全文获取类型
收费全文 | 4494篇 |
免费 | 77篇 |
国内免费 | 43篇 |
专业分类
安全科学 | 170篇 |
废物处理 | 145篇 |
环保管理 | 722篇 |
综合类 | 762篇 |
基础理论 | 1187篇 |
环境理论 | 11篇 |
污染及防治 | 1074篇 |
评价与监测 | 284篇 |
社会与环境 | 206篇 |
灾害及防治 | 53篇 |
出版年
2023年 | 24篇 |
2022年 | 36篇 |
2021年 | 61篇 |
2020年 | 37篇 |
2019年 | 43篇 |
2018年 | 102篇 |
2017年 | 120篇 |
2016年 | 127篇 |
2015年 | 117篇 |
2014年 | 123篇 |
2013年 | 305篇 |
2012年 | 207篇 |
2011年 | 278篇 |
2010年 | 195篇 |
2009年 | 208篇 |
2008年 | 240篇 |
2007年 | 271篇 |
2006年 | 255篇 |
2005年 | 175篇 |
2004年 | 145篇 |
2003年 | 148篇 |
2002年 | 152篇 |
2001年 | 91篇 |
2000年 | 92篇 |
1999年 | 65篇 |
1998年 | 56篇 |
1997年 | 71篇 |
1996年 | 57篇 |
1995年 | 73篇 |
1994年 | 58篇 |
1993年 | 44篇 |
1992年 | 43篇 |
1991年 | 32篇 |
1990年 | 29篇 |
1989年 | 20篇 |
1988年 | 25篇 |
1987年 | 22篇 |
1986年 | 27篇 |
1985年 | 24篇 |
1984年 | 35篇 |
1983年 | 26篇 |
1982年 | 26篇 |
1981年 | 26篇 |
1980年 | 27篇 |
1979年 | 37篇 |
1978年 | 22篇 |
1977年 | 24篇 |
1976年 | 15篇 |
1975年 | 13篇 |
1957年 | 11篇 |
排序方式: 共有4614条查询结果,搜索用时 875 毫秒
51.
52.
53.
Peter R. Brown Neil I. Huth Peter B. Banks Grant R. Singleton 《Agriculture, ecosystems & environment》2007,120(2-4):405-415
Developing a relationship between pest abundance and damage to crops is essential for the calculation of economic injury levels (EIL) leading to informed management decisions. The crop modelling framework, APSIM, was used to simulate the impact of mouse damage on yield loss on wheat where a long-term dataset on the density of mice was available (1983–2003). The model was calibrated using results from field trials where wheat plants were hand clipped to imitate mouse damage. The grazing effect of mice was estimated using the population density, daily intake per mouse and the proportion of wheat grain and plant tissue in the diet to determine yield loss. The mean yield loss caused by mice was 12.4% (±5.4S.E.; range −0.5 to 96%). There were 7/21 years when yield loss was >5%. A damage/abundance relationship was constructed and a sigmoidal curve explained 97% of variation when accounting for different trajectories of mouse densities from sowing to harvest. The majority of damage occurred around emergence of the crop when mouse densities were >100 mice ha−1. This is the first time that field data on mouse density and a crop simulation model have been combined to estimate yield loss. The model examines the efficacy of baiting and how to estimate EILs. Because the broadscale application of zinc phosphide is cheap and effective, the EIL is very low (<1% yield loss). The APSIM model is highly flexible and could be used for other vertebrate pests in a range of crops or pastures to develop density/damage relationships and to assist with management. 相似文献
54.
Yuen Tannirandorn Umberto Nicolini Peter C. Nicolaidis Nicholas M. Fisk Sabaratnam Arulkumaran Charles H. Rodeck 《黑龙江环境通报》1990,10(3):189-193
Twelve second-trimester fetuses with cystic hygroma underwent fetal blood sampling for rapid karyotyping, haematologic evaluation, and blood gas analysis. An abnormal karyotype was found in seven cases: monosomy X in five, trisomy 21 in one, and trisomy 13 in the other. Eight often fetuses undergoing blood gas analysis showed hypoxaemia, five of which were growth-retarded. Nine pregnancies were terminated. Of the remaining three, only one fetus survived the perinatal period. 相似文献
55.
Salomao O. Bandeira Rui Paula e Silva Jose Paula Adriano Macia Lars Hernroth Almeida T. Guissamulo Domingos Z.Bergman 《Ambio-人类环境杂志》2002,31(7):606-609
本文概述了莫桑比克包括渔业在内的海洋生物学研究的发展情况.莫桑比克的海岸线约为3000km,海洋的生物资源在莫桑比克的社会中起着重要的作用,主要是作为人们的蛋白质来源以及收入和出口创汇的来源. 相似文献
56.
Torvanger Asbjørn Rypdal Kristin Kallbekken Steffen 《Mitigation and Adaptation Strategies for Global Change》2005,10(4):693-715
Carbon dioxide (CO2) capture and storage is increasingly being considered as an important climate change mitigation option. This paper explores
provisions for including geological CO2 storage in climate policy. The storage capacity of Norway's Continental Shelf is alone sufficient to store a large share
of European CO2 emissions for many decades. If CO2 is injected into oil reservoirs there is an additional benefit in terms of enhanced oil recovery. However, there are significant
technical and economic challenges, including the large investment in infrastructure required, with related economies of scale
properties. Thus CO2 capture, transportation and storage projects are likely to be more economically attractive if developed on a large scale,
which could mean involving two or more nations. An additional challenge is the risk of future leakages from storage sites,
where the government must take on a major responsibility. In institutional and policy terms, important challenges are the
unsettled status of geological CO2 storage as a policy measure in the Kyoto Protocol, lack of relevant reporting and verification procedures, and lack of decisions
on how the option should be linked to the flexibility mechanisms under the Kyoto Protocol. In terms of competitiveness with
expected prices for CO2 permits under Kyoto Protocol trading, the relatively high costs per tonne of CO2 stored means that geological CO2 storage is primarily of interest where enhanced oil recovery is possible. These shortcomings and uncertainties mean that
companies and governments today only have weak incentives to venture into geological CO2 storage. 相似文献
57.
58.
Letter to the Editors 总被引:1,自引:0,他引:1
Peter H. Duesberg 《Die Naturwissenschaften》1990,77(3):97-102
59.
60.