全文获取类型
收费全文 | 195篇 |
免费 | 2篇 |
国内免费 | 3篇 |
专业分类
安全科学 | 55篇 |
废物处理 | 1篇 |
环保管理 | 24篇 |
综合类 | 93篇 |
基础理论 | 3篇 |
污染及防治 | 3篇 |
评价与监测 | 12篇 |
社会与环境 | 7篇 |
灾害及防治 | 2篇 |
出版年
2023年 | 1篇 |
2021年 | 5篇 |
2020年 | 6篇 |
2019年 | 2篇 |
2018年 | 2篇 |
2017年 | 8篇 |
2016年 | 3篇 |
2015年 | 9篇 |
2014年 | 12篇 |
2013年 | 4篇 |
2012年 | 9篇 |
2011年 | 12篇 |
2010年 | 5篇 |
2009年 | 9篇 |
2008年 | 7篇 |
2007年 | 9篇 |
2006年 | 4篇 |
2005年 | 4篇 |
2004年 | 6篇 |
2003年 | 15篇 |
2002年 | 6篇 |
2001年 | 7篇 |
2000年 | 8篇 |
1999年 | 11篇 |
1998年 | 4篇 |
1997年 | 5篇 |
1996年 | 8篇 |
1995年 | 6篇 |
1994年 | 4篇 |
1993年 | 2篇 |
1992年 | 1篇 |
1990年 | 2篇 |
1985年 | 1篇 |
1983年 | 2篇 |
1982年 | 1篇 |
排序方式: 共有200条查询结果,搜索用时 93 毫秒
101.
Chao Luo Weibin Ma Yulie Gong 《Journal of Loss Prevention in the Process Industries》2011,24(5):695-698
An experimental study for fluid hydrodynamic characteristics in thin water films falling down the outside of a vertical tube was performed with the analysis of several factors about the uniformity and stability of the film. Liquid evaporation is of major interest for many fields in process engineering. One of these is chemical process engineering, where evaporation of liquids and generation of super heated steam is mandatory for numerous processes. Generally, this is performed by the use of classical pool boiling and evaporation process equipment, providing relatively limited performance. The performance of the film distributor will affect the production capacity and service life of the evaporator. In this publication a novel falling-film distributor which is used annular gap and inlet tube rotated tangentially 270° to guarantee the film uniformity is presented. Experimental data suggested that there is optimum annular gap distance is between 1.5 and 2.0 mm and the spray density should be controlled between 250 and 700 kg m−1 h−1. Several suggestions for evaporator design are proposed. 相似文献
102.
Pickett ST Cadenasso ML Grove JM Boone CG Groffman PM Irwin E Kaushal SS Marshall V McGrath BP Nilon CH Pouyat RV Szlavecz K Troy A Warren P 《Journal of environmental management》2011,92(3):331-362
Urban ecological studies, including focus on cities, suburbs, and exurbs, while having deep roots in the early to mid 20th century, have burgeoned in the last several decades. We use the state factor approach to highlight the role of important aspects of climate, substrate, organisms, relief, and time in differentiating urban from non-urban areas, and for determining heterogeneity within spatially extensive metropolitan areas. In addition to reviewing key findings relevant to each state factor, we note the emergence of tentative "urban syndromes" concerning soils, streams, wildlife and plants, and homogenization of certain ecosystem functions, such as soil organic carbon dynamics. We note the utility of the ecosystem approach, the human ecosystem framework, and watersheds as integrative tools to tie information about multiple state factors together. The organismal component of urban complexes includes the social organization of the human population, and we review key modes by which human populations within urban areas are differentiated, and how such differentiation affects environmentally relevant actions. Emerging syntheses in land change science and ecological urban design are also summarized. The multifaceted frameworks and the growing urban knowledge base do however identify some pressing research needs. 相似文献
103.
104.
Reverse logistics and green product design are green supply chain management practices that are being implemented to demonstrate firm's commitment to environmental sustainability. The generation of waste from electrical and electronic equipments prompts the viability of product recovery to salvage invested material and energy. Selection of various reverse logistics product disposition options relies on products’ residual value and the accessibility of reusable content for re-entry in forward supply chain. This study explores the effect of green product design and resource commitment on reverse logistics product disposition by employing empirical analysis on 89 returned mail survey received from ISO14001 certified electrical and electronic manufacturing firms in Malaysia. The results indicated that design for disassembly is necessary to harvest valuable inventories from every product disposition options except of disposal whereas design for environment and commitment of resources have slight influence on repair and disposal activities. As the evidences show that green product design and reverse logistics product disposition are interrelated, firms ought to undertake environmentally proactive approaches to generate benefits from resources that are undeservingly discarded as landfill waste. 相似文献
105.
Triboelectric charging of powders during pneumatic transport can lead to hazardous spark discharges. In this study, the charging process was studied numerically by means of large eddy simulations. A range of design parameters was then analyzed statistically applying the Design of Experiments methodology. It is shown that the electric charge of the powder can be significantly decreased by reducing the conveying air velocity. Furthermore, the usage of pipes of a larger diameter and the application of higher solid mass flow rates also reduce the powder charge. 相似文献
106.
矿井提升机的安全可靠性分析与设计 总被引:11,自引:2,他引:11
矿井提升机是井下作业提升物料和人员的关键设备 ,素有矿井咽喉之称。安全、可靠与高效是提升机设计与分析的基本准则与要求。笔者概要分析了矿井提升机的安全可靠性 ;提出了相应的设计要点 ,并对各子系统中相对薄弱环节的安全可靠性进行了探讨。以上科研成果 ,为提升机械的进一步研究与开发提供了一定的理论参考依据 相似文献
107.
高层建筑发生火灾后,保护人员的安全是个十分重要的问题。把楼内的一定区域设计为避难区或安全区,并对该区进行正压送凤,可以防止火灾烟气进入,从而使人们免受烟气的影响。本文讨论了避难区内外压差的计算方法,指出此压差取在25-85Pa范围内为宜,分析了外界风速、建筑物的窗户破裂及门的开启或关闭对压差产生的影响,并对间接加压方案作了探讨. 相似文献
108.
The use of lead poses significant hazardous occupational exposure to workers in the electronics industry, and also causes environmental challenges at the end of product life. For the past decade, there has been a global effort in the electronics industry to initiate a move towards using lead-free materials for the production of printed circuit boards. However, there are technical and economic challenges, such as long term reliability and rework capability, that remain to hinder the universal implementation of lead-free materials. As a result, many electronics products are still currently manufactured and assembled using materials containing lead.The costs for investigating and evaluating the various lead-free electronics materials and manufacturing processes can be cost prohibitive for an individual company to undertake alone. Consequently, the New England Lead-free Electronics Consortium was formed as a collaborative effort of New England companies spanning the electronics supply chain to help move the industry towards lead-free electronics. The Consortium is a working collaboration of industry, government, and academia. For the past several years, the Consortium has conducted research and testing for using various lead-free materials for the manufacture of printed circuit boards. The Consortium has been successful in identifying lead-free materials and processes to address the challenges of assembly and rework. The Consortium is currently conducting research to address the long-term reliability challenge of lead-free electronics. 相似文献
109.
Process design can be influenced most in the early phases. Here, screening methods play a major role, as they reduce the complexity of a system studied by making a pre-selection from a set of alternatives available. The remaining alternatives can be analyzed in more detail in the subsequent design process, which increases design efficiency. The present paper focuses on a multi-stage screening approach for use in the early process development phase in particular. This approach is based on the use of non-compensatory decision support methods that are transferred to life cycle assessment. It may be divided into a first stage, in which the decision matrix used is developed on the basis of decision analysis principles, and a second stage, in which the decision matrix developed is further processed using non-compensatory decision support methods. An example of such a method is the pareto-dominance analysis applied here. The approach proposed is validated by application to the process of biomass gasification in supercritical water, which is being developed at the moment. Here, screening is performed to identify those life cycles, the potential environmental impacts of which contribute most to the total impacts. Attributes are selected in line with the requirement of a simple, but still sufficient modeling of these environmental impacts. By pareto-dominance analysis, emissions from the gasification of sewage sludge, the pre-chain of natural gas production, and from the construction of the supercritical gasification plant are identified to dominate over the remaining life cycles studied. Apart from the predominating alternatives, it is of particular importance to know the dominated alternatives. Due to their small shares in the result, no or only a small expenditure is needed to identify improvement potentials of these alternatives. 相似文献
110.
The aim of this work is the study of p-nitrophenol (PNP) removal, as a nitroaromatic compound, using a hybridized photo-thermally activated potassium persulfate (KPS) in a fully recycled batch reactor. Response surface method was used for modeling the process. Reaction temperature, KPS initial dosage and initial pH of the solution were selected as variables, besides PNP degradation efficiency was selected as the response. ANOVA analysis reveals that a second order polynomial model with F-value of 41.7, p-value of 0.0001 and regression coefficient of 0.95 is able to predict the response. Based on the model, the process optimum conditions were introduced as initial pH of 4.5, [KPS]0 = 1452 mg/L and T = 66 °C. Also experiments showed that using thermolysis and photolysis of the persulfate simultaneously, the role of thermolysis is not considerable. A pseudo first order kinetic model was established to describe the degradation reaction. Operational cost, as a vital industrial criterion, was estimated so that the condition of initial pH of 4.5, [KPS]0 = 1452 mg/L and T = 25 °C showed the highest cost effective case. Under the preferred mild condition, the process will reach to 84% and 89% of degradation and mineralization efficiencies, after 60 and 120 min, respectively. 相似文献