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   286篇
  免费   15篇
各国政治   19篇
工人农民   12篇
世界政治   35篇
外交国际关系   27篇
法律   159篇
中国政治   4篇
政治理论   43篇
综合类   2篇
  2023年   3篇
  2022年   5篇
  2021年   6篇
  2020年   7篇
  2019年   8篇
  2018年   6篇
  2017年   12篇
  2016年   10篇
  2015年   12篇
  2014年   10篇
  2013年   49篇
  2012年   13篇
  2011年   15篇
  2010年   3篇
  2009年   8篇
  2008年   16篇
  2007年   21篇
  2006年   17篇
  2005年   15篇
  2004年   15篇
  2003年   12篇
  2002年   3篇
  2001年   3篇
  2000年   6篇
  1999年   2篇
  1998年   4篇
  1997年   5篇
  1996年   1篇
  1995年   2篇
  1994年   2篇
  1992年   1篇
  1990年   2篇
  1985年   1篇
  1984年   1篇
  1977年   2篇
  1975年   1篇
  1973年   1篇
  1968年   1篇
排序方式: 共有301条查询结果,搜索用时 15 毫秒
171.
Developing and implementing a generally accepted procedure for the dating of ink found on documents using dynamic approaches has been a very formidable undertaking by forensic document examiners. 2-Phenoxyethanol (PE), a common volatile organic compound found in ballpoint inks, has been recognized for over a decade as a solvent that evaporates as ink ages. More recently, investigations have focused on the solvent loss ratio of PE prior to and after heating. To determine how often PE occurs in ink formulations, the authors analyzed 633 ballpoint inks utilizing a gas chromatograph/mass spectrometer. 2-Phenoxyethanol was identified in 85% (237/279) and 83% (293/354) of black and blue inks, respectively.  相似文献   
172.
Haplotype, allele frequencies and population data of 17 Y-chromosome STR loci DYS19, DYS385, DYS389I, DYS389II, DYS390, DYS391, DYS392, DYS393, DYS437, DYS438, DYS439, DYS460 (GATA A7.1), DYS461 (GATA A7.2), GATA A10, GATA C4 and GATA H4 were determined from a sample of 148 unrelated male individuals from Spain. A total of 144 haplotypes were identified by the 17 Y-STR markers, of which 141 were unique, two were found in two individuals and one was found in three individuals. The haplotype diversity (99.95%) and discrimination capacity (97.30%) were calculated. Comparisons were made with previously published haplotype data on other Iberian population samples and no significant differences were found.  相似文献   
173.
174.
Age-related changes in tooth color have been described previously, however, the use of dental color for age estimation in forensic odontology has been limited due to the difficulty of measuring color objectively. This study presents an objective method for determining dental color to estimate the age of an individual. Dentine color in 250 teeth from patients ranging in age from 10 to 89 years was determined by spectroradiometry. Color measurements were performed as suggested in the CIE 1931 (International Commission on Illumination). Chromaticity coordinates (x, y, z), luminance (Y), whiteness index (WIC, Z%, WIC) and yellowness index (YI) were obtained. Correlations between these colorimetric variables and aging were established by linear regression analyses. All the variables fit the mathematical model with correlation coefficients ranging from 0.53 to 0.75. This method of color measurement produced an expected associated error of calibration averaging 13.7 years about the mean estimated values, at a 70% level of confidence. Two different multiple regression models for dental age estimation were tested, and variables that made the greatest contributions to age calculation were identified. To determine the effect of postmortem interval on tooth color and its influence in age estimation, 37 teeth obtained from human skeletal remains buried during an interval ranging from 21 to 37 years were also studied. In this material, the correlation between age and dental color measured by spectroradiometry was weaker than in fresh extracted teeth.It is concluded that determination of dentine color by spectroradiometry is a potentially useful objective method to estimate age in forensic studies in combination with other methods.  相似文献   
175.
We report the results of Spanish and Portuguese working group (GEP) of International Society of Forensic Genetics (ISFG) Collaborative Exercise 2001-2002 on mitochondrial DNA (mtDNA) analysis. 64 laboratories from Spain, Portugal and several Latin-American countries participated in this quality control exercise. Five samples were sent to the participating laboratories, four blood stains (M1-M4) and a sample (M5) consisting of two hair shaft fragments. M4 was non-human (Felis catus) in origin; therefore, the capacity of the labs to identify the biological source of this sample was an integral part of the exercise. Some labs detected the non-human origin of M4 by carrying out immuno-diffussion techniques using antihuman serum, whereas others identified the specific animal origin by testing the sample against a set of animal antibodies or by means of the analysis of mtDNA regions (Cyt-b, 12S, and 16S genes). The results of the other three human blood stains (M1-M3) improved in relation to the last Collaborative Exercises but those related to hairs yielded a low rate of success which clearly contrasts with previous results. As a consequence of this, some labs performed additional analysis showing that the origin of this low efficiency was not the presence of inhibitors, but the low quantity of DNA present in these specific hair samples and the degradation.As a general conclusion the results emphasize the need of external proficiency testing as part of the accreditation procedure for the labs performing mtDNA analysis in forensic casework.  相似文献   
176.
In recent years, numerous Latin–American countries have carried out reforms in their public accounting systems, with technical cooperation provided by the U.S. Agency for International Development (USAID). Taking into account the lack of international accounting standards for the public sector, USAID has designed a model termed Integrated Financial Management System for Latin America and the Caribbean (IFMS or SIMAFAL). This model is intended to provide better financial information for governmental decision‐taking as regards the allocation of resources; a further goal is to achieve greater transparency and for a higher degree of responsibility to be accepted for the commitments made and the results of activities undertaken. Important changes are currently taking place on the international public accounting scene and the International Federation of Accountants (IFAC) is pressing for the adoption of a set of international public accounting standards by Latin–American countries. In this article, we compare the level of information included in the year‐end governmental public report in Latin–American countries which have carried out their reforms outside SIMAFAL with that of others which have followed this model. Second, we examine the extent to which the public financial reporting practices recommended by IFAC coincide with those adopted by the above countries. Copyright © 2007 John Wiley & Sons, Ltd.  相似文献   
177.
The need to implement novel techniques, able to support a causal link between exposure and pathology, has been emerged over the recent years. The application of scanning electron microscope coupled with probe X‐ray microanalysis (by means of an energy‐dispersive spectroscopy) has been developed by our research group for the bone remains investigation. It was aimed to testify the exposure to microsized and nanosized pollutions, due to military activities in the Quirra interforce firing range, of a Sardinian shepherd, died of acute leukemia. Metallic debris with a combustive morphology and with an oncogenic potential has been surely detected inside his bone marrow canal. This novel technique has proved to be able to bring to light a source of past exposure preserved over time within the bone marrow canal. It can be useful for postmortem analyses, delivering a new avant‐garde approach to modern forensic science.  相似文献   
178.
The sequences of the two hypervariable (HV) segments of the mitochondrial DNA (mtDNA) control region were determined in 167 randomly selected, unrelated individuals living in the state of Alagoas, north-eastern Brazil. One hundred and forty-five different haplotypes, associated with 139 variable positions, were determined. More than 95% of the mtDNA sequences could be allocated to specific mtDNA haplogroups according to the mutational motifs. Length heteroplasmy in the C-stretch HV1 and HV2 regions was observed in 22 and 11%, respectively, of the population sample. The genetic diversity was estimated to be 0.9975 and the probability of two random individuals presenting identical mtDNA haplotypes was 0.0084. The most frequent haplotype was shared by six individuals. All sequences showed high-quality values and phantom mutations were not detected. The diversity revealed in the mitochondrial control region indicates the importance of this locus for forensic casework and population studies within Alagoas, Brazil.  相似文献   
179.
180.
This paper studies the relationship between self-reported crime victimization, perceptions of corruption, and attitudes of Mexico’s armed forces. We find that perceptions of corruption along with individual and state-level factors are important predictors of support for Mexico’s Army and Navy. While crime and violence have had a tremendous impact on Mexican society, crime victimization does not seem to undermine public support for the armed forces. In contrast, corruption in these institutions does undermine support. Given the historical and contemporary significance of the armed forces, this research has significant implications for the role of the coercive apparatus of the Mexican state.  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