全文获取类型
收费全文 | 5322篇 |
免费 | 45篇 |
国内免费 | 21篇 |
专业分类
安全科学 | 114篇 |
废物处理 | 259篇 |
环保管理 | 370篇 |
综合类 | 850篇 |
基础理论 | 1302篇 |
环境理论 | 5篇 |
污染及防治 | 1767篇 |
评价与监测 | 416篇 |
社会与环境 | 288篇 |
灾害及防治 | 17篇 |
出版年
2023年 | 57篇 |
2022年 | 136篇 |
2021年 | 149篇 |
2020年 | 73篇 |
2019年 | 83篇 |
2018年 | 188篇 |
2017年 | 206篇 |
2016年 | 269篇 |
2015年 | 191篇 |
2014年 | 289篇 |
2013年 | 424篇 |
2012年 | 306篇 |
2011年 | 342篇 |
2010年 | 231篇 |
2009年 | 192篇 |
2008年 | 328篇 |
2007年 | 291篇 |
2006年 | 243篇 |
2005年 | 191篇 |
2004年 | 172篇 |
2003年 | 149篇 |
2002年 | 124篇 |
2001年 | 79篇 |
2000年 | 40篇 |
1999年 | 47篇 |
1998年 | 26篇 |
1997年 | 21篇 |
1996年 | 22篇 |
1995年 | 33篇 |
1994年 | 30篇 |
1993年 | 10篇 |
1992年 | 20篇 |
1991年 | 21篇 |
1990年 | 20篇 |
1989年 | 16篇 |
1988年 | 15篇 |
1987年 | 12篇 |
1986年 | 25篇 |
1985年 | 13篇 |
1984年 | 13篇 |
1983年 | 13篇 |
1982年 | 19篇 |
1981年 | 10篇 |
1980年 | 14篇 |
1972年 | 9篇 |
1966年 | 17篇 |
1965年 | 11篇 |
1957年 | 9篇 |
1956年 | 11篇 |
1954年 | 9篇 |
排序方式: 共有5388条查询结果,搜索用时 15 毫秒
241.
Ashraf M. El-Sayed John Revell Alfredo Jiménez-Perez Aimee Harper David M. Suckling 《Chemoecology》2016,26(5):187-193
The currant clearwing Synanthedon tipuliformis (Clerck) (Sesiidae) is a worldwide pest of black currants, Ribes nigrum. This moth has been observed to feed on nectar of inflorescences of Canada thistles, Cirsium arvense (L.) Scop. This work was undertaken to identify floral compound(s) produced by Canada thistles inflorescences that mediate the response of the currant clearwing. Floral volatiles were collected during the day and analysed by coupled gas chromatography/electroantennographic detection (GC/EAD) and gas chromatography/mass spectrometry (GC/MS). Three compounds consistently elicited EAD response from moth antennae and were identified by GC/MS as phenylacetaldehyde, methyl salicylate and dimethyl salicylate. When the compounds were tested individually or in various combinations in field trapping experiments, a 3-component blend attracted the largest number of female and male currant clearwings. Subsequent field trapping experiments were conducted to determine the optimal attraction dose for the ternary blend using three loadings of 1, 10 and 100 mg loaded into a polyethylene sachet. The highest catches were in traps baited with the 100 mg loading. In all trials, males and mated females were caught in significant numbers, while very low numbers of virgin females were found in the traps. In recent years the efficacy of mating disruption against currant clearwing has been reported as declining. The new kairomone blend identified in this study can be used with the sex pheromone to provide an effective control option for this important pest. 相似文献
242.
243.
244.
245.
246.
247.
248.
249.
250.
Lino J. Alvarez-Vázquez Gerardo Casal Aurea Martínez Miguel E. Vázquez-Méndez 《Environmental Modeling and Assessment》2017,22(4):279-289
In this work, we propose a technique to automatically optimize the monitoring of any distributed indicator (concentration of a substance along a river, blood pressure of a patient over time, etc.) for which a reliable estimate is previously available. From a mathematical point of view, the problem is based on obtaining a reliable estimate of the chosen indicator (e.g., by numerical simulation), and then solving a multi-objective optimization problem (with mixed real and integer variables) whose solution must provide an efficient and satisfactory monitoring strategy. As an illustrative case, we show the steps to follow in order to implement that strategy when designing a system for monitoring water quality in a river. Finally, we present and analyze the results when applying the proposed technique to study a real case in the Neuse River (North Carolina, USA). 相似文献