful in the dewatering process when added to municipal digested sludge
and EDW is more effective than CDW. 相似文献