全文获取类型
收费全文 | 6278篇 |
免费 | 536篇 |
国内免费 | 2011篇 |
专业分类
安全科学 | 518篇 |
废物处理 | 286篇 |
环保管理 | 483篇 |
综合类 | 3911篇 |
基础理论 | 1018篇 |
环境理论 | 1篇 |
污染及防治 | 1488篇 |
评价与监测 | 386篇 |
社会与环境 | 533篇 |
灾害及防治 | 201篇 |
出版年
2024年 | 27篇 |
2023年 | 144篇 |
2022年 | 388篇 |
2021年 | 379篇 |
2020年 | 384篇 |
2019年 | 293篇 |
2018年 | 293篇 |
2017年 | 354篇 |
2016年 | 343篇 |
2015年 | 400篇 |
2014年 | 479篇 |
2013年 | 565篇 |
2012年 | 525篇 |
2011年 | 521篇 |
2010年 | 422篇 |
2009年 | 399篇 |
2008年 | 434篇 |
2007年 | 317篇 |
2006年 | 345篇 |
2005年 | 228篇 |
2004年 | 196篇 |
2003年 | 212篇 |
2002年 | 201篇 |
2001年 | 157篇 |
2000年 | 167篇 |
1999年 | 107篇 |
1998年 | 107篇 |
1997年 | 80篇 |
1996年 | 71篇 |
1995年 | 48篇 |
1994年 | 51篇 |
1993年 | 45篇 |
1992年 | 37篇 |
1991年 | 20篇 |
1990年 | 18篇 |
1989年 | 12篇 |
1988年 | 13篇 |
1986年 | 8篇 |
1984年 | 5篇 |
1983年 | 2篇 |
1982年 | 8篇 |
1981年 | 2篇 |
1978年 | 6篇 |
1977年 | 1篇 |
1975年 | 1篇 |
1974年 | 1篇 |
1973年 | 1篇 |
1972年 | 3篇 |
1971年 | 2篇 |
1970年 | 1篇 |
排序方式: 共有8825条查询结果,搜索用时 31 毫秒
321.
以模拟印染废水和实际印染废水为实验对象,检验了一种新合成有机-无机复合絮凝剂(PST)的絮凝效果。结果表明,PST具有良好的絮凝性能。在受试条件下,絮凝效果与絮凝剂投加量、染料浓度有较大相关性。废水的pH值应用范围较宽;搅拌时间对COD去除率和脱色率没有显著影响。采用PST处理广东省高明市某印染厂的印染废水后,COD去除率为75.16%,脱色率为76.18%,处理效果良好,处理成本明显低于目前市场上普遍使用的聚铝等絮凝剂。 相似文献
322.
Odorous compounds in the influent of a reclaimed water treatment plant (RWTP), consisting of coagulation, sedimentation, continuous micro-filtration (CMF), and chlorination in succession, in a north China city, were identified by combining flavor profile analysis (FPA) with sensory gas chromatograph-mass spectrometry (GC-MS). The sewery/swampy/septic odor with an odor intensity of 6.4 was found to be the major odor group in the RWTP influent, and the existence of well-known odorant including dimethyl disulfide, dimethyl trisulfide, indole and skatole were confirmed using GC-MS. The result of a spiking test showed that the intensity (3.6) of the sewery/swampy/septic odor caused by these four chemicals contributed to over 50% of the odor intensity of the influent. The FPA intensity for sewery/swampy/septic odor in the RWTP effluent was 3.8, showing that the treatment process was not efficient for the removal of odorants, particularly indole and skatole. 相似文献
323.
The activities of CeO2 nanocubes calcined at different temperatures were tested for catalytic oxidation of o-xylene. Using CeO2 nanocubes as catalysts, complete catalytic oxidation of o-xylene was achieved below 210℃. The CeO2 nanomaterials were characterized by means of BET, X-ray diffraction (XRD), transmission electron microscopy (TEM), and high-resolution transmission electron microscopy (HRTEM). From the TEM images, all Ce02 nanocubes displayed cubic morphology irrespective of calcination temperature. The HRTEM images revealed that these nanocubes were enclosed by reactive {001}planes, which may contribute to the intrinsically catalytic property of o-xylene oxidation. The higher activity of Ce02 nanocubes calcined at 550℃ than those calcined at above 550℃ was attributed to their smaller crystallite size and larger surface area. The influences of reaction conditions were also studied, which found that a higher reaction temperature was necessary for complete catalytic oxidation of o-xylene at higher weight hourly space velocity (WHSV) and o-xylene concentration. 相似文献
324.
Electromagnetic (EM) wave pollution has become the chief physical pollution for environment. The core-nanoshell composite absorbers with magnetic fly-ash hollow cenosphere as core and nanocrystalline magnetic material as shell were prepared by high-energy ball milling. The results of X-ray diffraction analysis (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM) and vector network analyzer (VNA) analysis indicated that perfect-crystalline nanomagnetic material coating was gotten with a particle size of 12 nm, being dried at 60°C for 2 hr and calcined at 400°C for 1 hr after ball milling. The exchange-coupling interaction happened between ferrite of cenosphere and soft magnet γ-Fe203 coating, it enhances magnetic loss of composite absorbers. In the frequency between 1 MHz and 1 GHz, the absorbing effectiveness of the core-nanoshell composite absorbers can achieve ?30 dB, it is better than single material and is consistent with requirements of the microwave absorbing material at the low-frequency absorption. 相似文献
325.
326.
为了了解过氧化氢与三维电极的协同作用,以罗丹明B模拟废水进行了实验研究,探索了填料配比、外加电压、过氧化氢投加量、初始废水pH值、染料初始浓度等单因子对降解罗丹明B的影响,并通过正交试验研究各因素对该法处理罗丹明B模拟废水的效应.结果表明,过氧化氢与三维电极在处理罗丹明B模拟废水时具有明显的协同作用;外加电压=20v,... 相似文献
327.
328.
329.
330.