全文获取类型
收费全文 | 884篇 |
免费 | 10篇 |
国内免费 | 15篇 |
专业分类
安全科学 | 51篇 |
废物处理 | 20篇 |
环保管理 | 125篇 |
综合类 | 140篇 |
基础理论 | 223篇 |
环境理论 | 1篇 |
污染及防治 | 227篇 |
评价与监测 | 79篇 |
社会与环境 | 35篇 |
灾害及防治 | 8篇 |
出版年
2023年 | 7篇 |
2022年 | 4篇 |
2021年 | 7篇 |
2020年 | 6篇 |
2019年 | 11篇 |
2018年 | 17篇 |
2017年 | 15篇 |
2016年 | 18篇 |
2015年 | 24篇 |
2014年 | 15篇 |
2013年 | 99篇 |
2012年 | 35篇 |
2011年 | 59篇 |
2010年 | 41篇 |
2009年 | 44篇 |
2008年 | 54篇 |
2007年 | 44篇 |
2006年 | 34篇 |
2005年 | 30篇 |
2004年 | 27篇 |
2003年 | 26篇 |
2002年 | 33篇 |
2001年 | 16篇 |
2000年 | 17篇 |
1999年 | 6篇 |
1998年 | 13篇 |
1997年 | 9篇 |
1996年 | 13篇 |
1995年 | 9篇 |
1994年 | 13篇 |
1993年 | 9篇 |
1992年 | 11篇 |
1991年 | 14篇 |
1990年 | 8篇 |
1989年 | 8篇 |
1988年 | 4篇 |
1987年 | 5篇 |
1986年 | 6篇 |
1985年 | 9篇 |
1984年 | 5篇 |
1982年 | 7篇 |
1981年 | 6篇 |
1978年 | 5篇 |
1977年 | 4篇 |
1976年 | 3篇 |
1975年 | 3篇 |
1971年 | 4篇 |
1969年 | 4篇 |
1960年 | 4篇 |
1956年 | 3篇 |
排序方式: 共有909条查询结果,搜索用时 15 毫秒
71.
J. Roger McHenry Jerry C. Ritchie Frank R. Schiebe 《Journal of the American Water Resources Association》1977,13(1):81-92
ABSTRACT: The total suspended sediment loads of four north Mississippi reservoirs were determined from measurements of concentrations of suspended sediment in a vertical profile at several locations on each reservoir made during the year. These data were combined with the stage-height and known stage-volume relationships for each reservoir in a numerical integration to determine the total suspended sediment in the water body. Total suspended sediments were estimated using the product of the suspended sediment concentration in the surface water by the appropriate reservoir volume. The averaged ratios of the estimated to measured suspended sediment loads for each reservoir exceeded 0.90. Since the concentration of suspended sediments in surface waters of north Mississippi reservoirs has been shown as highly correlated with spectral reflectance, estimating the total suspended sediment of these reservoirs using remotely sensed spectral reflectance data is possible. 相似文献
72.
Frank L. Kudrna 《Journal of the American Water Resources Association》1977,13(4):825-834
ABSTRACT: The Chicago Metropolitan Floodwater Management Plan is a cooperative planning program under Public Law 566 of the 83rd Congress (The Watershed Protection and Flood Prevention Act). The planning effort was jointly sponsored by the U.S. Department of Agriculture, Soil Conservation Service, and the Metropolitan Sanitary District of Greater Chicago. The project is unique in that it studies a 1260 square mile (3266 sq. kilometer) watershed, which is approximately 35 percent urbanized and contains approximately 7.5 million people. At present, approximately 4.4 percent or 330,600 people live in a floodplain. It is presently estimated that 80,000 acres (32,000 ha.) of the study area are subject to flooding with a current average annual damage estimated at approximately $10 million. The Plan which has been developed to reduce or eliminate these damages is divided into six separate watershed plans, and has been developed through extensive use of local citizen watershed steering committees. The paper discusses the planning process, public participation and implementation both at an overall river basin level and watershed case study level. 相似文献
73.
74.
Katharina Bunse Matthias Vodicka Paul Schönsleben Marc Brülhart Frank O. Ernst 《Journal of Cleaner Production》2011,19(6-7):667-679
For governments and for manufacturing companies, global warming, rising energy prices, and customers’ increasing ecological awareness have pushed energy efficient manufacturing to the top of the agenda. Governments and companies are both striving to identify the most effective measures to increase energy efficiency in manufacturing processes. Based on results of a recent EU-funded roadmapping project, this paper highlights the needs of industrial companies for integrating energy efficiency performance in production management. First, it analyses concepts and tools for measurement, control and improvement of energy efficiency in production management proposed in literature. Second, the paper outlines that ICT tools and standardization are important enablers for energy efficient manufacturing. Third, industrial needs in these areas are presented based on expert interviews. The industrial needs thus identified are contrasted with concepts proposed in literature to point out the implementation gaps between practice and theory. The paper demonstrates that there exists a gap between the solutions available and the actual implementation in industrial companies. It concludes by deriving requirements for energy management in production that future collaborative research projects should address. 相似文献
75.
76.
77.
78.
79.
A maize (Zea mays L.) hybrid was infested with 30 southwestern corn borer [Diatraea grandiosella (Dyar)] larvae per plant at 4, 5, 6, 7 or 8 weeks after planting in a three-year study conducted at Mississippi State, Mississippi. Visual ratings of leaf feeding damage were highest when plants were infested 5 weeks after planting. Plant height increased linearly with the age of plants at infestation. Height of infested plants was significantly less than uninfested plants only when infestations were made 4 weeks after planting. The relationship between age of plants at infestation and yield was curvilinear. Yields were significantly reduced at all infestation times; however, the least yield reduction occurred when plants were infested 6 weeks after planting. To evaluate resistance to southwestern corn borer damage, infestation at 4 or 5 weeks after planting appeared to be most satisfactory. Yield reductions following infestation at 7 and 8 weeks after planting indicated that, when infestations are late, leaf feeding damage ratings alone may not be satisfactory indicators of plant damage. 相似文献
80.
The Science of Nature - 相似文献