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   1055篇
  免费   10篇
  国内免费   39篇
安全科学   51篇
废物处理   91篇
环保管理   93篇
综合类   96篇
基础理论   162篇
环境理论   1篇
污染及防治   399篇
评价与监测   147篇
社会与环境   54篇
灾害及防治   10篇
  2023年   28篇
  2022年   136篇
  2021年   113篇
  2020年   40篇
  2019年   46篇
  2018年   59篇
  2017年   69篇
  2016年   62篇
  2015年   30篇
  2014年   44篇
  2013年   127篇
  2012年   46篇
  2011年   60篇
  2010年   43篇
  2009年   30篇
  2008年   27篇
  2007年   28篇
  2006年   21篇
  2005年   11篇
  2004年   15篇
  2003年   9篇
  2002年   8篇
  2001年   7篇
  2000年   8篇
  1999年   5篇
  1998年   1篇
  1997年   2篇
  1996年   1篇
  1995年   5篇
  1994年   5篇
  1993年   1篇
  1992年   2篇
  1991年   1篇
  1990年   1篇
  1989年   1篇
  1985年   3篇
  1984年   1篇
  1983年   1篇
  1981年   1篇
  1979年   1篇
  1976年   1篇
  1974年   1篇
  1970年   1篇
  1964年   1篇
  1959年   1篇
排序方式: 共有1104条查询结果,搜索用时 687 毫秒
541.
This research covers the current status of occupational health and safety (OHS)-related practices in the informal construction segment of Pakistan. Data were collected, through interviews, from 316 construction sites employing 3577 workers. The results of the study reveal that both employers and workers lack knowledge of OHS laws/standards and no practices of this nature are enacted at these construction sites. Alarmingly, work-related accidents, whenever they happen, are not given due attention and there is no formal injury-report system. The informal construction industry employs a huge portion of the informal workforce, and lack of OHS happens at tremendous human cost. These research findings may thus play their role in strengthening the case for reforms in the sector. This study, if properly utilized, may also enable employers of the sector by increasing their knowledge about OHS practices and, as a result, trying to offer safer environments for their workers.  相似文献   
542.
Environmental Science and Pollution Research - The current work aimed to study the physical, chemical and biological properties of food wastes generated from small and medium industries by using...  相似文献   
543.

Cold supply chain (CSC) is a process that involves temperature-controlled activities ranging from the acquisition of raw materials and down to the end consumers. A sustainable cold chain supplier is the one that incorporates sustainable practices in its complete cycle of operations. This is to ensure keeping the products from going to waste, especially in the case of a developing country. To identify the driving factors towards the sustainable cold chain supplier, this study utilizes the interpretive structural modelling (ISM) approach in the first phase. Fifteen various sustainability factors were analyzed and the “utilization of renewable resources” factor concluded to be the most important driving factor. By implementing renewable resources, a supplier can be able to convert its manufacturing processes and services to sustainable assets. The second phase of this study conducts the selection of cold chain suppliers in the context of Pakistan. For this purpose, fuzzy VIKOR, a multi-criteria decision-making (MCDM) technique is incorporated to analyze eight suppliers based on fifteen distinct criteria. The results concluded Mitchell foods to be the most economically, environmentally and socially sustainable suppliers in the context of Pakistan. This study recommends providing business-friendly incentives to suppliers like Mitchells and new investors who tend to keep their operations sustainable by adopting renewable resources. Furthermore, the relaxation of taxes and creating job employability by working with sustainable suppliers can contribute positively towards economic growth and the overall society. The study holds novelty in the area of cold chain supplier selection for Pakistan by utilizing a novel approach in the form of ISM and fuzzy VIKOR techniques, thus forming a major application of this research study.

Graphic abstract
  相似文献   
544.
Environmental Science and Pollution Research - Oil spills are a major contributor to water contamination, which sets off a significant impact on the environment, biodiversity, and economy....  相似文献   
545.
Spent coffee grounds (SCG) have been used for the production of activated carbon (AC) by impregnation with different ratios of phosphoric acid at 600?°C, Xp (H3PO4/coffee): 3:130%, 4:130%, 3:150% and 4:150%. The obtained AC was characterized by BET, FTIR and SEM. BET surface area corresponds to 803.422 m2 g?1. The influences of the main parameters such as contact time, the pesticides initial concentration, adsorbent dose, pH and temperature on the efficiency of separation process were investigated during the batch operational mode. Results were modeled by adsorption isotherms: Langmuir, Freundlich and Temkin isotherms, which gave satisfactory correlation coefficients. The maximum adsorption capacities calculated from the Langmuir isotherms were 11.918?mg g?1 for carbendazim and 5.834?mg g?1 for linuron at room temperature. Adsorption kinetics of carbendazim and linuron have been studied by the pseudo-first-order, the pseudo-second-order and the intraparticle diffusion model. The results of adsorption kinetics have been fitted the best by pseudo-second-order model. The resulted data from FTIR characterization pointed to the presence of many functional groups on the AC surface. SCG adsorbent, as an eco-friendly and low-cost material, showed high potential for the removal of carbendazim and linuron from aqueous solutions.  相似文献   
546.

Ephedra alata, known as a medicinal plant in China, was used in this study as aqueous extract from aerial parts, for diabetes mellitus treatment. This study was carried out on two parts, in vitro, we tested the effect of the studied extract on the inhibition of α-glucosidase and α-amylase activities, and in vivo on Wistar male rats receiving alloxan intraperitoneally at a rate of 125 mg/kg. Extract (100, 200, and 300 mg/kg of body weight) was administrated for 28 days by oral gavage. Blood glucose, amylase, lipase, and lipid profile level were determined. Oxidative stress was evaluated by enzymatic activities of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx), and by estimation of lipid peroxidation and protein carbonyl (PC) level. Histopathological changes in pancreas were investigated under photonic microscopy using immunohistochemical procedure. Our findings showed that aqueous extract inhibited in vitro both α-glucosidase and α-amylase activities and its use in vivo at 300 mg/kg of body weight restored pancreas weight and weight gain, ameliorated significantly (p ? 0.05) biochemical parameters; it prevented the increase in lipid and protein oxidation and the decrease in enzymatic and non-enzymatic defense system. Histological study of treated animals showed a comparable healed regeneration of beta cells.

  相似文献   
547.
Objective: The probability of crash occurrence on horizontal curves is 1.5 to 4 times higher than that on tangent sections. A majority of these crashes are associated with human errors. Therefore, human behavior in curves needs to be corrected.

Methodology: In this study, 2 different road marking treatments, optical circles and herringbone patterns, were used to influence driver behavior while entering a curve on a 2-lane rural road section. A driving simulator was used to perform the experiment. The simulated road sections are replicas of 2 real road sections in Flanders.

Results: Both treatments were found to reduce speed before entering the curve. However, speed reduction was more gradual when optical circles were used. A herringbone pattern had more influence on lateral position than optical circles by forcing drivers to maintain a safe distance from opposing traffic in the adjacent lane.

Conclusion: The study concluded that among other low-cost speed reduction methods, optical circles are effective tools to reduce speed and increase drivers’ attention. Moreover, a herringbone pattern can be used to reduce crashes on curves, mainly for head-on crashes where the main problem is inappropriate lateral position.  相似文献   

548.
Environmental Science and Pollution Research - The Caspian Sea is the largest land-locked lake in the world that includes numerous endemic species. Because of its enclosed nature, the pollutants...  相似文献   
549.
550.
The present research deals with the development of a new heterogeneous photocatalysis and Fenton hybrid system for the removal of color from textile dyeing wastewater as Rhodamine B (RhB) solutions by using Fe2+/H2O2/Nb2O5 as a photocatalytic system. The application of this photocatalytic system for the decolorization of dye contaminants is not reported in the literature yet. Different parameters like dye concentration, Nb2O5/Fe2+ catalyst amount, pH, and H2O2 concentration have been studied. The optimum conditions for the decolorization of the dye were initial concentration of 10 mg L?1 of dye, pH 4, and Nb2O5/Fe2+ catalyst concentration of 0.5 g L?1/50 mg L?1. The optimum value of H2O2 concentration for the conditions used in this study was 700 mg L?1. Moreover, the efficiency of the Nb2O5/photo-Fenton hybrid process in comparison to photo-Fenton alone and a dark Fenton process as a control experiment to decolorize the RhB solution has been investigated. The combination of photo-Fenton and Nb2O5 catalysts has been proved to be the most effective for the treatment of such type of wastewaters. The results revealed that the RhB dye was decolorized in a higher percent (78 %) by the Nb2O5/photo-Fenton hybrid process (Fe2+/H2O2/Nb2O5/UV) than by the photo-Fenton process alone (37 %) and dark Fenton process (14 %) after 120 min of treatment. Moreover, the Nb2O5 catalyst as a heterogeneous part of the photocatalytic system was demonstrated to have good stability and reusability.  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