首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   653篇
  免费   52篇
  国内免费   257篇
安全科学   59篇
废物处理   26篇
环保管理   70篇
综合类   384篇
基础理论   119篇
污染及防治   212篇
评价与监测   30篇
社会与环境   23篇
灾害及防治   39篇
  2023年   7篇
  2022年   32篇
  2021年   26篇
  2020年   27篇
  2019年   18篇
  2018年   25篇
  2017年   34篇
  2016年   32篇
  2015年   38篇
  2014年   42篇
  2013年   73篇
  2012年   63篇
  2011年   60篇
  2010年   48篇
  2009年   37篇
  2008年   46篇
  2007年   46篇
  2006年   31篇
  2005年   18篇
  2004年   17篇
  2003年   23篇
  2002年   31篇
  2001年   21篇
  2000年   15篇
  1999年   24篇
  1998年   26篇
  1997年   26篇
  1996年   29篇
  1995年   19篇
  1994年   6篇
  1993年   5篇
  1992年   6篇
  1991年   4篇
  1988年   1篇
  1987年   1篇
  1986年   2篇
  1984年   2篇
  1982年   1篇
排序方式: 共有962条查询结果,搜索用时 31 毫秒
91.
电旋风除尘模型实验研究   总被引:9,自引:0,他引:9  
本研究试图将电除尘器与旋风除尘器组合为一体,以求取得较高的除尘效率,并利用旋转气流实现自动清灰。本文介绍了切向进气直流式电旋风除尘的模型试验,通过实测不同工况下的除尘效率和压力损失,应用经典除尘理论,建立了相应的数学模型。  相似文献   
92.
灾度指数及其意义   总被引:6,自引:5,他引:6  
孙卫东  彭子成 《灾害学》1995,10(2):16-20
本文分析了现行支度判别方法的不足,指出评价灾度时必须充分考虑承灾体对灾害的反应情况,并且根据判别准则的可比性原则,提出了灾度指数的概念,并以此做为灾度评价因子,旨在促进灾度评估工作的定量化、科学化,为防灾减灾服务。  相似文献   
93.
地面水中叶枯灵的高效液相色谱测定   总被引:2,自引:0,他引:2  
本文采用反相高效液相色谱法,在质控条件下,对河水,塘水两种地面水中叶枯灵的检验方法进行了测试,用Shimapck ODS柱为分析柱,以甲醇:水=50:50为流动相,并用冰醋酸调PH至4-5,紫外检测波长281nm,两种水样的平均回收率分别为91.7-96.3%,90-95.8%,相对标准偏差为4.3%,最低检出限为0.0261mg/l,为地面水中叶枯灵卫生标准的实施提供了简便,灵敏,正确的配套测试手段。  相似文献   
94.
采用向含氟废水中加入适量石灰和聚合氯化铝,然后投加适量钙盐、磷酸和聚丙烯酰胺的二级处理工艺除氟,通过控制合适的pH、钙盐和磷酸的投加量、反应时间、反应温度、搅拌强度和絮凝剂的投加量,可使黄磷废水中氟的质量浓度降至5mg/L,氟的去除率达到99%以上,出水中氟的质量浓度达到GB8978-1996一级排放标准。  相似文献   
95.
针对孤岛污水矿化度高,Cl-含量高,油含量和COD含量严重超标的现象,采取微生物接触氧化工艺进行外排采油污水治理的工艺研究。在处理过程中首先对菌种进行了严格的筛选和培养,然后在室内进行了模拟试验,最后在现场进行了中试。目前已根据中试结果,对孤岛污水原有的污水池进行了改造,设置了隔油池、气浮池、接触氧化池和沉淀池四个部分,经过一年的运行,成功地实现了污水的达标排放。  相似文献   
96.
减灾平衡点   总被引:1,自引:0,他引:1  
孙卫东 《灾害学》1993,8(4):92-93
文章依据经济学的原理提出了减灾平衡点的概念,并初步分析了它的特征及其实际意义。所谓减灾平衡点是指社会总体投资利益最大时减灾投资在社会总投资中所占的位置;此时,减灾投资利润率与社会正常生产投资利润率相当。  相似文献   
97.
Feng S  Kong Z  Wang X  Zhao L  Peng P 《Chemosphere》2004,56(5):457-463
Imidacloprid [1-(6-chloro-3-pyridylmethyl)-N-nitro-imidazolidin-2-ylideneamine] and RH-5849 [2'-benzoyl-l'-tert-butylbenzoylhydrazinel] are two pesticides used in China since 1992. In the present study we conducted acute toxicity test, micronucleus (MN) test and comet assay of the two pesticides on amphibian, Rana N. Hallowell, a sensitive organism suitable for acting as the bio-indicator of aquatic and agricultural ecosystems. The values of LC50-48 h of imidacloprid were found to be 165 mg l(-1) for tadpoles of Rana limnocharis and 219 mg l(-1) for tadpoles of Rana N. Hallowell. On the other hand, RH-5849 showed no acute toxicity to tadpoles during the 96 h exposure even it was saturated in the test solutions. There were significant differences in the MN frequencies between the negative controls and the treated groups at the dose of 8 mg l(-1) for imidacloprid (p < 0.05) and 40 mg l(-1) for RH-5849 (p < 0.01). Comet assay found significant differences (p < 0.01) in the distributions of DNA damage grades between the negative controls and groups treated in vitro with 0.05, 0.1, 0.2 and 0.5 mg l(-1) of imidacloprid and 5, 25, 50 and 100 mg l(-1) of RH-5849, respectively. DNA damage scores increased with the exposure levels of the two pesticides and dose-effect relationships were observed for both imidacloprid (r2 = 0.92) and RH-5849 (r2 = 0.98). The MN test and comet assay revealed potential adverse effects of the two pesticides on DNA in the erythrocytes of amphibians in aquatic and agricultural ecosystems.  相似文献   
98.
The incineration rate of municipal solid waste (MSW) has been increased because of difficulty in securing a proper disposal site for MSW in Korea. The advantage of incineration is reduction of the volume of waste; however, significant amounts of bottom ash and fly ash were generated in the incineration process. Their treatment has attracted growing interest because of the potential toxicity of hazardous heavy metals. Generally, heavy metals are less released from bottom ash than from fly ash. In this study the adsorption characteristics of heavy metals were investigated using various particle sizes of MSWI bottom ash. Since bottom ash has a broad particle size distribution, it was sieved to size classes of +20, -20, -48, -80, -100 mesh. Cation exchange capacity (CEC) was analyzed by the ammonium acetate method to evaluate the potential as an adsorbent. The CEC values and surface areas increase as the range of particle size becomes finer. The adsorption experiment was conducted using synthetic (Cu and Ni) and plating rinse water as a function of reaction time (10-180 min), liquid/solid ratio (2-100) and particle size (+20 to -100 mesh), respectively. The adsorption rate increased with decreasing particle size and with increasing liquid/solid ratio; however, the removal efficiency of Cu was higher than that of Ni. In the case of plating rinse water, the adsorption rate decreased sharply at high liquid/solid ratio, and it showed over 80% of adsorption rates for Cu and Ni at an initial pH of 3.  相似文献   
99.
Taihu Lake is the third largest freshwater lake in China. In recent years, the water pollution of cyanobacteria blooms has become a severe problem in this area. Microcystins (MCs) are an important group of toxic compounds mainly produced by some cyanobacteria species and have both acute and chronic hepatotoxic effects on animals and humans. This paper presents the first data on the identification and detection of MCs in both natural occurring cyanobacteria blooms and surface water samples (0-0.5 m), collected from Meiliang Bay, Taihu Lake, China. A conventional method for extraction and isolation of MCs from cyanobacteria blooms was applied. High-performance liquid chromatography (HPLC) analysis showed that the main toxic component in the cyanobacteria materials was MC-LR. The monoclonal antibody (mAb) against MC-LR produced by hybridoma technique was employed for direct competitive ELISA to detect the concentrations of MCs in bloom and water samples collected in 2001. The results not only revealed the presence of MCs but also temporal variations of MCs levels of three sampling stations in Meiliang Bay in 1 year. It is obvious that the MC contents were relatively higher during warm months and related with the status of eutrophication. Our study indicates the threat associated with MCs in water body of Taihu Lake. To prevent the MCs potential hazard on public health in this area, some necessary measures of monitoring and control of growth of cyanobacteria are urgently needed.  相似文献   
100.
纳氏试剂比色法测定氨氮的问题及修正   总被引:6,自引:0,他引:6  
预蒸馏—纳氏试剂比色法测定污水中氨氮实验中,硼酸与氢氧化钠用量影响有色胶体的稳定和测定的灵敏度,本文研究了影响规律,发现氢氧化钠有增敏作用,提出工作曲线应使用经过校正的标准曲线,校正曲线绘制及水样分析时,采用溶液中H3BO3含量为0.4%、MaOH含量为0.2mol/L显色溶液胶体稳定时间长达12小时以上,线性范围扩展为0~9mg/i,最低检出浓度为0.015mg/l  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号