全文获取类型
收费全文 | 530篇 |
免费 | 18篇 |
专业分类
各国政治 | 29篇 |
工人农民 | 47篇 |
世界政治 | 145篇 |
外交国际关系 | 54篇 |
法律 | 189篇 |
中国政治 | 4篇 |
政治理论 | 78篇 |
综合类 | 2篇 |
出版年
2023年 | 2篇 |
2022年 | 6篇 |
2021年 | 2篇 |
2020年 | 11篇 |
2019年 | 7篇 |
2018年 | 20篇 |
2017年 | 20篇 |
2016年 | 20篇 |
2015年 | 11篇 |
2014年 | 14篇 |
2013年 | 87篇 |
2012年 | 16篇 |
2011年 | 17篇 |
2010年 | 25篇 |
2009年 | 14篇 |
2008年 | 25篇 |
2007年 | 33篇 |
2006年 | 18篇 |
2005年 | 28篇 |
2004年 | 23篇 |
2003年 | 16篇 |
2002年 | 17篇 |
2001年 | 9篇 |
2000年 | 9篇 |
1999年 | 10篇 |
1998年 | 2篇 |
1997年 | 3篇 |
1996年 | 2篇 |
1995年 | 6篇 |
1994年 | 5篇 |
1993年 | 3篇 |
1992年 | 8篇 |
1991年 | 4篇 |
1990年 | 2篇 |
1989年 | 2篇 |
1988年 | 2篇 |
1987年 | 7篇 |
1986年 | 4篇 |
1985年 | 6篇 |
1983年 | 5篇 |
1981年 | 2篇 |
1978年 | 2篇 |
1976年 | 3篇 |
1975年 | 2篇 |
1974年 | 3篇 |
1973年 | 4篇 |
1967年 | 1篇 |
1966年 | 1篇 |
1965年 | 1篇 |
1964年 | 1篇 |
排序方式: 共有548条查询结果,搜索用时 15 毫秒
271.
The nature of blood aerosols produced in physiological studies of an upright subject expiring small volumes through straws, spitting and mouthing sounds, and a semi-prone subject spitting through a bloody mouth or snorting through a single nasal orifice and by a simplified physical model of the respiratory system were investigated. Each manoeuvre produced many hundreds of droplets of a range of size, the vast majority being less than 1mm diameter. Droplets under 1mm dia. travelled over 1m - much further than could be expected if their flight was ballistic, like that of impact spatter. Respired blood aerosol properties are explained in terms of established mechanics of airflow shear induced aerosol production and the fluid mechanics of exhaled air movement. 相似文献
272.
Chen T Catcheside DE Stephenson A Hefford C Kirkbride KP Burgoyne LA 《Journal of forensic sciences》2012,57(2):472-477
Abstract: This paper reports the results of a commission to develop a field deployable rapid short tandem repeat (STR)‐based DNA profiling system to enable discrimination between tissues derived from a small number of individuals. Speed was achieved by truncation of sample preparation and field deployability by use of an Agilent 2100 BioanalyserTM. Human blood and tissues were stabbed with heated stainless steel wire and the resulting sample dehydrated with isopropanol prior to direct addition to a PCR. Choice of a polymerase tolerant of tissue residues and cycles of amplification appropriate for the amount of template expected yielded useful profiles with a custom‐designed quintuplex primer set suitable for use with the BioanalyserTM. Samples stored on wires remained amplifiable for months, allowing their transportation unrefrigerated from remote locations to a laboratory for analysis using AmpFlSTR® Profiler Plus® without further processing. The field system meets the requirements for discrimination of samples from small sets and retains access to full STR profiling when required. 相似文献
273.
Social Dominance Orientation, one of the most popular individual differences measures in the study of generalized prejudice, can be understood as having two components: Opposition to Equality (OEQ) and support for Group-Based Dominance (GBD). We consider these components in terms of system justification theory and social identity theory. We find that each component best explains different kinds of political views, consistent with the theory that they arise from different motivations. OEQ reflects system justification motives. It better predicts attitudes towards redistributive social policy, political conservatism, and a lack of humanitarian compassion for the disadvantaged. GBD reflects social identity motives. It is more associated with hostility toward outgroups and concerns about intergroup competition. GBD and OEQ have different personality and demographic correlates, exhibit distinctive relations with explicit and implicit attitudinal preferences, and differentially predict a variety of policy attitudes. Use of GBD and OEQ as separate constructs enriches the understanding of prejudice, policy attitudes, and political ideology. 相似文献
274.
David R. Morello B.S. ; Sam D. Cooper B.S. ; Sini Panicker M.S. ; John F. Casale B.S. 《Journal of forensic sciences》2010,55(1):42-49
Abstract: The illicit manufacture of heroin results in the formation of trace level acidic and neutral impurities. These impurities are detectable in illicit heroin and provide valuable information about the manufacturing process used. The isolation, derivatization, and semiquantitative analysis of neutral and acidic heroin manufacturing impurities by programmed temperature vaporizing injector-gas chromatography-mass spectrometry (PTV-GC-MS) is described. Trace acidic and neutral heroin impurities were isolated from basic fractions using liquid–liquid extraction. Extracted impurities were treated with N -Methyl- N -trimethylsilyltrifluoroacetamide followed by PTV-GC-MS analyses. Semiquantitative data were obtained using full scan mass spectrometry utilizing unique ions or ion combinations for 36 trace impurities found in crude and/or highly refined heroin samples. Minimum detection limits for acidic and neutral impurities were estimated to be at the 10−7 level relative to total morphine. Over 500 authentic heroin samples from South America, Mexico, Southwest Asia, and Southeast Asia were analyzed. Classification of illicit heroin based on the presence or absence and relative amounts of acidic and neutral impurities is presented. 相似文献
275.
Benford's Law for Quality Assurance of Manner of Death Counts in Small and Large Databases 下载免费PDF全文
Jeremy Daniels M.D. Samantha‐Jo Caetano M.Sc. Dirk Huyer M.D. Andrew Stephen B.A. John Fernandes M.D.C.M. Alice Lytwyn M.D.C.M. Fred M. Hoppe Ph.D. 《Journal of forensic sciences》2017,62(5):1326-1331
To assess if Benford's law, a mathematical law used for quality assurance in accounting, can be applied as a quality assurance measure for the manner of death determination. We examined a regional forensic pathology service's monthly manner of death counts (N = 2352) from 2011 to 2013, and provincial monthly and weekly death counts from 2009 to 2013 (N = 81,831). We tested whether each dataset's leading digit followed Benford's law via the chi‐square test. For each database, we assessed whether number 1 was the most common leading digit. The manner of death counts first digit followed Benford's law in all the three datasets. Two of the three datasets had 1 as the most frequent leading digit. The manner of death data in this study showed qualities consistent with Benford's law. The law has potential as a quality assurance metric in the manner of death determination for both small and large databases. 相似文献
276.
277.
278.
279.
Alice Sindzingre 《Cambridge Review of International Affairs》2003,16(1):89-103
The article focuses on the microeconomic foundations and effects of the fragile tax base in Sub-Saharan Africa, which have been insufficiently taken into account by the international financial institutions. Two vicious circles are analysed. The first addresses the political economy of states: their inability to redistribute revenues reinforces a lack of credibility, leading to a reluctance by the majority of the population to pay taxes. Instead, there is ongoing reliance on private interpersonal transfers. This is compounded by the way markets interlock, creating negative effects in terms of efficiency. This vicious circle is related to a second one, which stems from the nature of the social contracts that link citizens to the state, and which are rarely of the individualistic-voluntary type characteristic of developed states. States, therefore, are often not part of the reciprocity chain, which explains the failure of some reforms in Africa. 相似文献
280.