全文获取类型
收费全文 | 901篇 |
免费 | 60篇 |
国内免费 | 271篇 |
专业分类
安全科学 | 67篇 |
废物处理 | 59篇 |
环保管理 | 69篇 |
综合类 | 474篇 |
基础理论 | 194篇 |
污染及防治 | 261篇 |
评价与监测 | 34篇 |
社会与环境 | 35篇 |
灾害及防治 | 39篇 |
出版年
2024年 | 1篇 |
2023年 | 19篇 |
2022年 | 47篇 |
2021年 | 34篇 |
2020年 | 31篇 |
2019年 | 35篇 |
2018年 | 34篇 |
2017年 | 41篇 |
2016年 | 39篇 |
2015年 | 42篇 |
2014年 | 69篇 |
2013年 | 77篇 |
2012年 | 71篇 |
2011年 | 64篇 |
2010年 | 54篇 |
2009年 | 59篇 |
2008年 | 41篇 |
2007年 | 50篇 |
2006年 | 34篇 |
2005年 | 33篇 |
2004年 | 31篇 |
2003年 | 34篇 |
2002年 | 39篇 |
2001年 | 24篇 |
2000年 | 32篇 |
1999年 | 32篇 |
1998年 | 41篇 |
1997年 | 23篇 |
1996年 | 18篇 |
1995年 | 22篇 |
1994年 | 13篇 |
1993年 | 6篇 |
1992年 | 8篇 |
1991年 | 9篇 |
1990年 | 6篇 |
1988年 | 2篇 |
1987年 | 1篇 |
1986年 | 4篇 |
1985年 | 2篇 |
1984年 | 2篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1981年 | 3篇 |
1977年 | 2篇 |
1969年 | 1篇 |
排序方式: 共有1232条查询结果,搜索用时 343 毫秒
301.
302.
谭培伦 《长江流域资源与环境》1999,8(3):320-326
在初步分析长江1998年水情与防汛情况的基础上,对长江防洪体系中各项措施的情况作了研究,说明在98年抗洪斗争中已建控制性水利枢纽发挥了较好的作用,如三峡工程已建成则防汛情势会有本质变化;长江主要堤防均保证了安全,出险多的是一些保护面积相对小的堤段;分蓄洪区安全建设严重滞后,从而难以决策实施计划分洪:“平垸行洪,退田还湖”应区别对待,植树造林,水土保持很严重,但不是影响98年洪水的主要因素。长江防洪 相似文献
303.
纳氏试剂光度法测定废水中氨氮的问题讨论 总被引:1,自引:0,他引:1
应用纳氏试剂比色法测定废水中的氨氮时,水样显色后稳定时间短,影响测定结果的准确性,针对这一问题进行了实验研究。实验中对主要影响因素I-和OH-的浓度变化进行了条件实验,结果表明选用所配的Ⅲ型纳氏试剂(KI含量为7.5g),可获得稳定的有色胶体,也可采用Ⅰ型纳氏试剂(KI含量为7.0g)、在中和硼酸后再多加2mLNaOH(1mol/L),也可获得稳定的有色胶体。 相似文献
304.
无论是工程措施还是非工程措施,它们对防御洪水、减轻灾害都是必须的。但是,任何手段都不可能制止洪水灾害,人类可以达到的目标只是减轻水灾损失,而各种减灾措施能够达到的实际效益决定于社会对它们的支持程度。作者研究了美国70年代以来防洪战略转移的历史进程,认为当此世纪之交,我国的防洪战略应更加注意政策导向,以增强国家防洪主管部门行使管理职权的权威性,并推动地方政府、社会各部门逐级分担防洪减灾责任。 相似文献
305.
应用大鼠全胚胎培养方法探讨偏钒酸铵的致畸作用及其机理 总被引:1,自引:0,他引:1
本文通过NH4VO3体外大鼠全胚胎培养致畸实验研究,发现NH4VO3对大鼠胚胎具有直接胚胎毒性和致畸性,且具有显的剂量一反应和时间一效应关系,其作用机理可能与卵黄囊的功能受到钒化物的损害有关。 相似文献
306.
The concentration of heavy metals in the bottom sediment and interstitial water collected from two reservoirs in Singapore was found to be enriched. A distribution coefficient,K d , was used to assess the chemical stability of heavy metals in the sediments. Numerical models were used to assess (1) the redistribution of heavy metals in a changing environment, and (2) long-term self clean-up capabilities of a reservoir. 相似文献
307.
PW Kok HY Ong MK Wong WK Au KT Tan WH Phoon CN Ong 《Environmental monitoring and assessment》1997,44(1-3):425-431
Occupational exposure to benzene was measured in two gasoline marketing terminals and five major refineries in Singapore. A total of 280 workers were monitored over two years. This assessment was carried out with two primary objectives: (1) To find out the extent of occupational exposure to benzene in the petroleum industry in Singapore, (2) To identify suitable biomarkers for monitoring of low levels of benzene exposure. The exposure was measured in five different categories of petroleum and petrochemical workers, i.e., truck drivers, despatch assistant, process operators, oil movements operators and laboratory technicians. The results revealed wide variations in exposure, from 0.01 to 13.6 ppm for personal time weighted average (TWA) exposure over the whole workshift. The exposure of truck drivers appeared to be the highest, with geometric mean (GM) of 1.98 ppm (ranged from 0.25 to 13.6 ppm). The average benzene exposure for process operators was relative low with a GM of 0.04 ppm. Lowest benzene exposure was found in the laboratory technicians, with a GM of 0.02 ppm. As cigarette smoking is known to affect metabolism of benzene, data analyses on the relationships with environmental exposure were conducted only on the 190 nonsmokers. The results showed that urinary trans, trans-muconic acid (ttMA), unmetabolized benzene in urine (UBZ) and benzene in blood (BBZ) were better biomarkers for low level benzene exposure as compared to urinary phenolic metabolites in urine, such as hydroquinone, phenol and catechol. 相似文献
308.
A tripartite participation of government, trade unions and university was formed in 1988 to study the situation of industrial noise and hearing acuity of workers. Since 1982, the six industries identified by the Noise Control Office were construction, electronics, metals, plastics, shipbuilding and repairing, and textiles. Safety-subcommittees were formed. With the help of these subcommittees, 21 out of 32 medium-size factories responded to the study. A total of 922 sound measurements were made and 1062 out of 10724 workers were examined. More than one third (37.5%) of workers worked in locations with noise level in excess of L
eq (8h) 90 dBA. Among examined subjects, 39.8% were exposed to L
eq (8) 90 dBA and above and 18.6% were found to have industrial hearing loss. Multiple logistic regression analyses adjusted for sex and age showed that for hearing loss, the important risk factors were duration of occupational noise exposure, noise intensity, floor vibration and military experience. Current legislation and measures in hearing conservation were inadequate despite the implementation of inspection by the Noise Control Office. Recommendations were directed at amending relevant legislation, increasing supervision of use of personal ear protection, and strengthening health education and audiometric surveillance of exposed workers. 相似文献
309.
Proper control of the activated sludge process is essential in ensuring production of good effluent. COD adsorption capacity (CAC) of the activated sludge could be used as a control parameter. CAC is determined by mixing the activated sludge with the settled sewage and measuring the instantaneous COD reduction per unit mass of activated sludge. CAC measures substrate removal by physical adsorption and reflects the quality of the activated sludge. CAC of a healthy activated sludge increases with the flow along the aeration units. CAC could be used for process decision on variation in air supply and feed pattern to the aeration units. In a modified process to cope with sludge bulking problem, CAC could be used to estimate the air supply to the aeration unit which is merely used for reaerating the returned sludge. 相似文献
310.
重金属铅,镉,锌对小麦DNA构象的影响 总被引:1,自引:0,他引:1
采用紫外吸收谱法,研究了不同浓度铅,镉,锌对小麦DNA构象的影响。结果显示重金属铅,镉,锌均可影响小麦DNA构象,使其紫外吸收峰值发生变化。其中,铅离子对小麦DNA构象影响最大,50μg/ml^pb^2+处理使小麦出现明显减色反应,1000μg/mlpb^2+处理使其沉淀析出;镉离子对小麦DNA构象影响不大,可使其产生轻微减色反应,低浓度锌离子使小麦DNA发生增色反应,而高浓度使小麦DNA发生减色 相似文献