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   12825篇
  免费   118篇
各国政治   469篇
工人农民   453篇
世界政治   973篇
外交国际关系   511篇
法律   8088篇
中国政治   91篇
政治理论   2306篇
综合类   52篇
  2020年   158篇
  2019年   225篇
  2018年   257篇
  2017年   272篇
  2016年   278篇
  2015年   190篇
  2014年   280篇
  2013年   1213篇
  2012年   311篇
  2011年   346篇
  2010年   277篇
  2009年   294篇
  2008年   344篇
  2007年   359篇
  2006年   347篇
  2005年   302篇
  2004年   333篇
  2003年   319篇
  2002年   261篇
  2001年   584篇
  2000年   539篇
  1999年   392篇
  1998年   167篇
  1997年   154篇
  1996年   131篇
  1995年   123篇
  1994年   124篇
  1993年   99篇
  1992年   249篇
  1991年   274篇
  1990年   258篇
  1989年   270篇
  1988年   238篇
  1987年   255篇
  1986年   226篇
  1985年   240篇
  1984年   205篇
  1983年   202篇
  1982年   133篇
  1981年   149篇
  1980年   98篇
  1979年   162篇
  1978年   113篇
  1977年   90篇
  1976年   81篇
  1975年   84篇
  1974年   106篇
  1973年   111篇
  1972年   80篇
  1971年   85篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
931.
A 53-year-old woman who was diagnosed as suffering from depression was found dead in her bed. The autopsy revealed no morphological changes sufficient to explain death. Toxicological analysis was performed and the drugs trimipramine (2.33 mg/l), citalopram (4.81 mg/l) and zolpidem (0.07 mg/l) were identified in the femoral blood. A combined drug intoxication resulting in synergistic effects to cardiovascular disorders was proposed as the cause of death. An acute overdose and suicide was suggested by calculation of the parent drug to main metabolite ratios in femoral blood and liver tissue. The trimipramine to desmethyltrimipramine ratios were calculated to be 2.06 and 3.18, the citalopram to desmethylcitalopram ratios were 1.96 and 2.02.  相似文献   
932.
The U.S. Census Bureau recently released new, experimental measures of poverty based on a National Academy of Sciences (NAS) panel's recommendations. This article examines the effects of the experimental measures on poverty rates among persons aged 65 or older in order to help inform policy debate. Policymakers and analysts use poverty rates to measure the successes and failures of existing programs and to create and defend new policy initiatives. The Census Bureau computes the official rates of poverty using poverty thresholds and definitions of countable income that have changed little since the official poverty measure was adopted in 1965. Amid growing concerns about the adequacy of the official poverty measure, a NAS panel undertook a study of the concepts, methodology, and data needed to measure poverty. The panel concluded in its 1995 report that the current measure no longer provides an accurate picture of relative rates of poverty for different groups in the population or of changes in poverty over time. The panel recommended changes in establishing the poverty thresholds, defining family resources, and obtaining the required data. The Census Bureau report shows how estimated levels of poverty would differ from the official level as specific recommendations of the NAS panel are implemented individually and how estimated trends would differ when many recommendations are implemented simultaneously. It computes nonstandardized and standardized poverty rates. (The latter constrains the overall poverty rate under the experimental measures to match the official rate.) This article reports poverty rates that have not been standardized and provides considerably more detail than the Census report about the effects of the experimental measures on poverty among the aged. It examines the effects of changing the poverty thresholds and the items included or excluded from the definition of available resources. It also explores the effects of the experimental measures on persons aged 65 or older by age group, gender, race and ethnicity, and marital status. Results indicate that: Poverty rates in 1997 for persons aged 65 or older under the experimental NAS poverty measure are 17.3 percent, compared with 10.5 percent under the official poverty measure. This 65-percent increase is largely driven by the NAS-based measure's subtraction of medical out-of-pocket (MOOP) expenses from resources. Under the NAS-based measures, poverty rates increase for all major groups of older persons, and increase the most for groups for whom the incidence of official poverty is the lowest. The experimental NAS poverty measure shows narrower differences between genders, racial and ethnic groups, and among persons of different marital statuses than the official poverty measure. For example, white Hispanic women aged 65 or older have poverty rates that are 450 percent higher than those for white non-Hispanic men under the official poverty measure and 181 percent higher under the NAS measure. The NAS-based measure's subtraction of MOOP expenses from resources has a disproportionate effect on poverty rates among non-Hispanic whites and men as compared with other groups. However, changes in relative poverty between groups appear to be most influenced by the NAS midpoint equivalence scale. Because this scale decreases poverty rates for persons who live alone or with unrelated individuals and increases them for persons who live with others, poverty rates differ meaningfully under the NAS and official measures among demographic groups. This article highlights issues concerning the elements of the experimental NAS poverty measure that are particularly important to the measurement of poverty among the aged population. Results suggest that the research community's future efforts to refine, enhance, and build upon the NAS panel's recommendations will yield important insights about poverty among the older population.  相似文献   
933.
Kübler  Dorothea 《Public Choice》1999,101(1-2):85-107
In response to the analysis of bureaucracies and the finding of inherent inefficiencies, public choice theory argues for an increase in competition by contracting out government services and deregulation. The paper explores the effect of coexisting public and private employment services in a model with private information of the worker about her ability and unobservable effort choice. The employer's use of an efficient unemployment exchange and an efficient private agency may lead to optimal screening with first best contracts. This is due to the assumption that good types of workers lose more human capital than bad types in periods of unemployment or mismatch. In contrast to standard screening contracts, a bad type of worker earns an information rent if the employment exchange is inefficient, but the employer chooses not to use the private agency for good types.  相似文献   
934.
Dow  Jay K. 《Political Behavior》1999,21(4):305-324
This study estimates a model of voter choice for the first and second ballots of the 1995 French Presidential election. Its objective is to characterize the relative importance of traditional bases of French voter choice such as social class relative to campaign issues and voter evaluations of the economy. The study also seeks to identify candidate-specific bases of voter choice. Multinomial logit analysis of voter choice among the four leading candidates reveals a stronger role for campaign issues than previous studies suggest. Voter-candidate ideological proximity is the strongest predictor of first and second ballot choice, followed by voter perceptions of candidate ability to address unemployment and political corruption. Demographic variables have limited explanatory power in both the first and second ballot models. The parameter estimates demonstrate considerable differences in the bases of voter choice across candidates, with the bases of voter choice for National Front leader Jean-Marie le Pen most distinct from those of the remaining candidates.  相似文献   
935.
936.
937.
Calculation of age from fetal and newborn remains may be problematic, and when these remains are altered by maceration, decomposition or burning, age may be more difficult to discern. When soft tissue indicators are transformed, then two techniques exist for accurate age determination; dental development, which may prove difficult given the degree of tissue alteration; and appearance, size and fusion of ossification centers, including diaphyseal length, which may yield inaccurate ages if shrinkage is not accounted for. This study is undertaken to facilitate age calculation by systematically re-evaluating diaphyseal shrinkage and determine shrinkage rates from wet to carbonized states and wet to calcined states using Petersohn and K?hler's data, originally published in German and then published in Fazekas and Kósa (1978:362-369). Average shrinkage, standard deviation, minimum and maximum values are calculated for each diaphysis and then for all diaphyses between 4-10 lunar months (LM) and for newborns. Associated values for carbonized diaphyses are: 4 LM--32.50% +/- 12.12%; 5 LM--14.04% +/- 4.44%; 6 LM--6.78% +/- 1.06%; 7 LM--4.18% +/- 0.31%; 8 LM--3.47% +/- 0.42%; 9 LM--3.05% +/- 0.18%; 10 LM--2.46% +/- 0.67%; and in newborns 2.16% +/- 0.29%. Similar values for calcined diaphyses are: 4 LM--40.11% +/- 17.51%; 5 LM--18.29% +/- 4.42%; 6 LM--9.84% +/- 1.27%; 7 LM--9.82% +/- 0.51%; 8 LM--9.42% +/- 0.72%; 9 LM--9.45% +/- 0.33%; 10 LM--8.94% +/- 0.37%; and in newborns 8.96% +/- 0.49%. These findings suggest that percent shrinkage due to carbonization and calcination is greatest in the earliest age groups, decreasing substantially with advancing age. The rates of shrinkage, however, vary by the burning process utilized and age group studied. These general findings are similar to those of Petersohn and K?hler, yet specific values for percent shrinkage vary greatly from values cited in this analysis. These data provide a means to assess the degree of shrinkage that occurs for each diaphysis for each given age group.  相似文献   
938.
Electrospray ionization (ESI) and matrix-assisted laser desorption/ionization (MALDI) mass spectrometry have been used to examine evidence in a sexual assault investigation. Because condoms are being used increasingly by sexual assailants and some condom brands include the spermicide nonoxynol-9 (nonylphenoxy polyethoxyethanol) in the lubricant formulation, the recovery, and identification of nonoxynol-9 from evidence items may assist in proving corpus delicti. A method was developed for the recovery of nonoxynol-9 from internal vaginal swabs and for its identification by reverse phase liquid chromatography/electrospray ionization mass spectrometry (LC ESI-MS), nanoelectrospray ionization (nanoESI) mass spectrometry, and high resolution MALDI Fourier transform mass spectrometry (MALDI-FTMS). The method was tested on extracts from precoitus, immediate postcoitus, and four-hours postcoitus vaginal swabs provided by a volunteer whose partner does not normally use condoms, but for this trial used a condom having a water-soluble gel-type lubricant that includes 5% nonoxynol-9 in its formulation. Subsequently, LC ESI-MS was used to identify traces of nonoxynol-9 from the internal vaginal swab of a victim of a sexual assault.  相似文献   
939.
In order to use genetic loci in forensic identity testing, some population data are needed. This paper presents a report of allele frequency data for the loci HUMTH01, HUMTPOX and HUMVWA in a population sample from Northern Spain. No deviation from the Hardy-Weinberg equilibrium was detected in any of the three markers investigated and there was no evidence of association between the alleles of these loci. Statistical analysis was also carried out to obtain some parameters of medicolegal interest and comparative studies were carried out with other populations studied to date for these five loci. The Asturian sample does not differ substantially from other Caucasian and Spanish populations.  相似文献   
940.
No reliable data are available on cases of lethal child abuse (by active force) in the area of the former German Democratic Republic. In a multicenter study we therefore examined the police and court records for such cases occurring in the period 1 January 1985 to 2 October 1990 in the entire area of the former German Democratic Republic. RESULTS: The study center received information on 39 cases of lethal child abuse which correspond to approximately 7 cases per year. However, a low percentage of undetected crimes which cannot be determined more precisely has to be taken into consideration. Almost 40% of the victims were younger than 1 year, 73% of the victims showed indications of repeated ill-treatment. The effects caused by using direct blunt forces, against the head in particular, were by far the most frequent causes of death. The male contact person (the victim's father, brother or stepfather as well as the life companion of the child's mother in particular) killed the child in most of the cases. As far as it is known, 37% of the male/female offenders suffered from chronic alcoholism; 32% of the male/female offenders were under the influence of alcohol when the crime happened. 83% of the male/female offenders who were found guilty made a confession shortly after the crime had happened or during the interrogations. Almost all the male/female offenders were sentenced to prison (the duration of the imprisonment varied between one year and for life). Due to the considerably lower section rate compared to the one in the German Democratic Republic, it is to fear that each second fatal child abuse is not detected in the new federal states.  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