全文获取类型
收费全文 | 483篇 |
免费 | 10篇 |
国内免费 | 1篇 |
专业分类
安全科学 | 16篇 |
废物处理 | 17篇 |
环保管理 | 52篇 |
综合类 | 232篇 |
基础理论 | 57篇 |
污染及防治 | 81篇 |
评价与监测 | 17篇 |
社会与环境 | 9篇 |
灾害及防治 | 13篇 |
出版年
2020年 | 5篇 |
2018年 | 8篇 |
2017年 | 6篇 |
2016年 | 9篇 |
2015年 | 5篇 |
2014年 | 5篇 |
2013年 | 22篇 |
2012年 | 10篇 |
2011年 | 16篇 |
2010年 | 13篇 |
2009年 | 5篇 |
2008年 | 18篇 |
2007年 | 12篇 |
2006年 | 13篇 |
2005年 | 10篇 |
2004年 | 7篇 |
2003年 | 11篇 |
2000年 | 10篇 |
1996年 | 5篇 |
1993年 | 4篇 |
1992年 | 6篇 |
1984年 | 6篇 |
1983年 | 8篇 |
1981年 | 9篇 |
1977年 | 6篇 |
1965年 | 8篇 |
1963年 | 4篇 |
1962年 | 7篇 |
1961年 | 5篇 |
1960年 | 6篇 |
1959年 | 7篇 |
1958年 | 4篇 |
1957年 | 12篇 |
1956年 | 7篇 |
1955年 | 8篇 |
1954年 | 7篇 |
1952年 | 5篇 |
1941年 | 7篇 |
1940年 | 8篇 |
1939年 | 10篇 |
1938年 | 4篇 |
1937年 | 8篇 |
1936年 | 5篇 |
1935年 | 11篇 |
1934年 | 7篇 |
1931年 | 5篇 |
1929年 | 4篇 |
1928年 | 4篇 |
1927年 | 4篇 |
1926年 | 5篇 |
排序方式: 共有494条查询结果,搜索用时 647 毫秒
41.
H. Resit Akçakaya Ana S. L. Rodrigues David A. Keith E. J. Milner-Gulland Eric W. Sanderson Simon Hedges David P. Mallon Molly K. Grace Barney Long Erik Meijaard P. J. Stephenson 《Conservation biology》2020,34(3):561-571
Species interactions matter to conservation. Setting an ambitious recovery target for a species requires considering the size, density, and demographic structure of its populations such that they fulfill the interactions, roles, and functions of the species in the ecosystems in which they are embedded. A recently proposed framework for an International Union for Conservation of Nature Green List of Species formalizes this requirement by defining a fully recovered species in terms of representation, viability, and functionality. Defining and quantifying ecological function from the viewpoint of species recovery is challenging in concept and application, but also an opportunity to insert ecological theory into conservation practice. We propose 2 complementary approaches to assessing a species’ ecological functions: confirmation (listing interactions of the species, identifying ecological processes and other species involved in these interactions, and quantifying the extent to which the species contributes to the identified ecological process) and elimination (inferring functionality by ruling out symptoms of reduced functionality, analogous to the red-list approach that focuses on symptoms of reduced viability). Despite the challenges, incorporation of functionality into species recovery planning is possible in most cases and it is essential to a conservation vision that goes beyond preventing extinctions and aims to restore a species to levels beyond what is required for its viability. This vision focuses on conservation and recovery at the species level and sees species as embedded in ecosystems, influencing and being influenced by the processes in those ecosystems. Thus, it connects and integrates conservation at the species and ecosystem levels. 相似文献
42.
Masami Fujiwara Kurt E. Anderson Michael G. Neubert Hal Caswell 《Environmental and Ecological Statistics》2006,13(2):183-197
We present a new method for estimating a distribution of dispersal displacements (a dispersal kernel) from mark-recapture
data. One conventional method of calculating the dispersal kernel assumes that the distribution of displacements are Gaussian
(e.g. resulting from a diffusion process) and that individuals remain within sampled areas. The first assumption prohibits
an analysis of dispersal data that do not exhibit the Gaussian distribution (a common situation); the second assumption leads
to underestimation of dispersal distance because individuals that disperse outside of sampling areas are never recaptured.
Our method eliminates these two assumptions. In addition, the method can also accommodate mortality during a sampling period.
This new method uses integrodifference equations to express the probability of spatial mark-recapture data; associated dispersal,
survival, and recapture parameters are then estimated using a maximum likelihood method. We examined the accuracy of the estimators
by applying the method to simulated data sets. Our method suggests designs for future mark-recapture experiments.
Received: January 2004 / Revised: July 2005 相似文献
43.
The impact of insecticides and herbicides on the biodiversity and productivity of aquatic communities. 总被引:1,自引:0,他引:1
Dean G Thompson Keith R Solomon Barbara F Wojtaszek Andrea N Edginton Gerald R Stephenson 《Ecological applications》2006,16(5):2022-7; author reply 2027-34
44.
45.
Kurt Schubert 《Die Naturwissenschaften》1954,41(10):231-231
46.
47.
48.
The porous polymers Amberlite XAD-2 and XAD-7 were evaluated for the sampling of ethylene glycol, 2-methoxyethanol, 2-ethoxyethanol, 2-butoxyethanol and 2-ethoxyethyl acetate in work-room air. Using diethyl ether desorption, these adsorbents were found excellent for the compounds studied. 相似文献
49.
50.