全文获取类型
收费全文 | 40446篇 |
免费 | 406篇 |
国内免费 | 373篇 |
专业分类
安全科学 | 1282篇 |
废物处理 | 1882篇 |
环保管理 | 5122篇 |
综合类 | 7010篇 |
基础理论 | 10262篇 |
环境理论 | 13篇 |
污染及防治 | 9950篇 |
评价与监测 | 2902篇 |
社会与环境 | 2559篇 |
灾害及防治 | 243篇 |
出版年
2022年 | 371篇 |
2021年 | 401篇 |
2020年 | 249篇 |
2019年 | 325篇 |
2018年 | 573篇 |
2017年 | 612篇 |
2016年 | 948篇 |
2015年 | 705篇 |
2014年 | 1125篇 |
2013年 | 3232篇 |
2012年 | 1357篇 |
2011年 | 1776篇 |
2010年 | 1438篇 |
2009年 | 1526篇 |
2008年 | 1800篇 |
2007年 | 1736篇 |
2006年 | 1571篇 |
2005年 | 1414篇 |
2004年 | 1352篇 |
2003年 | 1320篇 |
2002年 | 1237篇 |
2001年 | 1513篇 |
2000年 | 1026篇 |
1999年 | 671篇 |
1998年 | 467篇 |
1997年 | 509篇 |
1996年 | 530篇 |
1995年 | 595篇 |
1994年 | 533篇 |
1993年 | 444篇 |
1992年 | 493篇 |
1991年 | 479篇 |
1990年 | 456篇 |
1989年 | 430篇 |
1988年 | 413篇 |
1987年 | 319篇 |
1986年 | 335篇 |
1985年 | 353篇 |
1984年 | 360篇 |
1983年 | 344篇 |
1982年 | 362篇 |
1981年 | 320篇 |
1980年 | 238篇 |
1979年 | 269篇 |
1978年 | 248篇 |
1977年 | 203篇 |
1975年 | 204篇 |
1974年 | 218篇 |
1973年 | 237篇 |
1972年 | 214篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
161.
162.
163.
164.
165.
Photoactive aluminum doped ZnO(AlZnO) was synthesized by sol-gel method.After that,AlZnO photocatalyst was deposited on five carbon-based materials(CBMs) using ultrasonic route followed by solid-state mixing using ball mill.The CBMs used were poly aniline(PANI),carbon nitride(CN),carbon nanotubes(CNT),graphene(G),and carbon nanofibers(CNF).The crystal phases,elemental compositions,morphological,and optical properties of the AlZnO@CBMs composites were investigated.Experimental results revealed that two of AlZnO@CBMs composites exhibited superior bleaching efficiency(100% removal) and photocatalytic stability(three cycles) for 50 μmol/L Methylene Blue(MB) contaminated water after 60 min irradiation in visible light at pH 6.5,0.7% H_2O_2,and 5 g/L inorganic salts.Under optimum conditions,AlZnO@CBMs nanocomposites were employed for the treatment of mixed dyestuffs composed of MB,Methyl Orange(MO),Astrazone Blue FRR(BB 69),and Rhodamine B(RhB) dyes under dark,ultraviolet,visible,and direct sunlight.For mixed dyestuffs,the AlZnO@G achieved the highest dye sorption capacity(60.91 μmol dye stuffs/g) with kinetic rate 8.22 × 10~(-3) min~(-1) in 90 min via multi-layer physisorption(Freundlich isotherm) on graphene sheet.In additions,AlZnO@CN offered the highest photo-kinetic rate(K_(photo)) of~54.1 × 10~(-3) min~(-1)(93.8% after 60 min) under direct sunlight.Furthermore,the selective radical trapping experiment confirmed that the holes and oxidative superoxide radicals are crucial on dyes photodegradation pathway.Owing to their superior performance,AlZnO@G and AlZnO@CN nanocomposites can offer an effective in-situ solar-assisted adsorption/photocatalytic remediation of textile wastewater effluents. 相似文献
166.
Advanced oxidation technologies are a friendly environmental approach for the remediation of industrial wastewaters. Here, one pot synthesis of mesoporous WO_3 and WO_3-graphene oxide(GO) nanocomposites has been performed through the sol–gel method. Then, platinum(Pt) nanoparticles were deposited onto the WO_3 and WO_3-GO nanocomposite through photochemical reduction to produce mesoporous Pt/WO_3 and Pt/WO_3-GO nanocomposites. X-ray diffraction(XRD) findings exhibit a formation of monoclinic and triclinic WO_3 phases. Transmission Electron Microscope(TEM) images of Pt/WO_3-GO nanocomposites exhibited that WO_3 nanoparticles are obviously agglomerated and the particle sizes of Pt and WO_3 are ~ 10 nm and 20–50 nm, respectively. The mesoporous Pt/WO_3 and Pt/WO_3-GO nanocomposites were assessed for photocatalytic degradation of Methylene Blue(MB) as a probe molecule under visible light illumination.The findings showed that mesoporous Pt/WO_3, WO_3-GO and Pt/WO_3-GO nanocomposites exhibited much higher photocatalytic efficiencies than the pure WO_3. The photodegradation rates by mesoporous Pt/WO_3-GO nanocomposites are 3, 2 and 1.15 times greater than those by mesoporous WO_3, WO_3-GO, and Pt/WO_3, respectively. The key factors of the enhanced photocatalytic performance of Pt/WO_3-GO nanocomposites could be explained by the highly freedom electron transfer through the synergetic effect between WO_3 and GO sheets, in addition to the Pt nanoparticles that act as active sites for O2 reduction, which suppresses the electron hole pair recombination in the Pt/WO_3-GO nanocomposites. 相似文献
167.
168.
169.
170.