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   861篇
  免费   22篇
各国政治   45篇
工人农民   52篇
世界政治   124篇
外交国际关系   54篇
法律   407篇
中国政治   4篇
政治理论   193篇
综合类   4篇
  2022年   3篇
  2021年   9篇
  2020年   13篇
  2019年   32篇
  2018年   32篇
  2017年   41篇
  2016年   36篇
  2015年   23篇
  2014年   21篇
  2013年   144篇
  2012年   25篇
  2011年   30篇
  2010年   16篇
  2009年   20篇
  2008年   29篇
  2007年   31篇
  2006年   37篇
  2005年   33篇
  2004年   17篇
  2003年   28篇
  2002年   23篇
  2001年   16篇
  2000年   16篇
  1999年   11篇
  1998年   17篇
  1997年   14篇
  1996年   9篇
  1995年   9篇
  1994年   11篇
  1993年   12篇
  1992年   10篇
  1991年   5篇
  1990年   8篇
  1989年   10篇
  1988年   4篇
  1987年   5篇
  1986年   5篇
  1985年   6篇
  1984年   7篇
  1983年   3篇
  1982年   12篇
  1981年   7篇
  1980年   4篇
  1979年   3篇
  1978年   5篇
  1977年   5篇
  1976年   4篇
  1973年   3篇
  1971年   3篇
  1967年   3篇
排序方式: 共有883条查询结果,搜索用时 46 毫秒
51.
A method for comparison of the relative age of ink entries written by the same ballpoint pen on documents stored in darkness is presented. Inks were extracted from the document and analyzed by HPLC (high performance liquid chromatography). On aging, changes in the chemical composition of the inks were noted. These changes were similar to those observed when inks were exposed to light or heat. The aging was followed by using ternary diagrams constructed for dyes generally present in blue-colored inks--Crystal Violet, Methyl Violet, and Tetramethyl Para Rosaniline. The procedure is applicable for relative dating of ink entries in diaries, notebooks, etc., where often several ink entries are written by the same ink. However, a prolonged exposure of the document to daylight and/or artificial light (light from fluorescent tubes) as well as to extensive heat will render the whole procedure inapplicable. An example of the use of the proposed method in casework is given.  相似文献   
52.
Self-report questionnaires are frequently used in youth research, but doubt remains whether total anonymity affects the results. This study compared the responses of 704 mainly 16–17-year-old adolescents to self-report measures of various health indicators in 2 groups: anonymous and confidential collection. For most health indicators no significant differences were found. Perceived health, use of alcohol, and aggressive behavior (for boys) were reported significantly less frequently in the confidential group (small effect size). It appeared that pupils with high scores on social desirability do not respond differently at most health indicators in the 2 conditions. For most health characteristics, epidemiologically useful outcomes may be derived from confidential self-report measures, which are also valuable for detecting individual at-risk children. Similar studies in lower grades and other types of education should confirm the results.Youth Department, Municipal Health Service Rotterdam area. Main research interests are emotional and behavioral problems of adolescents, youth health care, monitoring.Youth Department, Municipal Health Service Rotterdam area. Main research interests are emotional and behavioral problems of adolescents, youth health care, monitoring.Research Department, Municipal Health Service Rotterdam area. Major research interests include emotional and behavioral problems of adolescents, suicidal behavior, youth health care, monitoring.  相似文献   
53.
54.
This study uses a Policy Delphi to discern differences in perspective among and within groups responsible for formulating and implementing vocational rehabilitation policy. Four groups of players were chosen for our analysis: government officials, academics, directors of rehabilitation centers, and the staff who interface with program participants. Significant differences were found between the groups regarding the relative importance of possible legislative goals. This suggests that the failure of vocational rehabilitation policy to promote a work agenda may be attributed to a lack of consensus among policy implementors. The Delphi technique could help policy planners understand the different perspectives within the implementation community, and hence craft more realistic legislation.  相似文献   
55.
This article examines the relationship between conservative Protestant doctrine and economic policy attitudes. Building upon Weber's (1930) classic (and controversial) thesis that Calvinist thought inspired the capitalist spirit, we posit that the individualistic theology of fundamentalists, evangelicals, and charismatics often engenders political preferences for individualistic economic policies. We test this hypothesis by (1) performing a series of cross-sectional ordered probit analyses to understand the independent degree of association between doctrinal belief and economic attitudes toward taxing, spending, and the role of government, (2) creating and testing a structural equation model to assess various hypothesized paths of influence, and finally, (3) using 1994–96 NES panel data to assess the degree to which changes in an individual's doctrinal beliefs produce changes in his or her economic attitudes. Results lend substantial support to the efficacy of Weber's thesis, and point to religious belief as one exogenous agent of core political values.  相似文献   
56.
57.
Degradation of human DNA extracted from forensic stains is, in most cases, the result of a natural process due to the exposure of the stain samples to the environment. Experiences with degraded DNA from casework samples show that every sample may exhibit different properties in this respect, and that it is difficult to systematically assess the performance of routinely used typing systems for the analysis of degraded DNA samples. Using a batch of artificially degraded DNA with an average fragment size of approx. 200 bp a collaborative exercise was carried out among 38 forensic laboratories from 17 European countries. The results were assessed according to correct allele detection, peak height and balance as well as the occurrence of artefacts. A number of common problems were identified based on these results such as strong peak imbalance in heterozygous genotypes for the larger short tandem repeat (STR) fragments after increased PCR cycle numbers, artefact signals and allelic drop-out. Based on the observations, strategies are discussed to overcome these problems. The strategies include careful balancing of the amount of template DNA and the PCR cycle numbers, the reaction volume and the amount of Taq polymerase. Furthermore, a careful evaluation of the results of the fragment analysis and of automated allele calling is necessary to identify the correct alleles and avoid artefacts.  相似文献   
58.
The Y-PLEX 12 system, developed for use in human identification, enables simultaneous amplification of eleven polymorphic short tandem repeat (STR) loci, namely DYS392, DYS390, DYS385 a/b, DYS393, DYS389I, DYS391, DYS389II, DYS 19, DYS439 and DYS438, residing on the Y chromosome and Amelogenin. Amelogenin provides results for gender identification and serves as internal control for PCR. The validation studies were performed according to the DNA Advisory Board's (DAB) Quality Assurance Standards. The minimal sensitivity of the Y-PLEX 12 system was 0.1 ng of male DNA. The mean stutter values ranged between 3.76-15.72%. A full male profile was observed in mixture samples containing 0.5 ng of male DNA and up to 400 ng of female DNA. Amelogenin did not adversely affect the amplification of Y-STRs in mixture samples containing male and female DNA. The primers for the Y-STR loci present in Y-PLEX 12 are specific for human DNA and some higher primates. None of the primate samples tested provided a complete profile at all 11 Y-STR loci amplified with the Y-PLEX 12 system. Y-PLEX 12 is a sensitive, valid, reliable, and robust multiplex system for forensic analysis, and it can be used in human forensic and male lineage identification cases.  相似文献   
59.
The amphetamine derivative 3,4-methylenedioxymethamphetamine (MDMA, "Ecstasy" is a currently used or abused designer drug and fatalities are frequently encountered in forensic practice. However, the question remains open whether an MDMA blood level can be toxic or even potentially lethal. In order to provide insight in the interpretation of a detected MDMA concentration, the distribution of MDMA and its metabolite 3,4-methylenedioxyamphetamine (MDA) in various body fluids and tissues was studied and discussed in two different fatalities. Apart from peripheral blood samples (such as femoral and subclavian blood), various blood samples obtained centrally in the human body and several body fluids (such as vitreous humour) were examined. In addition, various tissues such as cardiac muscle, lungs, liver, kidneys, and brain lobes were analysed. In contrast to the peripheral blood levels, high MDMA and MDA levels were found in cardiac blood and the majority of the organs, except for the abdominal adipose tissue. The high concentrations observed in all lung lobes, the liver and stomach contents indicate that post-mortem redistribution of MDMA and MDA into cardiac blood can occur and, as a result, blood sampled centrally in the body should be avoided. Therefore, our data confirm that peripheral blood sampling remains "the golden standard". In addition, a distinct difference in peripheral blood MDMA concentrations in our two overdose cases was established (namely 0.271 and 13.508 microg/ml, respectively). Furthermore, our results suggest that, if a peripheral blood sample is not available and when putrefaction is not too pronounced, vitreous humour and iliopsoas muscle can be valuable specimens for toxicological analysis. Finally, referring to the various mechanisms of death following amphetamine intake, which can result in different survival times (e.g. cardiopulmonary complications versus hyperthermia), the anatomo-pathological findings and the toxicological results should be considered as a whole in arriving at a conclusion.  相似文献   
60.
Devising new incentives was a main element of health care reform in Israel, which created a regulated market that embodies many principles of managed competition. This study examined sick fund directors' perceptions of the new incentives and their strategic responses to these incentives, enabling the testing of how managed competition works in practice. The methodology used was a multiple case study of Israel's four sick funds. Data were gathered through in-depth interviews with 160 senior officials, analysis of national health insurance legislation, and analysis of published and unpublished archival documents, newspaper articles, public statements of senior managers, and other published data on the sick funds' behavior. The study revealed discrepancies between planned and perceived incentives and highlighted the effect of the latter on strategy formulation. Analysis of sick fund strategies showed that their responses to managed competition incentives deviated from theoretical expectations, compromising some of the objectives of the reform. The study also shows that contextual features account for the specific model of managed competition that was implemented and for the specific strategies employed by the sick funds. The study concludes by highlighting the need to build a process that will enable policy makers to consider local contextual factors when planning and implementing reform, involving health care providers in designing incentives, continuously monitoring processes and outcomes in the reformed system, and allowing for flexibility in policy making.  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