全文获取类型
收费全文 | 4456篇 |
免费 | 30篇 |
国内免费 | 6篇 |
专业分类
安全科学 | 69篇 |
废物处理 | 162篇 |
环保管理 | 196篇 |
综合类 | 1704篇 |
基础理论 | 894篇 |
环境理论 | 8篇 |
污染及防治 | 1064篇 |
评价与监测 | 213篇 |
社会与环境 | 176篇 |
灾害及防治 | 6篇 |
出版年
2019年 | 40篇 |
2018年 | 79篇 |
2017年 | 87篇 |
2016年 | 99篇 |
2015年 | 89篇 |
2014年 | 111篇 |
2013年 | 204篇 |
2012年 | 104篇 |
2011年 | 186篇 |
2010年 | 126篇 |
2009年 | 128篇 |
2008年 | 218篇 |
2007年 | 178篇 |
2006年 | 151篇 |
2005年 | 124篇 |
2004年 | 116篇 |
2003年 | 105篇 |
2002年 | 135篇 |
2001年 | 84篇 |
2000年 | 73篇 |
1999年 | 51篇 |
1998年 | 41篇 |
1997年 | 43篇 |
1996年 | 46篇 |
1995年 | 51篇 |
1994年 | 53篇 |
1993年 | 33篇 |
1992年 | 48篇 |
1991年 | 40篇 |
1990年 | 43篇 |
1989年 | 37篇 |
1981年 | 32篇 |
1978年 | 32篇 |
1977年 | 32篇 |
1976年 | 37篇 |
1968年 | 37篇 |
1967年 | 41篇 |
1966年 | 35篇 |
1965年 | 54篇 |
1964年 | 43篇 |
1963年 | 41篇 |
1962年 | 33篇 |
1961年 | 49篇 |
1960年 | 42篇 |
1959年 | 42篇 |
1958年 | 48篇 |
1957年 | 42篇 |
1956年 | 42篇 |
1955年 | 38篇 |
1954年 | 45篇 |
排序方式: 共有4492条查询结果,搜索用时 15 毫秒
21.
B. Beck-Friis M. Pell U. Sonesson H. Jönsson H. Kirchmann 《Environmental monitoring and assessment》2000,62(3):317-331
Composting can be a source of N2O andCH4 production. In this investigation, differentcompost heaps of organic household waste weremonitored with the focus on potential formation ofCH4 and N2O in the heaps and emission ofthese gases from the heaps. The studied compost heapshad different compost ages, turning intervals andcompost sizes. The analysed compost gases containedbetween 1–3421 L of N2O-N L-1 and 0–470 mL of CH4 L-1. The emission rates ofN2O and CH4 from the compost heaps werebetween 1–1464 mg N2O m-2 day-1 and0–119 000 mg CH4 m-2 day-1. These verylarge differences in compost gas composition andemission indicate the importance of compostmanagement. The results also give an understanding ofwhere in the composting process an increasing emissionof N2O and CH4 can occur. 相似文献
22.
23.
Monte Carlo-assisted factor analysis has been applied to a data set of 20 trace-element concentrations in tree-bark samples obtained from 123 locations in The Netherlands, with the aim to investigate the suitability of bark as a biomonitor for air pollution. A Monte Carlo approach was used to give more insight to the uncertainties and significance levels of the factor analysis results. Notwith-standing a rather strong influence of soil material on the concentration levels, factor analysis enabled the identification of five significant pollution source types, all of which corresponded with source types found in an earlier biomonitoring study in The Netherlands using epiphytic lichens. A more detailed comparison with the lichen results showed a remarkable difference in lead concentrations between bark and lichen. It was concluded that bark can be successfully employed as a biomonitor for air pollution. The power of factor analysis to adequately determine the soil contribution may render extensive sample washing procedures superfluous. 相似文献
24.
Specific PCR amplification and probe hybridization techniques were applied to examine the compositions of airborne fungi in samples from three different environments. The results from microscopic and CFU counting were compared to those of the molecular-based detections. The detection sensitivity for PCR amplifications was 9 to 73 spores and 1.3 to 19.3 CFUs per PCR reaction. The hybridization detection limit was 2 to 4 spores and 0.2 to 1.2 CFU. The hybridization method was more sensitive than PCR amplification and showed less variation among samples. Using specific PCR primers and probes we identified the presence of several fungal groups and species in the air samples. Specific detections through probe hybridization to PCR products amplified with universal or group-specific fungal primers have promising applications in the examination of air samples for environmental monitoring. 相似文献
25.
J. Altenburger Th. Dielacher P. Eder H. Ferner M. Fegerl J. Fresner O. Gelinek A. Kogler J. Jantschgi M. Nussbaumer B. Russegger H. Schnitzer K. Schauer B. Sebesta J. Seiler F. Sprenger H. Widenmeyer 《Journal of Cleaner Production》1994,2(3-4)
The paper focuses upon the organization of a federal state-funded pollution prevention project in the Styrian industry. The project includes 13 companies from the textile, pulp and paper, machine building, wood working and printed circuit board manufacturing industries, covering most of the sectors and sizes in the Styrian industry. It started in January 1994 and will last for one year. It will demonstrate the possibilities of pollution prevention and the need for further research work. This project will make use of the methods and tools that were refined in the Austrian Prepare project. As a first step, a systematic balance of all the inputs and outputs of a company is made, after which the weak points and inefficiencies of material and energy use are identified and the options for improvements, both economical and ecological, are defined. Consequently, modifications in products and production lead to a situation with less waste and emissions. The preliminary lessons from these projects are presented: as a rule, the utilities (consumption of process materials and water, cleaning, energy, preparatory and finishing steps) are treated as black boxes and usually represent a considerable optimization potential. In these areas especially there is usually a lack of information and coordination as well as a need for a systematic and comprehensive approach. Leadership in the company and creative consultants are needed for starting lasting successful pollution prevention projects. 相似文献
26.
The importance of selenium as an essential trace element has progressively emerged during the last years due to the analysis of selenium deficiency diseases and to the identification and characterization of a number of selenoenzymes. Selenium is incorporated in the catalytic site of the enzymes as an integral selenocysteine residue. The pathway of selenocysteine biosynthesis and incorporation has been elucidated recently for Escherichia coli. This article presents an overview on these subjects and describes the mechanisms which confer selenocysteine specificity in the framework of protein biosynthesis. In addition, some considerations concerning the phylogeny of selenocysteine incorporation are presented and a model for the evolution of the selenocysteine pathway is proposed. 相似文献
27.
E. Lamla F. Boschke G. Traving G. Pfotzer H. Wolter W. Walcher H. D. Dahmen H. J. Queisser W. W. Klingbeil K. Beyermann O. Müller R. R. Ernst D. Reinen H. Muth W. Becker G. Wunsch G. I. Distler L. Jaenicke H. G. v. Schnering H. Werner F. Reiff H. Schimassek W. Höll H. K. Vasil W. F. Angermeier W. Ruppel J. C. Eccles G. Spiteller H. Oettel W. Vogell P. Brosche K. J. Hsü H. -U. Schmincke 《Die Naturwissenschaften》1975,62(3):143-143
28.
29.
30.