全文获取类型
收费全文 | 1291篇 |
免费 | 98篇 |
国内免费 | 482篇 |
专业分类
安全科学 | 100篇 |
废物处理 | 57篇 |
环保管理 | 90篇 |
综合类 | 842篇 |
基础理论 | 231篇 |
污染及防治 | 334篇 |
评价与监测 | 89篇 |
社会与环境 | 93篇 |
灾害及防治 | 35篇 |
出版年
2024年 | 3篇 |
2023年 | 34篇 |
2022年 | 102篇 |
2021年 | 89篇 |
2020年 | 88篇 |
2019年 | 83篇 |
2018年 | 82篇 |
2017年 | 80篇 |
2016年 | 64篇 |
2015年 | 91篇 |
2014年 | 137篇 |
2013年 | 135篇 |
2012年 | 111篇 |
2011年 | 98篇 |
2010年 | 77篇 |
2009年 | 62篇 |
2008年 | 68篇 |
2007年 | 60篇 |
2006年 | 49篇 |
2005年 | 40篇 |
2004年 | 27篇 |
2003年 | 37篇 |
2002年 | 46篇 |
2001年 | 43篇 |
2000年 | 15篇 |
1999年 | 27篇 |
1998年 | 16篇 |
1997年 | 16篇 |
1996年 | 20篇 |
1995年 | 11篇 |
1994年 | 9篇 |
1993年 | 11篇 |
1992年 | 11篇 |
1991年 | 8篇 |
1990年 | 2篇 |
1989年 | 7篇 |
1988年 | 7篇 |
1986年 | 3篇 |
1982年 | 1篇 |
1981年 | 1篇 |
排序方式: 共有1871条查询结果,搜索用时 990 毫秒
991.
992.
993.
针对单层多孔隙沥青路面容易阻塞的问题,提出双层多孔隙沥青路面结构形式,采用有限元的方法,应用空气介质和吸声结构的声一固耦合模型,通过大型商用软件ABAQUS对多孔隙沥青路面吸声结构的吸声性能进行数值仿真模拟,分析了双层多孔隙沥青路面中空隙率组合以及厚度组合下的降噪特性,据此提出适宜的双层多孔隙沥青路面结构参数,计算结果表明双层多孔隙沥青路面结构,当上层空隙率为10%,下层空隙率为25%,上层厚度为2cm,下层厚度为4cm时,吸声效果较好。结论可为双层多孔隙沥青路面的应用提供理论基础。 相似文献
994.
Residues and chiral signatures of organochlorine pesticides in sediments from Xiangshan Bay, East China Sea 总被引:1,自引:0,他引:1
Yang YH Zhou SS Li YY Xue B Liu T 《Journal of environmental science and health. Part. B》2011,46(2):105-111
Residual levels and enantiomeric signatures of hexachlorocyclohexanes (HCHs) and dichlorodiphenyltrichloroethanes (DDTs) in surface sediments from Xiangshan Bay, East China Sea were investigated. The concentrations of ∑HCHs (sums of α-, β-, γ-, and δ-HCH) and ∑DDTs (sums of p, p'-DDT, p, p'-DDD,p, p'-DDE, o, p'-DDT, and o, p'-DDD) ranged from 0.14 to 0.67 ng g?1 and 0.61 to 22.38 ng g?1, respectively. A slight potential health risk to the organism was then indicated for the residual levels of DDTs according to the ERL/ERM guidelines. Moreover, the predominant β-HCH implied that the technical HCH contamination was mainly due to the historical usage. But the high ratio of DDT/∑DDTs depicted a cocktail input pattern of fresh and weathered DDTs. The enantiomeric fractions (EFs) of α-HCH, o, p'-DDT, and o, p'-DDD were also determined. The degradation of α-HCH was enantioselective in all sediments samples, resulting in an enrichment of (-)-enantiomers. However, the racemic residues of o, p'-DDT and o, p'-DDD were observed in all sediments samples. 相似文献
995.
Performance and characteristics of biosorption of Pb(II) had been studied in a batch system using the fungal strain biomass, KC-2. The biosorption performance was investigated by analysing the effects of such factors as the initial pH, initial Pb(II) concentration, and contact time at 303 K. The maximum Pb(II) adsorption was obtained at pH 5.0. The experimental data were described by the pseudo first-order, pseudo second-order and intraparticle diffusion kinetic models, and were closely followed the pseudo second-order kinetic model. The equilibrium experimental data were well fitted to Langmuir model and the maximum biosorption capacity was 84.03 mg g(-1). The adsorption mechanism was examined by FTIR, SEM and EDAX analysis. Results indicated that carboxylic, hydroxyl and amine groups were involved in the biosorption and ion exchange mechanism existed. 相似文献
996.
中国癌症与土壤环境中铊元素的关系 总被引:4,自引:0,他引:4
利用土壤环境中铊元素资料769个数据,癌死亡调查资料787080例,研究了胃癌,食管癌,肝癌,宫颈癌,肺癌、大肠癌、白血病、鼻咽癌、乳腺癌死亡率与人群生存区土壤环境中铊元素的关系。 相似文献
997.
Jian-Ping Guo Xiao-Ye Zhang Hui-Zheng Che Sun-Ling Gong Xingqin An Chun-Xiang Cao Jie Guang Hao Zhang Ya-Qiang Wang Xiao-Chun Zhang Min Xue Xiao-Wen Li 《Atmospheric environment (Oxford, England : 1994)》2009,43(37):5876-5886
Using one year of Aerosol Optical Depth (AOD) derived from Moderate Resolution Imaging Spectroradiometer (MODIS) on the Terra satellite and particular matter (PM) contents measured at eleven sites located mostly in the eastern China in 2007, the relationship between columnar AOD and hourly and daily average (DA) PM were established. The peak AOD observed from MODIS was generally consistent with the surface PM measurements in eastern China, where Zhengzhou had the maximum annual mean PM10 of 182.1 μg m?3, while Longfengshan had the minimum annual mean of 38.1 μg m?3. Ground level observations indicated that PM concentration varies widely across different regions, which was mainly due to the difference in weather conditions and anthropogenic emissions. The coarse particles accounted for the main air pollution in Zhengzhou and Benxi whiles the fine particles, however, were the main constituents in other sites. Results showed that MODIS AOD (averaged over the box of 5 × 5 and 3 × 3 pixels) had a better positive correlation with the coincident hourly average (HA) PM concentration than with DA due to diurnal variation in PM mass measurements. After correcting AOD for relative humidity (RH), the correlation did not improve significantly, suggesting that the RH was not the main factor affecting the correlation of PM with AOD. The statistical regression analysis between MODIS AOD and PM mass suggested that the satellite-derived AOD is a useful tool for mapping PM distribution over large spatial domains. 相似文献
998.
栏目按语:随着国家经济实力的提升和"以人为本"科学理念的贯彻,我国劳动者的职业安全与健康水平正在得到不断改善,这其中包含着中国个体防护装备产业同仁们的努力与奉献. 相似文献
999.
以钛酸四丁酯为原料,空心微珠为载体,采用溶胶-凝胶法制备TiO2/beads光催化剂载体,然后浸渍法制备出H4SiW12O40/TiO2/beads表面负载修饰型复合光催化剂,并运用SEM、XRD、FT-IR和DRS对催化剂进行表征和分析.研究了H4SiW12O40/TiO2/beads对亚甲基蓝降解的光催化活性,考察了光强度、pH值、曝气量、底物浓度和催化剂用量等对催化效率的影响.实验结果表明,在中性条件下,H4SiW12O40/TiO2/beads催化剂的投加量为0.25 g/L,浓度为7.5 mg/L的亚甲基蓝溶液在250 W的紫外灯和600 W的可见光灯下光照60 min降解率分别可达到94.5%和55%. 相似文献
1000.
Trusting relationships are increasingly considered vital for making teams productive. We propose that cooperative management of conflict can help team members to be convinced that their teammates are trustworthy. Results from 102 organizations in China support the theorizing that how teams to manage conflict with each other affects within‐team conflict management. Specifically, cooperative conflict between teams helps teams to manage their internal conflicts cooperatively that strengthens trust that in turn facilitates team performance. Results provide support for managing conflict cooperatively as a foundation for trusting, productive relationships in China as well as in the West. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献