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   388篇
  免费   1篇
安全科学   56篇
废物处理   15篇
环保管理   8篇
综合类   44篇
基础理论   43篇
污染及防治   154篇
评价与监测   42篇
社会与环境   26篇
灾害及防治   1篇
  2023年   5篇
  2022年   4篇
  2021年   7篇
  2020年   6篇
  2019年   18篇
  2018年   21篇
  2017年   24篇
  2016年   25篇
  2015年   8篇
  2014年   20篇
  2013年   60篇
  2012年   25篇
  2011年   19篇
  2010年   7篇
  2009年   5篇
  2008年   11篇
  2007年   17篇
  2006年   10篇
  2005年   9篇
  2004年   17篇
  2003年   14篇
  2002年   9篇
  2001年   4篇
  2000年   5篇
  1999年   2篇
  1997年   2篇
  1996年   1篇
  1993年   1篇
  1992年   1篇
  1991年   2篇
  1989年   1篇
  1988年   2篇
  1987年   2篇
  1986年   1篇
  1984年   2篇
  1982年   1篇
  1979年   2篇
  1968年   1篇
  1967年   1篇
  1965年   3篇
  1964年   1篇
  1963年   3篇
  1962年   3篇
  1961年   1篇
  1960年   3篇
  1959年   1篇
  1958年   1篇
  1931年   1篇
排序方式: 共有389条查询结果,搜索用时 15 毫秒
221.
Study of sorption kinetics of some ionic liquids on different soil types   总被引:1,自引:0,他引:1  
In the present contribution sorption kinetics experiments under static conditions were utilized in three selected ionic liquids cations (1-ethyl-3-methylimidazolium, 1-butyl-3-methylimidazolium, 1-hexyl-3-methylimidazolium chlorides) study with five type of soil, differing in total organic carbon (TOC) content. The experimental results indicate the sorption capacity growth with increase in TOC content and hydrophobicity of ionic liquid cation. The obtained kinetic sorption parameters as well as distribution coefficients (Kd) were used to estimate the sorption properties of the soil types towards the ionic liquids in question. The Gibbs free energy values indicate that ionic liquid cations sorption on soils could be generally considered as a physical adsorption with exothermic effect. But the values of −dG for studied cations sorption on soil with very high of TOC content in soil (45%) may testify to nature of chemical adsorption. Sorption of the analyzed compounds occurs probably by means of hydrogen bonds, electrostatic and π  π interaction with the organic matter and the clay minerals of the soils.  相似文献   
222.
The aim of the study was to estimate copper (Cu) accumulation efficiency in whole-fruiting bodies of 18 edible and non-edible wild growing mushrooms collected from 27 places in the Wielkopolska Voivodeship. Mushrooms were collected each time from the same places to estimate the diversity in Cu accumulation between tested mushroom species within 3 consecutive years of study (2011–2013). The study results revealed various accumulation of Cu in the whole-tested mushroom fruiting bodies. The highest mean accumulation of Cu was observed in Macrolepiota procera (119.4 ± 20.0 mg kg?1 dm), while the lowest was in Suillus luteus and Russula fellea fruiting bodies (16.1 ± 3.0 and 18.8 ± 4.6 mg kg?1 dm, respectively). Significant differences in Cu accumulation between mushroom species collected in 2011 and in the two following years (2012 and 2013) were observed. The results indicated that sporadic consumption of these mushrooms was not related to excessive intake of Cu for the human body (no toxic influence on health).  相似文献   
223.

There is no doubt that waste products from fruit and vegetable processing are difficult to manage. In that context, partial substitution of conventional energy substrates by industrial waste is an alternative, as it helps to utilize residues and at the same time to reduce the fixed cost of running business. The aim of the article is to analyse the possibilities of using fruit processing wastes for energy purposes in Poland. The assessment on a country scale was based on the data of the Central Statistical Office. Analogical analysis was based on the data collected from selected production plant. The obtained results show that the fruit processing waste can be successfully utilized for energy purposes. At the same time, problems of organizational nature should not be overlooked, as they can significantly decrease that potential. Although the amount of energy obtained from this source is basically negligible in the Polish energy balance, the environmental factor should not be ignored also. Therefore, the utilization of waste products from fruit processing should be a topic of interest, as it works in two ways, i.e., through reducing the amount of waste and increasing production of renewable energy.

  相似文献   
224.
225.
226.
Due to the increasing amount of polyurethane waste, chemical recycling of these materials is a topic of growing interest for many researchers. The primary purpose of polyurethane feedstock recycling is to recover the starting polyol. In this study glycerolysis using glycerine from two sources and two purity grades is proposed as a method of chemical recycling. The main effort of this paper focuses on the employment of commercial glycerine of analytical grade and waste glycerine without purification derived from the biodiesel production, as a decomposing agent for polyurethane recycling. In this study, the influence of polyurethane to glycerine mass ratio (PU/GL) and the type of decomposing agent on the chemical structure by FTIR, 1H NMR and GPC was examined. FTIR analysis of the glycerolysates showed absorption peaks similar to the virgin polyol. Those results are in compliance with GPC chromatograms, which showed for all samples, well-defined peak at ca. 13 min of retention time. The molecular weight of glycerolysates was ranging from 800 to 1300 g mol?1 depending on PU/GL mass ratio. The novel decomposition agent, namely waste glycerine derived from biodiesel production was successfully used in glycerolysis process.  相似文献   
227.
Lanyards are still important and common components of personal systems protecting against falls from a height. Experience with dynamic strength tests of lanyards indicates that test methods based on EN and ISO standards do not make objective assessment possible. This paper presents the results of theoretical and laboratory investigations of the performance of adjustable lanyards during fall arrest. The obtained results indicate that methods of testing and assessment based on those standards demonstrate considerable shortcomings when applied to low elongation lanyards. The assumptions for improved requirements and test methods of lanyards made of e.g., steel wire and aramid ropes are also presented.  相似文献   
228.
With the present development of digital registration and methods for processing speech it is possible to make effective objective acoustic diagnostics for medical purposes. These methods are useful as all pathologies and diseases of the human vocal tract influence the quality of a patient’s speech signal. Diagnostics of the voice organ can be defined as an unambiguous recognition of the current condition of a specific voice source. Such recognition is based on an evaluation of essential acoustic parameters of the speech signal. This requires creating a vibroacoustic model of selected deformations of Polish speech in relation to specific human larynx diseases. An analysis of speech and parameter mapping in 29-dimensional space is reviewed in this study. Speech parameters were extracted in time, frequency and cepstral (quefrency) domains resulting in diagrams that qualified symptoms and conditions of selected human larynx diseases. The paper presents graphically selected human larynx diseases.  相似文献   
229.
Nurses are often obliged to work in a 12-hr shift work system. We have decided to check whether such a working system constitutes an excessive load for nurses. On the basis of a questionnaire survey among nurses working in an 8-hr daytime shift system (169 nurses) and in a 12-hr shift (536 nurses), the amount of physical workload, work stress, and after-work activities were compared. Data analysis has shown that a 12-hr shift system is characterized by less significant physical workload but greater mental load. The nurses working in a 2-shift system were more tired after work, but they could spend more time on leisure activities and do housework. The data suggest that there are no significant contraindications for nurses to work in a 2-shift system.  相似文献   
230.
Designing fall arrest systems, which contain horizontal flexible anchor lines is an important technical problem related to the safety of people who work at a height and need horizontal freedom of movement. The article presents a numerical simulation of the dynamic performance of horizontal flexible anchor lines during fall arrest. The model of a 2-component system—a horizontal flexible anchor line and a falling rigid mass, described with a second order non-linear differential equation—is the main element of this method. This method of simulation is realised by a computer program, which allows obtaining the most important data characterising a fall arrest. The article shows laboratory tests used for the verification of this method, which turned out to be a valuable source of information and which can be used for designing fall arrest systems.  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