全文获取类型
收费全文 | 2238篇 |
免费 | 17篇 |
国内免费 | 91篇 |
专业分类
安全科学 | 105篇 |
废物处理 | 210篇 |
环保管理 | 280篇 |
综合类 | 293篇 |
基础理论 | 392篇 |
环境理论 | 1篇 |
污染及防治 | 783篇 |
评价与监测 | 193篇 |
社会与环境 | 74篇 |
灾害及防治 | 15篇 |
出版年
2023年 | 11篇 |
2022年 | 33篇 |
2021年 | 36篇 |
2020年 | 12篇 |
2019年 | 41篇 |
2018年 | 70篇 |
2017年 | 58篇 |
2016年 | 78篇 |
2015年 | 54篇 |
2014年 | 67篇 |
2013年 | 178篇 |
2012年 | 123篇 |
2011年 | 143篇 |
2010年 | 96篇 |
2009年 | 129篇 |
2008年 | 134篇 |
2007年 | 144篇 |
2006年 | 128篇 |
2005年 | 114篇 |
2004年 | 105篇 |
2003年 | 97篇 |
2002年 | 88篇 |
2001年 | 62篇 |
2000年 | 35篇 |
1999年 | 24篇 |
1998年 | 20篇 |
1997年 | 23篇 |
1996年 | 16篇 |
1995年 | 18篇 |
1994年 | 18篇 |
1993年 | 19篇 |
1992年 | 10篇 |
1991年 | 19篇 |
1990年 | 10篇 |
1989年 | 9篇 |
1988年 | 10篇 |
1986年 | 7篇 |
1985年 | 8篇 |
1984年 | 7篇 |
1983年 | 7篇 |
1982年 | 10篇 |
1981年 | 10篇 |
1980年 | 9篇 |
1978年 | 6篇 |
1976年 | 5篇 |
1974年 | 4篇 |
1973年 | 5篇 |
1972年 | 6篇 |
1971年 | 6篇 |
1969年 | 5篇 |
排序方式: 共有2346条查询结果,搜索用时 31 毫秒
761.
Borgmann U Grapentine L Norwood WP Bird G Dixon DG Lindeman D 《Chemosphere》2005,61(11):1740-3; author reply 1744-5
762.
In this experiment, Bacillus insolitus was isolated and selected from a mixed culture that have been acclimated to chlorophenols. Decomposition of chlorophenolic compounds will be studied using this pure culture in both suspended and immobilized form. The results are: at lower initial concentrations of 2,4-dichlorophenol (10-50 mg/l), immobilized Bacillus insolitus shows a higher removal of 2,4-dichlorophenol than Bacillus insolitus in suspended growth. When the 2,4-dichlorophenol concentration becomes higher (50-200 mg/l), both immobilized and suspended Bacillus insolitus have approximately the same efficiency for removal of 2,4-dichlorophenol. Higher concentrations of 2,4-dichlorophenol are inhibitive to the growth of either suspended or immobilized Bacillus insolitus. At lower concentrations of 2,4-dichlorophenol, immobilized mixed culture may have the same removal efficiency of 2,4-dichlorophenol as immobilized pure culture of Bacillus insolitus. But with regard to the overall 2,4-dichlorophenol removal efficiency, immobilized pure culture is considered to be superior to immobilized mixed culture. 相似文献
763.
The formation of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDDs/Fs) from carbon that was produced by the pyrolysis of paper fibers and from
wood charcoal was investigated experimentally. Fibers obtained from filter paper were pyrolyzed at 300° and 800°C to produce
low- and high-temperature carbon samples. The two types of carbon and wood charcoal were mixed with silica (SiO2) and trace copper oxide to produce three synthetic fly ash samples. Experiments to measure the formation of PCCDs/Fs from
the three ash samples were conducted using a bench-scale reactor. The two carbon samples derived from paper fibers generated
more PCDDs/Fs than was generated by the wood charcoal. The PCDDs/Fs generated by the low-temperature carbon and by the wood
charcoal were dominated by the lower-chlorinated PCDFs. Such unique homologue distribution patterns are very similar to those
generated by the open burning of household waste. The high-temperature carbon generated more highly chlorinated PCDDs/Fs.
The effect of pyrolysis temperature on the de novo formation of PCDDs/Fs from residual carbon is discussed. Paper and paper
products contained in household waste are likely to be the source of unburned carbon that contributes to high PCDD/F emissions
in the open burning of household waste. 相似文献
764.
Shigehisa Endoh Kenzo Takahashi Jae-Ryeong Lee Hitoshi Ohya 《Journal of Material Cycles and Waste Management》2006,8(1):88-94
Enforcement of the Automobile Recycling Law in Japan requires utilization of automobile shredder residue (ASR). However, the
high contents of copper (∼5%) and chlorine (∼1%) in ASR stand in the way of practical application. We studied methods for
the removal of copper and chlorine from ASR so that it could be utilized as a fuel. By compression of the ASR for solidification
with an extruder, the polyvinylchloride (PVC) that covered electrical cables was softened and stripped from the copper wire.
The solidified ASR was comminuted with cutter mills and classified by dry density separation. The copper content of the obtained
light products was 0.2%–0.5%. Furthermore, we studied the possibility of dechlorination of the ASR by mechanochemical (MC)
activation. The light product of the ASR was milled with CaO or CaCO3. The chlorine content decreased to about one-tenth of the original value after MC activation over 8 h. Therefore, the combined
processing of softening–stripping and comminution liberated the PVC-covered cables and decreased the copper content of the
ASR. In addition, dechlorination of the ASR was also possible by MC activation with the addition of calcium compounds. 相似文献
765.
In this study, we examined the role of organizational level as a moderator of the relationships of procedural and distributive justice with seven employee attitudes and behaviors. Based on social identity and resource allocation theories, we suggested an allocational model of authority in organizations. We posited that lower rank encourages a more process‐oriented perspective that emphasizes procedural concerns while higher rank imbues a more result‐oriented perspective that emphasizes distributive outcomes. We considered the cultural context that characterized work relationships in our sample of respondents from a Chinese state‐owned enterprise. Significant sets of interactions supported the predicted relationships of procedural justice with three outcomes at lower levels and distributive justice with four outcomes at higher levels. Implications and extensions of these findings are considered. Copyright © 2006 John Wiley & Sons, Ltd. 相似文献
766.
767.
Using a time-varying stochastic frontier model, this paper examines the technical efficiency of firms in the iron and steel industry to try to identify the factors contributing to the industry's efficiency growth. Industry observers and policymakers tend to cite most frequently three possible sources of efficiency growth: privatization; economies of scale; and vintage of equipment. Our study corroborates these factors. Based on our findings, which pertain to 52 iron and steel firms over the period of 1978–1997, privatization is likely to improve the efficiency of iron and steel firms to a great extent as evidenced in various industries. This study also provides systematic evidence that iron and steel production shows economies of scale. In addition, newer vintages of equipment are found to be closely correlated with higher levels of efficiency. This clearly indicates that investment in new plants and equipments is critical in pursuit of efficiency in the iron and steel industry. 相似文献
768.
Ming-Song Tsai Fa-Kung Lee Chih-Chien Cheng Kuo-Yuan Hwa Mei-Leng Cheong Bo-Quing She 《黑龙江环境通报》2002,22(9):747-751
Increased fetal nuchal translucency (NT) in the first trimester is associated with adverse pregnancy outcomes. Whether the increased NT is also associated with an increased frequency of pregnancy-associated hypertension (PAH) is not known. Seven hundred and seventy-nine pregnant women who received NT-based Down syndrome screening and delivered their babies at our hospital by September 2000 were enrolled into this study. Among these women, there are 46 cases of preeclampsia, 68 cases of gestational hypertension (GH); 665 women without any adverse pregnancy outcomes served as controls. Correlation analysis demonstrated that NT MoM (multiples of median) level had a positive association with maternal diastolic blood pressure at the time of admission for delivery (r = 0.104; p < 0.01). The severity of PAH was concordant with the stepwise increase of mean NT MoM level, which was 0.88 in control, 1.07 in gestational hypertension, and 1.13 in preeclampsia (p < 0.001). Using the 95th (1.52 MoM) and 90th (1.31 MoM) percentiles of NT thickness as cut-offs, the sensitivities and odds ratios of the women at risk for developing GH after 20 weeks of gestation were 8.8%, 19.1% and 1.98, 2.15 respectively, while for preeclampsia were 10.9%, 28.3% and 2.49, 3.58 respectively. It is concluded that the pathological changes in the placenta responsible for the development of PAH may also influence the physiological decrease of NT thickness in late first trimester. However, the sensitivity of fetal NT measurement in first trimester is not sufficient as a single marker for predicting the pregnant women at risk for subsequent PAH. Copyright © 2002 John Wiley & Sons, Ltd. 相似文献
769.
770.
H B Tracy R A Lee C E Woelke G Sanborn 《Journal - Water Pollution Control Federation》1969,41(12):2062-2069