全文获取类型
收费全文 | 29664篇 |
免费 | 301篇 |
国内免费 | 196篇 |
专业分类
安全科学 | 765篇 |
废物处理 | 1286篇 |
环保管理 | 3963篇 |
综合类 | 5402篇 |
基础理论 | 7821篇 |
环境理论 | 14篇 |
污染及防治 | 7579篇 |
评价与监测 | 1826篇 |
社会与环境 | 1327篇 |
灾害及防治 | 178篇 |
出版年
2022年 | 199篇 |
2021年 | 214篇 |
2018年 | 359篇 |
2017年 | 358篇 |
2016年 | 585篇 |
2015年 | 443篇 |
2014年 | 659篇 |
2013年 | 2268篇 |
2012年 | 813篇 |
2011年 | 1162篇 |
2010年 | 932篇 |
2009年 | 981篇 |
2008年 | 1164篇 |
2007年 | 1251篇 |
2006年 | 1114篇 |
2005年 | 957篇 |
2004年 | 944篇 |
2003年 | 922篇 |
2002年 | 865篇 |
2001年 | 1100篇 |
2000年 | 817篇 |
1999年 | 490篇 |
1998年 | 340篇 |
1997年 | 370篇 |
1996年 | 362篇 |
1995年 | 454篇 |
1994年 | 416篇 |
1993年 | 378篇 |
1992年 | 371篇 |
1991年 | 397篇 |
1990年 | 387篇 |
1989年 | 375篇 |
1988年 | 362篇 |
1987年 | 330篇 |
1986年 | 285篇 |
1985年 | 282篇 |
1984年 | 358篇 |
1983年 | 318篇 |
1982年 | 368篇 |
1981年 | 298篇 |
1980年 | 261篇 |
1979年 | 286篇 |
1978年 | 253篇 |
1977年 | 221篇 |
1976年 | 188篇 |
1975年 | 215篇 |
1974年 | 238篇 |
1973年 | 220篇 |
1972年 | 200篇 |
1971年 | 190篇 |
排序方式: 共有10000条查询结果,搜索用时 11 毫秒
991.
Silvia H. Bonilla Rodrigo L. Guarnetti Cecilia M.V.B. Almeida Biagio F. Giannetti 《Journal of Cleaner Production》2010,18(1):83-91
Bamboo presents physical and mechanical characteristics, which turn it an alternative option for product development, replacing native or reforested wood. The sustainability assessment of a Dendrocalamus Giganteus species plantation in Brazil through the emergy methodology evidences a great weight of renewable (30% sej/sej) and human labour contributions (33% sej/sej). These contributions account for the great interface with environment and to the intensive work, respectively. The transformity value of bamboo production is 2.42E + 04 sej/J. The influence human labour has on the total emergy flow and on indicators is evaluated by taking into account different country locations (Brazil, Australia and China). Thus, a different transformity value for labour is assumed for each country. A ranking based on emergy sustainability index (ESI) values shows that bamboo production in China was the first placed, followed by Brazil and Australia (values of 1.18, 0.50 and 0.09, respectively). The insertion of indirect renewability embedded in labour results in the ranking modification, leading to plantation in Brazil in the first place, followed by the Australian and Chinese ones. The relative position of the bamboo systems is visualized in the ternary diagram expressed in terms of emergy. In an attempt to explore the relationship between sustainability and time, a graphic of ESI vs. global productivity is discussed in terms of a prospective evaluation. Indirect support areas of the bamboo production are calculated as a way to evaluate the sustainability-space relationship. 相似文献
992.
993.
C. M. Oliveira M. F. Camões P. Bigus A. A. Fachado R. B. Silva 《Environmental monitoring and assessment》2015,187(6):380
In this work, particulate matter was collected using an active sampling system consisting of a PM10 (<10 μm) inlet coupled to a multifold device containing six channels, connected to a vacuum pump. Each channel was equipped with a filter holder fitted with adequately chosen filters. The system was fixed on a metallic structure, which was placed on the roof of the laboratory building, at the Faculty of Sciences, in Lisbon. Sampling took place under flow-controlled conditions. Aerosols were extracted from the filters with water, in defined conditions, and the water-soluble fraction was quantified by ion chromatography (IC) for the determination of inorganic anions (Cl?, NO3 ? and SO4 2?). Equivalent sampling through the various channels was validated. Validation was based on the metrological compatibility of the content results for the various filters. Ion masses are metrologically equivalent when their absolute difference is smaller than the respective expanded uncertainty. When this condition is verified, the studied multifold device produces equivalent samples. 相似文献
994.
Sónia R. Q. Serra Ana Raquel Calapez Amaia Pérez-Bilbao Maria João Feio 《Environmental monitoring and assessment》2015,187(1):1-13
Bioassessment tools should distinguish between the effects of anthropogenic degradation in communities and natural temporal changes. The present study tests the influence of natural seasonal variability on macroinvertebrate stream communities assessed by a predictive model (PORTRIV) and a multimetric index (IPtI) calibrated for spring. The scores of PORTRIV decreased significantly between spring and autumn, and between spring and winter (ca. 37 to 53 %, respectively), while those of IPtI did not change significantly between seasons. For non-reference samples, the results of the predictive model also indicate no significant differences. A correction factor (CF) was calculated to adjust the existing differences in the model assessments between seasons, based on the percentage of variation of reference site scores from spring to autumn and winter. After the application of the CF to the OE50 scores of spring reference samples, the differences were no longer significant. Independent reference validation sites confirmed this tendency. This method has the advantage of avoiding large efforts required for the construction of databases from other seasons and the development of new models to allow the assessment of streams in seasons other than spring. Further tests with models developed in regions with more marked seasonal changes should be done to confirm its wider applicability. 相似文献
995.
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
996.
997.
998.
999.
1000.