首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   460篇
  免费   24篇
  国内免费   29篇
安全科学   33篇
废物处理   18篇
环保管理   72篇
综合类   94篇
基础理论   103篇
环境理论   2篇
污染及防治   123篇
评价与监测   32篇
社会与环境   29篇
灾害及防治   7篇
  2023年   10篇
  2022年   24篇
  2021年   22篇
  2020年   9篇
  2019年   22篇
  2018年   25篇
  2017年   22篇
  2016年   32篇
  2015年   25篇
  2014年   31篇
  2013年   45篇
  2012年   18篇
  2011年   33篇
  2010年   22篇
  2009年   19篇
  2008年   20篇
  2007年   15篇
  2006年   16篇
  2005年   12篇
  2004年   9篇
  2003年   14篇
  2002年   14篇
  2001年   12篇
  2000年   11篇
  1999年   5篇
  1998年   6篇
  1997年   1篇
  1996年   2篇
  1995年   3篇
  1993年   2篇
  1992年   1篇
  1991年   1篇
  1990年   1篇
  1989年   3篇
  1988年   2篇
  1982年   1篇
  1979年   1篇
  1973年   1篇
  1966年   1篇
排序方式: 共有513条查询结果,搜索用时 31 毫秒
221.
Understanding of hunter preferences for hunting lease attributes is important to landowners because such knowledge provides key information for managing and marketing fee-hunting in order to maximize revenues. Premised on this insight, we used attribute based modeling to investigate how hunter preferences for potential leases were influenced by lease and hunter-specific attributes. A mail survey of Mississippi licensed hunters provided the necessary data. Estimation results based on McFadden conditional logit regression suggested that lease attributes including game diversity, lease location relative to hunter residence, lease size, lease duration and lease rate influenced willingness to pay for additional units of lease attributes. Depending on the specific levels of these attributes, WTP could vary as much as $5.70 per acre. Of the hunter-specific attributes, age and income significantly influenced hunter decision to buy a lease or opt for status quo. Results of this study should assist landowners in increasing financial returns from fee-hunting endeavors through appropriate changes to their hunting access policies and wildlife management activities in response to hunter preferences regarding lease attributes.  相似文献   
222.
Public and private organizations need a robust approach to prepare, respond, and recover from cyber-attacks. This perspective article will refer to such an approach as Cyber First AID—adaptable, integrated, and deliberate. Adaptable describes that one size does not fit all; Integrated means the effort is throughout the organization; and Deliberate describes plans that are reviewed periodically and practiced, in which all members of the organization know their respective roles and responsibilities. The article outlines a decision-making process for how to minimize the impacts of cyber threats, maintain stakeholder and customer confidence, and help organizations to adaptively manage and respond to cyber threats in rapidly changing cyber environments.  相似文献   
223.
为减少烯烃类爆炸事故带来的严重危害,采用国际通用的20L球型爆炸测试装置测试了常温初始压力为0.1 MPa条件下,4种常见烯烃的爆炸特性参数.结果表明,随着烯烃含量的增加各项爆炸特性参数均呈现出先增大后减小的特征,最大爆炸压力和爆炸指数均在化学计量比附近获得,4种烯烃最大爆炸压力分别为乙烯1.5 MPa、丙烯1.3 MPa、正丁烯1.5 MPa、异丁烯1.6 MPa,爆炸指数分别为16.56 (MPa·m)/s、7.37(MPa·m)/s、16.98 (MPa·m)/s、29.07(MPa· m)/s.  相似文献   
224.
Bow tie diagrams have become a popular method for risk analysis and safety management. This tool describes the whole scenario of a given risk graphically, and proposes preventive and protective barriers to reduce, respectively, its occurrence and its severity. The weakness of bow tie diagrams is that they are restricted to a graphical representation of different scenarios exclusively designed by experts that ignore the dynamic aspect of real systems. Thus, constructing bow tie diagrams in an automatic and dynamic way remains a real challenge. This paper proposes a new Bayesian approach to construct bow tie diagrams from real data and improve them by adding a new numerical that enables us to implement the appropriate preventive and protective barriers in a dynamic manner.  相似文献   
225.
为提高低密度聚乙烯(LDPE)阻燃性能和阻燃LDPE复合材料的力学性能与抑烟性能,采用原位聚合法制备三聚氰胺-甲醛(MF)树脂包覆二乙基次磷酸铝(ADP)的MF@ADP微胶囊,再引入三聚氰胺聚磷酸(MPP)与MF@ADP进行协效复配,熔融共混制备阻燃LDPE复合材料。通过氧指数、热重分析、力学测试和烟密度测试等研究复合材料的阻燃、力学和抑烟性能。研究结果表明:MF@ADP微胶囊能改善阻燃剂与复合材料之间的相容性,与MPP复配构成的磷-氮膨胀阻燃体系能有效提高LDPE的抑烟性能;当MF@ADP∶MPP的质量比为2∶1时,材料的LOI达到了30.6%,垂直燃烧测试达到UL-94 V0级,拉伸强度为11.8 MPa,且形成的P/N/O高聚物炭层稳定性更高,可减少LDPE燃烧释放的烟雾量。  相似文献   
226.
Environmental Science and Pollution Research - Karlodinium veneficum is a toxic benthic globally distributed dinoflagellate which has direct impacts on human health and the environment. Early and...  相似文献   
227.
228.
229.
Dechlorane Plus(DP), a flame retardant used as an alternative to decabromodiphenylether, has been frequently detected in organisms, indicating its bioaccumulation and biomagnification potential in aquatic and terrestrial species. However, little data is available on the bioaccumulation of DP in amphibians. Dechlorane Plus and its analogs(DPs) were detected in the liver, muscle and brain tissues of wild frogs(Rana limnocharis), which were collected from an e-waste recycling site, Southeast China. DP, Mirex, Dec 602 and a dechlorinated compound of DP(anti-Cl11-DP) varied in the range of 2.01–291, 0.650–179, 0.260–12.4, and not detected(nd)–8.67 ng/g lipid weight, respectively. No difference of tissue distribution was found for syn-DP, Mirex and Dec 602 between the liver and muscle tissue(liver/muscle concentration ratio close to 1, p 0.05). However, higher retention was observed for anti-DP and anti-Cl11-DP in the frog muscle relative to the liver tissue(liver/muscle concentration ratio 1, p 0.05). Additionally, the blood-brain barrier was found to work efficiently to suppress these compounds entering brain tissues in this species(liver/brain concentration ratio 1, p 0.05), and the molecular weight was a key factor impacting the extent of the blood-brain barrier. Compared to levels in the muscle and brain tissue, a preferential enrichment of syn-DP was observed in the liver tissue, suggesting the occurrence of stereo-selective bioaccumulation in the wild frog.  相似文献   
230.
This work described the development, optimization and validation of an analytical method for rapid detection of multiple-class pharmaceuticals in both municipal wastewater and sludge samples based on ultrasonic solvent extraction, solid-phase extraction, and ultra high performance liquid chromatography-tandem mass spectrometry quantification. The results indicated that the developed method could effectively extract all the target pharmaceuticals (25) in a single process and analyze them within 24 min. The recoveries of the target pharmaceuticals were in the range of 69%-131% for wastewater and 54%-130% for sludge at different spiked concentration levels. The method quantification limits in wastewater and sludge ranged from 0.02 to 0.73 ng/L and from 0.02 to 1.00μg/kg, respectively. Subsequently, this method was validated and applied for residual pharma- ceutical analysis in a wastewater treatment plant located in Beijing, China. All the target pharmaceuticals were detected in the influent samples with concentrations varying from 0.09 ng/L (tiamulin) to 15.24 μg/L (caffeine); meanwhile, up to 23 pharmaceuticals were detected in sludge samples with concentrations varying from 60 ng/kg (sulfamethizole) to 8.55 mg/kg (ofloxacin). The developed method demonstrated its selectivity, sensitivity, and reliability for detecting multiple-class pharmaceuticals in complex matrices such as municipal wastewater and sludge.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号