全文获取类型
收费全文 | 9147篇 |
免费 | 691篇 |
国内免费 | 3044篇 |
专业分类
安全科学 | 879篇 |
废物处理 | 441篇 |
环保管理 | 802篇 |
综合类 | 5532篇 |
基础理论 | 1409篇 |
污染及防治 | 2463篇 |
评价与监测 | 479篇 |
社会与环境 | 455篇 |
灾害及防治 | 422篇 |
出版年
2024年 | 29篇 |
2023年 | 158篇 |
2022年 | 452篇 |
2021年 | 370篇 |
2020年 | 389篇 |
2019年 | 300篇 |
2018年 | 380篇 |
2017年 | 426篇 |
2016年 | 443篇 |
2015年 | 514篇 |
2014年 | 684篇 |
2013年 | 887篇 |
2012年 | 781篇 |
2011年 | 889篇 |
2010年 | 702篇 |
2009年 | 674篇 |
2008年 | 648篇 |
2007年 | 614篇 |
2006年 | 595篇 |
2005年 | 414篇 |
2004年 | 321篇 |
2003年 | 294篇 |
2002年 | 281篇 |
2001年 | 253篇 |
2000年 | 254篇 |
1999年 | 189篇 |
1998年 | 191篇 |
1997年 | 145篇 |
1996年 | 138篇 |
1995年 | 101篇 |
1994年 | 85篇 |
1993年 | 73篇 |
1992年 | 71篇 |
1991年 | 29篇 |
1990年 | 37篇 |
1989年 | 12篇 |
1988年 | 11篇 |
1987年 | 14篇 |
1986年 | 7篇 |
1985年 | 4篇 |
1984年 | 5篇 |
1983年 | 6篇 |
1982年 | 4篇 |
1981年 | 3篇 |
1979年 | 2篇 |
1978年 | 2篇 |
1977年 | 1篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
961.
962.
963.
964.
965.
复合型CoO/TiO2光催化剂降解亚甲基蓝动力学研究 总被引:1,自引:0,他引:1
以钛酸四丁酯为前驱体,采用溶胶凝胶法,制备了CoO掺杂的TiO2光催化剂。利用X射线衍射(XRD)、扫描电镜(SEM)、透射电镜(TEM)、紫外可见漫反射(UV-vis DRS)对催化剂进行了分析、表征。以中压汞灯为光源,研究了亚甲基蓝(MB)在CoO/TiO2微粒水悬浮液中的降解动力学。结果表明:所制备的催化剂活性组分主要是锐钛矿型的二氧化钛和CoO固溶体,粒径为25~30 nm,分布均匀。亚甲基蓝的光催化降解动力学满足一级动力学,在一定的浓度范围内,反应速率常数随初始浓度增大而减少,适当的掺钴量可以有效地提高TiO2光催化活性,其最佳掺杂量重量百分比为0.25%。 相似文献
966.
967.
pH、盐度对微生物还原硫酸盐的影响研究 总被引:2,自引:1,他引:1
采用厌氧生物处理工艺,研究了在不同盐度下pH连续降低对硫酸盐还原和有机物去除率的影响。实验结果表明,硫酸盐还原菌有很强的适应pH变化的能力,在pH值达到4以下仍有60%的硫酸盐去除率。NaCl浓度由4g/L增加到50g/L抑制了各厌氧菌的活性,导致硫酸盐和有机物去除率的下降,但硫酸盐还原菌耐受性高于产甲烷菌等其他厌氧菌,在NaCl浓度为50g/L下,硫酸盐去除率能达到50%,而有机物去除率则低于30%。qRT—PCR表明了系统菌落中SRB随着环境的变化情况与化学指标结果相一致,该反应器体系中SRB在整个厌氧菌群落中只占了很小部分。 相似文献
968.
Recycling of organic materials and solder from waste printed circuit boards by vacuum pyrolysis-centrifugation coupling technology 总被引:1,自引:0,他引:1
Here, we focused on the recycling of waste printed circuit boards (WPCBs) using vacuum pyrolysis-centrifugation coupling technology (VPCT) aiming to obtain valuable feedstock and resolve environmental pollution. The two types of WPCBs were pyrolysed at 600°C for 30 min under vacuum condition. During the pyrolysis process, the solder of WPCBs was separated and recovered when the temperature range was 400-600°C, and the rotating drum was rotated at 1000 rpm for 10 min. The type-A of WPCBs pyrolysed to form an average of 67.91 wt.% residue, 27.84 wt.% oil, and 4.25 wt.% gas; and pyrolysis of the type-B of WPCBs led to an average mass balance of 72.22 wt.% residue, 21.57 wt.% oil, and 6.21 wt.% gas. The GC-MS and FT-IR analyses showed that the two pyrolysis oils consisted mainly of phenols and substituted phenols. The pyrolysis oil can be used for fuel or chemical feedstock for further processing. The recovered solder can be recycled directly and it can also be a good resource of lead and tin for refining. The pyrolysis residues contained various metals, glass fibers and other inorganic materials, which could be recovered after further treatment. The pyrolysis gases consisted mainly of CO, CO(2), CH(4), and H(2), which could be collected and recycled. 相似文献
969.
A pilot program focusing on municipal solid waste (MSW) source-separated collection was launched in eight major cities throughout China in 2000. Detailed investigations were carried out and a comprehensive system was constructed to evaluate the effects of the eight-year implementation in those cities. This paper provides an overview of different methods of collection, transportation, and treatment of MSW in the eight cities; as well as making a comparative analysis of MSW source-separated collection in China. Information about the quantity and composition of MSW shows that the characteristics of MSW are similar, which are low calorific value, high moisture content and high proportion of organisms. Differences which exist among the eight cities in municipal solid waste management (MSWM) are presented in this paper. Only Beijing and Shanghai demonstrated a relatively effective result in the implementation of MSW source-separated collection. While the six remaining cities result in poor performance. Considering the current status of MSWM, source-separated collection should be a key priority. Thus, a wider range of cities should participate in this program instead of merely the eight pilot cities. It is evident that an integrated MSWM system is urgently needed. Kitchen waste and recyclables are encouraged to be separated at the source. Stakeholders involved play an important role in MSWM, thus their responsibilities should be clearly identified. Improvement in legislation, coordination mechanisms and public education are problematic issues that need to be addressed. 相似文献
970.
Li H Ye ZH Chan WF Chen XW Wu FY Wu SC Wong MH 《Environmental pollution (Barking, Essex : 1987)》2011,159(10):2537-2545
The effects of arbuscular mycorrhizal fungi (AMF) - Glomus intraradices and G. geosporum on arsenic (As) and phosphorus (P) uptake by lowland (Guangyinzhan) and upland rice (Handao 502) were investigated in soil, spiked with and without 60 mg As kg−1. In As-contaminated soil, Guangyinzhan inoculated with G. intraradices or Handao 502 inoculated with G. geosporum enhanced As tolerance, grain P content, grain yield. However, Guangyinzhan inoculated with G. geosporum or Handao 502 inoculated with G. intraradices decreased grain P content, grain yield and the molar ratio of grain P/As content, and increased the As concentration and the ratio of grain/straw As concentration. These results show that rice/AMF combinations had significant (p < 0.05) effects on grain As concentration, grain yield and grain P uptake. The variation in the transfer and uptake of As and P reflected strong functional diversity in AM (arbuscular mycorrhizal) symbioses. 相似文献