全文获取类型
收费全文 | 1415篇 |
免费 | 63篇 |
国内免费 | 497篇 |
专业分类
安全科学 | 85篇 |
废物处理 | 87篇 |
环保管理 | 87篇 |
综合类 | 803篇 |
基础理论 | 234篇 |
污染及防治 | 500篇 |
评价与监测 | 64篇 |
社会与环境 | 55篇 |
灾害及防治 | 60篇 |
出版年
2024年 | 1篇 |
2023年 | 16篇 |
2022年 | 68篇 |
2021年 | 54篇 |
2020年 | 39篇 |
2019年 | 43篇 |
2018年 | 51篇 |
2017年 | 56篇 |
2016年 | 58篇 |
2015年 | 67篇 |
2014年 | 98篇 |
2013年 | 121篇 |
2012年 | 120篇 |
2011年 | 121篇 |
2010年 | 95篇 |
2009年 | 75篇 |
2008年 | 67篇 |
2007年 | 72篇 |
2006年 | 79篇 |
2005年 | 58篇 |
2004年 | 57篇 |
2003年 | 56篇 |
2002年 | 42篇 |
2001年 | 51篇 |
2000年 | 61篇 |
1999年 | 50篇 |
1998年 | 54篇 |
1997年 | 39篇 |
1996年 | 45篇 |
1995年 | 40篇 |
1994年 | 24篇 |
1993年 | 21篇 |
1992年 | 17篇 |
1991年 | 6篇 |
1990年 | 12篇 |
1989年 | 5篇 |
1988年 | 5篇 |
1987年 | 4篇 |
1986年 | 5篇 |
1985年 | 2篇 |
1984年 | 4篇 |
1983年 | 7篇 |
1982年 | 4篇 |
1981年 | 2篇 |
1980年 | 1篇 |
1978年 | 2篇 |
排序方式: 共有1975条查询结果,搜索用时 15 毫秒
131.
Xiaoming Li Tingting Shen Dongbo Wang Xiu Yue Xian Liu Qi Yang Jianbin Cao Wei Zheng Guangming Zeng 《环境科学学报(英文版)》2012,24(2):269-275
Three oxidation processes of UV-Fe3+(EDTA)/H2O2 (UV: ultraviolet light; EDTA: ethylenediaminetetraacetic acid), UV-Fe3+/H2O2 and Fe3+/H2O2 were simultaneously investigated for the degradation of amoxicillin at pH 7.0. The results indicated that, 100% amoxicillin degradation and 81.9% chemical oxygen demand (CODCr) removal could be achieved in the UV-Fe3+ (EDTA)/H2O2 process. The treatment efficiency of amoxicillin and CODCr removal were found to decrease to 59.0% and 43.0% in the UV-Fe3+/H2O2 process; 39.6% and 31.3% in the Fe3+/H2O2 process. Moreover, the results of biodegradability (biological oxygen demand (BOD5)/CODCr ratio) revealed that the UV-Fe3+ (EDTA)/H2O2 process was a promising strategy to degrade amoxicillin as the biodegradability of the effluent was improved to 0.45, compared with the cases of UV-Fe3+/H2O2 (0.25) and Fe3+/H2O2 (0.10) processes. Therefore, it could be deduced that EDTA and UV light performed synergetic catalytic effect on the Fe3+/H2O2 process, enhancing the treatment efficiency. The degradation mechanisms were also investigated via UV-Vis spectra, and high performance liquid chromatography-mass spectra. The degradation pathway of amoxicillin was further proposed. 相似文献
132.
133.
Pathogenic viruses in drinking water are great threats to public health. Visible-light-driven photocatalysis is a promising technology for virus inactivation. However, the existing photocatalytic antiviral research studies have mostly been carried out in single-component systems, neglecting the effect of natural organic matter, which exists widely in actual water bodies. In this paper, electrospun Cu-TiO2 nanofibers were prepared as photocatalysts, and their photocatalytic antiviral performance in the presence of humic acid (HA) was comprehensively studied for the first time. The properties of the reaction mixture were measured during the reaction. In addition, the safety, reliability and stability of photocatalytic disinfection in the mixed system were evaluated. The results showed that the virus removal efficiency decreased with the increase of the HA concentration. The type of reaction solution, such as PBS buffer solution or water, did not affect the removal efficiency noticeably. Under acidic conditions, the electrostatic forces between photocatalysts and viruses were strengthened, leading to higher virus removal efficiency. As the reaction time went on, the pH value in the solution increased first and then tended to be stable, the conductivity remained stable, and the dissolved oxygen increased first and then decreased. The safety test showed that the concentration of Cu ions released into the solution was lower than specified by the international standards. No photoreactivation was observed, and the addition of HA significantly reduced the reutilization efficiency of the photocatalysts. 相似文献
134.
135.
136.
137.
1 问题的提出 化学反应过程常常由于一些非预期的因素,如进料错误、杂质、反应器过热、冷却系统故障、外部火灾和搅拌失效等,使反应偏离正常操作范围,造成异常放热.若此时无法将所产生的热量迅速移除,则可能导致加速反应,形成自加速放热现象. 相似文献
138.
Shen H Virtanen HE Main KM Kaleva M Andersson AM Skakkebaek NE Toppari J Schramm KW 《Chemosphere》2006,62(3):390-395
The enantiomeric ratios (ER) of alpha-HCH and o,p'-DDT ((+)-isomer concentration/(-)-isomer concentration) and o,p'-DDD (first eluting enantiomer/second enantiomer) were investigated in 112 human placentas from Finnish boys collected 1997-2001. Both o,p'-DDD and alpha-HCH showed changes in their ER depending on the total concentration of the compound in the sample. Their ERs are approaching a value close to racemic mixture (ER=1) at high concentrations. At low concentrations they often differ from 1. The relationship between concentration and ER is clearly identified and it has been shown that it is not affected by analytical uncertainty. This relationship appears to be important for assessing tissue- and species-specific exposure and risk and it may indicate whether net uptake or metabolic activity is dominant in exposure for the resulting exposure of the enantiomers. 相似文献
139.
140.