全文获取类型
收费全文 | 614篇 |
免费 | 1篇 |
国内免费 | 2篇 |
专业分类
安全科学 | 4篇 |
废物处理 | 12篇 |
环保管理 | 29篇 |
综合类 | 364篇 |
基础理论 | 91篇 |
环境理论 | 1篇 |
污染及防治 | 95篇 |
评价与监测 | 13篇 |
社会与环境 | 8篇 |
出版年
2017年 | 11篇 |
2013年 | 23篇 |
2012年 | 10篇 |
2011年 | 9篇 |
2010年 | 7篇 |
2009年 | 13篇 |
2008年 | 15篇 |
2007年 | 10篇 |
2006年 | 8篇 |
2005年 | 6篇 |
2004年 | 11篇 |
2002年 | 8篇 |
2001年 | 10篇 |
1999年 | 13篇 |
1998年 | 6篇 |
1995年 | 6篇 |
1994年 | 8篇 |
1993年 | 7篇 |
1992年 | 9篇 |
1991年 | 12篇 |
1990年 | 7篇 |
1989年 | 8篇 |
1981年 | 7篇 |
1978年 | 6篇 |
1966年 | 6篇 |
1965年 | 7篇 |
1963年 | 13篇 |
1962年 | 8篇 |
1961年 | 7篇 |
1959年 | 9篇 |
1958年 | 11篇 |
1957年 | 6篇 |
1956年 | 9篇 |
1955年 | 10篇 |
1954年 | 6篇 |
1943年 | 7篇 |
1941年 | 7篇 |
1939年 | 6篇 |
1935年 | 7篇 |
1934年 | 7篇 |
1932年 | 6篇 |
1930年 | 9篇 |
1929年 | 10篇 |
1928年 | 8篇 |
1927年 | 11篇 |
1926年 | 15篇 |
1925年 | 12篇 |
1924年 | 6篇 |
1923年 | 6篇 |
1921年 | 9篇 |
排序方式: 共有617条查询结果,搜索用时 15 毫秒
11.
12.
13.
14.
15.
16.
17.
E. Conrad Lamon Song S. Qian Daniel D. Richter 《Journal of the American Water Resources Association》2004,40(5):1219-1229
ABSTRACT: Dynamic linear models (DLM) and seasonal trend decomposition (STL) using local regression, or LOESS, were used to analyze the 50‐year time series of suspended sediment concentrations for the Yadkin River, measured at the U.S. Geological Survey station at Yadkin College, North Carolina. A DLM with constant trend, seasonality, and a log10 streamflow regressor provided the best model to predict monthly mean log10 suspended sediment concentrations, based on the forecast log likelihood. Using DLM, there was evidence (odds approximately 69:1) that the log10 streamflow versus log10 suspended sediment concentration relationship has changed, with an approximate 20 percent increase in the log10 streamflow coefficient over the period 1981 to 1996. However, sediment concentrations in the Yadkin River have decreased during the decade of the 1990s, which has been accompanied by a concomitant increase in streamflow variability. Although STL has been shown to be a versatile trend analysis technique, DLM is shown to be more suitable for discovery and inference of structural changes (trends) in the model coefficient describing the relationship between flow and sediment concentration. 相似文献
18.
Kimmo J. Koistinen Anu Kousa Virpi Tenhola Otto Hänninen Matti J. Jantunen Lucy Oglesby 《Journal of the Air & Waste Management Association (1995)》2013,63(10):1212-1220
ABSTRACT EXPOLIS is a European multicenter (Athens, Basel, Grenoble, Helsinki, Milan, and Prague) air pollution exposure study. It is the first international, population-based, large-scale study, where personal exposures to PM2 5 aerosol particles (together with volatile organic compounds and carbon monoxide) are being monitored. EXPOLIS is performed in six different centers across Europe, the sampled aerosol concentrations vary greatly, and the mi-croenvironmental samples are not collected with the same equipment as the personal samples. Therefore careful equipment selection, methods development and testing, and thorough quality assurance and quality control (QA & QC) procedures are essential for producing reliable and comparable PM2.5 data. This paper introduces the equipment, the laboratory test results, the pilot results, the standard operating procedures, and the QA & QC procedures of EXPOLIS. Test results show good comparability and repeatability between personal and microenvironmen-tal monitors for PM2.5 at different concentration levels measured across Europe in EXPOLIS centers. 相似文献
19.
Thermodegradation of organometallics viz. RMX (where M = Mg, Ti, Pd, Sn, Si, Al; and X =halogen atom) provides corresponding haloorganics i.e. RX. 1,2‐Shifts of H and Cl on the carbene species like CH2F. CF and CFCL2, CF produced from R. CF. Si F3 (R = CH2F, CFCl2) are preferred to that of fluorine. The thermolysis of R.CF2. Si Cl3 (R = CH2F) produces chloroolefins via halogen exchange. Major products of thermal degradation of poly (vinyl chloride) (PVC) are HCl and benzene but the mechanism of PVC thermodegradation is still a matter of dispute. The thermal cracking of lignins yields substituted phenols. 相似文献
20.
Thanakorn Uan-On Otto J. Helweg 《Journal of the American Water Resources Association》1988,24(2):261-268
ABSTRACT: The Nonlinear Risk-Benefit (NRB) Algorithm includes risk as one of the objectives in a multiple-objective optimization problem. The NRB Algorithm is derived by extending the Surrogate Worth Trade-Off method to quadratic programming. This category of problem is common in water resources planning and design, especially multipurpose reservoir systems. Consequently, an example is given using the algorithm for optimally operating a multipurpose reservoir. 相似文献