全文获取类型
收费全文 | 988篇 |
免费 | 54篇 |
国内免费 | 384篇 |
专业分类
安全科学 | 67篇 |
废物处理 | 62篇 |
环保管理 | 87篇 |
综合类 | 546篇 |
基础理论 | 209篇 |
污染及防治 | 309篇 |
评价与监测 | 30篇 |
社会与环境 | 35篇 |
灾害及防治 | 81篇 |
出版年
2023年 | 18篇 |
2022年 | 58篇 |
2021年 | 46篇 |
2020年 | 31篇 |
2019年 | 30篇 |
2018年 | 47篇 |
2017年 | 50篇 |
2016年 | 50篇 |
2015年 | 78篇 |
2014年 | 84篇 |
2013年 | 102篇 |
2012年 | 99篇 |
2011年 | 101篇 |
2010年 | 68篇 |
2009年 | 59篇 |
2008年 | 69篇 |
2007年 | 62篇 |
2006年 | 40篇 |
2005年 | 38篇 |
2004年 | 21篇 |
2003年 | 28篇 |
2002年 | 27篇 |
2001年 | 27篇 |
2000年 | 23篇 |
1999年 | 26篇 |
1998年 | 24篇 |
1997年 | 21篇 |
1996年 | 21篇 |
1995年 | 22篇 |
1994年 | 11篇 |
1993年 | 8篇 |
1992年 | 8篇 |
1991年 | 7篇 |
1990年 | 8篇 |
1989年 | 3篇 |
1988年 | 6篇 |
1987年 | 1篇 |
1986年 | 3篇 |
1985年 | 1篇 |
排序方式: 共有1426条查询结果,搜索用时 531 毫秒
731.
Dragun Z Raspor B Erk M Ivanković D Pavicić J 《Environmental monitoring and assessment》2006,114(1-3):49-64
The influence of the biometric parameters (shell mass, whole soft tissue mass, condition index) on MT and metal levels in the heat-treated cytosol of the whole soft tissue of transplanted mussels was studied over the period of one year. The positive correlation of three metals (Cd, Fe, Zn) with the shell mass indicated to time-dependent increase of their contents. Strong correlation of Mn content with the whole soft tissue mass (r = 0.74, p < 0.0001), and almost identical changes of these two parameters over the year make Mn a good indicator of mussel's condition. As opposed to the other metals, Cu content does not exhibit connection with biometry. On the other hand, MTs are highly influenced by biometry. As much as 65% of their variability could be explained by the changes of the shell mass and the whole soft tissue mass. Consequently, it is difficult to distinguish if the obtained positive correlation between Cd and MTs (r = 0.48, p < 0.05) reflects MT induction by Cd, or Cd accumulation as a result of age-dependent increase of MTs. Due to the strong influence of the biometry on MT level, the whole soft tissue is not considered as the best choice for measuring MTs as a biomarker. Better option would be to isolate a specific tissue that shows indisputable connection between MT induction and metal accumulation. 相似文献
732.
733.
对nano-SiO2与PAC复配使用强化混凝处理城市污水进行了实验研究.探讨了nano-SiO2在水中的分散效果、nano-SiO2强化混凝的工艺条件及强化效果.实验表明,与常规PAC强化混凝相比,nano-SiO2强化混凝能有效提高城市污水的除污效果、改善矾花沉降性能、缩短沉淀时间、提高城市污水化学絮凝强化一级处理工艺的抗冲击能力.同时投加nanoSiO2(25 mg/L)与PAC(75 mg/L)后,先快速搅拌(250r/min)2 min,然后慢速搅拌(60r/min)8 min,再沉淀3 min,出水COD、TP及浊度去除率分别为50.47%、79.84%和90.93%,较单独投加PAC(75 mg/L)分别提高28.43%、39.94%和62.18%. 相似文献
734.
Retrieval of total suspended matter (TSM) and chlorophyll-a (Chl-a) concentration from remote-sensing data for drinking water resources 总被引:1,自引:0,他引:1
Song K Li L Wang Z Liu D Zhang B Xu J Du J Li L Li S Wang Y 《Environmental monitoring and assessment》2012,184(3):1449-1470
The concentrations of chlorophyll-a (Chl-a) and total suspended matter (TSM) are major water quality parameters that can be retrieved using remotely sensed data. Water
sampling works were conducted on 15 July 2007 and 13 September 2008 concurrent with the Indian Remote-Sensing Satellite (IRS-P6)
overpass of the Shitoukoumen Reservoir. Both empirical regression and back-propagation artificial neural network (ANN) models
were established to estimate Chl-a and TSM concentration with both in situ and satellite-received radiances signals. It was found that empirical models performed
well on the TSM concentration estimation with better accuracy (R
2 = 0.94, 0.91) than their performance on Chl-a concentration (R
2 = 0.62, 0.75) with IRS-P6 imagery data, and the models accuracy marginally improved with in situ spectra data. Our results
indicated that the ANN model performed better for both Chl-a (R
2 = 0.91, 0.82) and TSM (R
2 = 0.98, 0.94) concentration estimation through in situ collected spectra; the same trend followed for IRS-P6 imagery data
(R
2 = 0.75 and 0.90 for Chl-a; R
2 = 0.97 and 0.95 for TSM). The relative root mean square errors (RMSEs) from the empirical model for TSM (Chl-a) were less than 15% (respectively 27.2%) with both in situ and IRS-P6 imagery data, while the RMSEs were less than 7.5% (respectively
18.4%) from the ANN model. Future work still needs to be undertaken to derive the dynamic characteristic of Shitoukoumen Reservoir
water quality with remotely sensed IRS-P6 or Landsat-TM data. The algorithms developed in this study will also need to be
tested and refined with more imagery data acquisitions combined with in situ spectra data. 相似文献
735.
Liang Zhang Chao Du Yun Du Meng Xu Shijian Chen Hongbin Liu 《Environmental monitoring and assessment》2015,187(6):381
Riparian wetlands provide critical functions for the improvement of surface water quality and storage of nutrients. Correspondingly, investigation of the adsorption characteristic and capacity of nutrients onto its sediments is benefit for utilizing and protecting the ecosystem services provided by riparian areas. The Langmuir and Freundlich isotherms and pseudo-second-order kinetic model were applied by using both linear least-squares and trial-and-error non-linear regression methods based on the batch experiments data. The results indicated that the transformations of non-linear isotherms to linear forms would affect the determination process significantly, but the non-linear regression method could prevent such errors. Non-linear Langmuir and Freundlich isotherms both fitted well with the phosphorus adsorption process (r 2?>?0.94). Moreover, the influences of temperature and ionic strength on the adsorption of phosphorus onto natural riparian wetland sediments were also studied. Higher temperatures were suitable for phosphorus uptake from aqueous solution using the present riparian wetland sediments. The adsorption capacity increased with the enhancement of ionic strength in agreement with the formation of inner-sphere complexes. The quick adsorption of phosphorus by the sediments mainly occurred within 10 min. The adsorption kinetic was well-fitted by pseudo-second-order kinetic model (r 2?>?0.99). The scanning electron microscopy (SEM) and Fourier transformation infrared (FT-IR) spectra analyses before and after phosphorus adsorption revealed the main adsorption mechanisms in the present system. 相似文献
736.
PRB技术对地下水中重金属离子的处理研究 总被引:3,自引:1,他引:2
实验模拟地下环境,以受重金属离子Pb(Ⅱ)、As(Ⅲ)、Cd(Ⅱ)、Cr(Ⅵ)、Fe(Ⅱ)和总Mn污染的地下水为研究对象,利用还原铁粉、铸铁粉、铸铁粉与颗粒活性炭的混合物为可渗透反应墙(PRB)的主要介质,石英砂为辅助介质,设计了3种反应器.在有效孔隙率为60%~65%、水力停留时间为12.0~14.4 h的条件下,考察其对污染物的去除效果.结果表明:3种反应器对Pb(Ⅱ)、As(Ⅲ)、Cd(Ⅱ)、Cr(Ⅵ)均有较高的去除效果,去除率达98%以上;总Mn的去除率分别达98%、89%和66%;Fe(Ⅱ)的去除率分别达83%、56%和49%.考察了3种反应器内pH、Eh、DO的关系及对重金属离子去除效果的影响,分析了污染物的去除机理.综合考虑处理效果与成本,笔者认为以铸铁粉与石英砂的混合物为PRB的反应介质,应用PRB技术原位处理受上述重金属离子污染的地下水是可行的. 相似文献
737.
738.
The effects of Ca2+on membrane fouling and trace organic compounds(TrOCs) removal in an electric field-assisted microfiltration system were investigated in the presence of Na+alone for comparison. In the electric field, negatively charged bovine serum albumin(BSA)migrated towards the anode far away from the membrane surface, resulting in a 42.9% transmembrane pressure(TMP) reduction in the presence of Na+at 1.5 V. In contrast, because of the stronger charge shielding of Ca2+ 相似文献
739.
740.