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排序方式: 共有1327条查询结果,搜索用时 812 毫秒
893.
应用金属离子在水溶液中同时水解平衡原理,对采用中和法净化煤矿酸性矿井水对去除Pb、Zn、Mn、Cu、Fe、Al等的最佳pH值和废水中的极限最低浓度进行了计算;对中和法净化酸性矿井水的操作提出了建议。 相似文献
894.
介绍了国外几种新机构压力机,可适应多变的工艺过程,通用性大,具有更高的柔性。其中机械驱动源的液压化、兼容机械压力机和液压机双方优点,体现了未来压力机的突出特征。 相似文献
895.
896.
缺氧及两级好氧处理岳阳化工总厂部分废水的运行与分析 总被引:1,自引:0,他引:1
介绍了岳阳化工总厂部分废水的处理工艺和设计,针对原水水质COD高等特点,采用缺氧,两级好氧工艺,该厂进生化池:COD浓度1000-14000mg/L,BOD3:COD=0.5左右;出生化池:COD浓度<120mg/L,低于GB8978-1996表4中石油化工工业规定的Ⅱ级排放标准,BOD3<10mg/L^ ,低于GB8978-1996表4石油化工工业规定的1级排放标准。 相似文献
897.
取自扬州某外资皮革厂的蓝皮制革废水含有大量的Cr^3+和COD。通过对该废水加各种碱剂调节其pH值至8.3~8.5,均可将Cr^3+去除90%以上,且对COD也有一定的去除效果。再对该废水加碱的同时试采用几种混凝剂进行混凝,Cr^3+和COD的去除率都得到提高。研究表明:通过加碱混凝能取得更好的去除效果,PAC/PAM是最佳混凝剂,最佳投药量为0.4g/L,Cr^3+可降到国家标准以下。 相似文献
898.
在分析图书馆文化和图书馆能力的基础上,说明了图书馆文化和图书馆能力的辩证关系,进而探讨了图书馆文化在图书馆能力建设中是原动力,是一种心理和思想协调,强调的是人的发展,因而,体现了图书馆文化在图书馆能力建设中的价值. 相似文献
899.
Gregory E Glass Timothy Shields Bin Cai Terry L Yates Robert Parmenter 《Ecological applications》2007,17(1):129-139
Interannual variation in the number of cases of human disease caused by hantaviruses in North America has been hypothesized to reflect environmental changes that influence rodent reservoir populations. This hypothesis postulates that when cases are rare reservoir populations are geographically restricted in patches of suitable habitat. Identifying these sites, which is needed to test the hypothesis, has proven to be a challenge. Satellite imagery of the U.S. Southwest has shown associations among the likelihood of human hantaviral disease and increases in the rodent populations, as well as increased prevalence of Sin Nombre virus (SNV) in rodent populations. In this study we characterize local areas that had environmental signatures that persisted as predicted highest risk sites for human disease through much of the 1990s. These areas represent a small percentage (0.3%) of the region. Exploratory analyses indicate that these areas were not randomly distributed, but were associated with certain landscape characteristics. Characteristics of elevation, slope, aspect, and land cover were associated with persistent high risk. Using multivariate Poisson regression to control for confounding effects, sites with deciduous- or mixed-forest land cover on moderate to steep slopes (>5 degrees) above 2130 m elevation were associated with increasing numbers of years at highest risk. These are candidate locations for refugia. Sites associated with cleared ground or shrubland were less often associated with high risk compared to reference conditions. The seasonal patterns of vegetation growth in persistently high-risk areas were compared to matched locations using MODIS (moderate resolution imaging spectroradiometer) NDVI (normalized difference vegetation index) during a time of a severe drought in the region from 2002 to 2004. Despite the drought and regardless of land cover, the NDVI in persistently highest risk areas had an early onset, with significantly higher levels of green vegetation that lasted longer than at comparable sites. These observations identify locations that can be monitored for the abundance of P. maniculatus and presence of SNV. If these sites are refugia, we predict they will be occupied by infected deer mice when other monitored sites are unoccupied. 相似文献
900.
Haiyan Xi Qiang Cai Miao He Hanchang Shi 《Frontiers of Environmental Science & Engineering》2007,1(3):381-384
This research describes a fast detection method on the basis of enzyme-linked immunosorbent assay (ELISA) for Escherichia coli in drainage of wastewater treatment plants. Optimized conditions such as the reaction format (sandwich or direct), the concentrations of diluted horseradish peroxidase (HRP)-E. coli conjugate, and anti-HPR antibody and pretreatment of E. coli were studied. Those results showed that the linear range of detection for E. coli was 10 cfu/mL-6 × 104 cfu/mL. Compared with conventional methods, it is a convenient and sensitive detection method with low cost. 相似文献