全文获取类型
收费全文 | 2577篇 |
免费 | 207篇 |
国内免费 | 362篇 |
专业分类
安全科学 | 245篇 |
废物处理 | 85篇 |
环保管理 | 343篇 |
综合类 | 1101篇 |
基础理论 | 412篇 |
环境理论 | 2篇 |
污染及防治 | 598篇 |
评价与监测 | 149篇 |
社会与环境 | 126篇 |
灾害及防治 | 85篇 |
出版年
2023年 | 42篇 |
2022年 | 120篇 |
2021年 | 114篇 |
2020年 | 128篇 |
2019年 | 104篇 |
2018年 | 99篇 |
2017年 | 122篇 |
2016年 | 103篇 |
2015年 | 108篇 |
2014年 | 135篇 |
2013年 | 309篇 |
2012年 | 153篇 |
2011年 | 172篇 |
2010年 | 158篇 |
2009年 | 151篇 |
2008年 | 111篇 |
2007年 | 123篇 |
2006年 | 120篇 |
2005年 | 95篇 |
2004年 | 68篇 |
2003年 | 72篇 |
2002年 | 62篇 |
2001年 | 26篇 |
2000年 | 36篇 |
1999年 | 19篇 |
1998年 | 16篇 |
1997年 | 24篇 |
1996年 | 15篇 |
1995年 | 19篇 |
1994年 | 16篇 |
1993年 | 14篇 |
1992年 | 16篇 |
1991年 | 12篇 |
1990年 | 12篇 |
1989年 | 9篇 |
1986年 | 9篇 |
1984年 | 7篇 |
1983年 | 11篇 |
1982年 | 10篇 |
1981年 | 16篇 |
1977年 | 7篇 |
1972年 | 7篇 |
1967年 | 7篇 |
1965年 | 7篇 |
1963年 | 10篇 |
1962年 | 9篇 |
1961年 | 7篇 |
1960年 | 10篇 |
1959年 | 7篇 |
1957年 | 12篇 |
排序方式: 共有3146条查询结果,搜索用时 15 毫秒
21.
Modeling rhizofiltration: heavy-metal uptake by plant roots 总被引:1,自引:0,他引:1
P. Verma K. V. George H. V. Singh S. K. Singh A. Juwarkar R. N. Singh 《Environmental Modeling and Assessment》2006,11(4):387-394
The discovery of phytoaccumulation potential of plant species has led to its application for remediation of heavy-metal-contaminated soil and wastewater, which is termed as phytoextraction/rhizofiltration. For prediction, analysis, planning and cost-effective design of such systems, mathematical models not only are used as a screening tool but also provide optimal parameters like harvesting time, irrigation schedule, etc. Several laboratory and field scale studies have been carried out in the past, and mathematical expressions have been developed by various researchers for different phenomena like metal adsorption in soil, plant root growth with time, moisture and metal uptake by plant root, moisture movement in unsaturated zone, soil moisture relationship, etc. The complete design of any such phytoremediation program would require the knowledge of behavior of heavy-metal movement in soil, water and plant root system. In this paper, a model for simulating heavy-metal dynamics in soil, water and plant root system is developed and discussed. The governing non-linear partial differential equation is solved numerically by implicit finite difference method using Picard's iterative technique, and the formulation has been illustrated using a characteristic example. The source code is written in MATLAB. 相似文献
22.
A method is described whereby dielectrophoresis of algal cells is used to perform rapid water quality analysis, specifically detecting the presence of CuSO4. The dielectric collection spectrum of the fresh water alga Selenastrum capricornutum was determined for a range of concentrations of CuSO4 from 25 mg L(-1) to 0.25 mg L(-1) for exposure times of 15 min and 18 h. In all cases increasing the concentration of CuSO4 reduced cell collection, but a step reduction was observed in collection between 2 mg L(-1) and 5 mg L(-1). This method has potential for forming a rapid, low-cost test for water quality with broad specificity and significantly reduced analysis time compared to current methods. 相似文献
23.
采用灰色关联度分析方法,对影响城市大气环境质量的因素进行了相关分析,并对呈负相关关系的影响因素关联度计算采取了倒数化算子处理,使计算结果更切合实际。 相似文献
24.
25.
26.
The Australian buprestid beetle Merimna atrata (Coleoptera: Buprestidae) approaches forest fires because its larvae develop in freshly burnt wood. So far nothing is known
about possible sensory systems enabling the beetles to detect fires and to cope with the thermal environment close to the
flames. We found that M. atrata has two pairs of infrared (IR) organs on the ventrolateral sides of the abdomen. Each IR organ consists of a specialized
IR-absorbing area which is innervated by one thermosensitive multipolar neuron. The primary dendritic branches ramify into
more than 800 closely packed terminal endings which contain a large number of mitochondria. We called the special morphology
of the dendritic region a terminal dendritic mass. The type of IR receptor found in M. atrata is unique in insects and can best be compared with the IR organs of boid snakes.
Received: 14 August 2000 / Accepted in revised form: 18 October 2000 相似文献
27.
Horst Kress 《Die Naturwissenschaften》1981,68(1):28-33
In the salivary glands ofDrosophila different sets of proteins are synthesized during two successive developmental stages. This reprogramming is controlled by the hormone ecdysone. The results presented allow a proposal for its possible mode of action. 相似文献
28.
29.
30.