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   1015篇
  免费   90篇
各国政治   108篇
工人农民   67篇
世界政治   120篇
外交国际关系   55篇
法律   582篇
中国政治   3篇
政治理论   169篇
综合类   1篇
  2023年   19篇
  2022年   6篇
  2021年   29篇
  2020年   34篇
  2019年   41篇
  2018年   71篇
  2017年   93篇
  2016年   58篇
  2015年   56篇
  2014年   57篇
  2013年   160篇
  2012年   51篇
  2011年   47篇
  2010年   20篇
  2009年   11篇
  2008年   42篇
  2007年   35篇
  2006年   36篇
  2005年   35篇
  2004年   42篇
  2003年   48篇
  2002年   34篇
  2001年   20篇
  2000年   13篇
  1999年   7篇
  1998年   6篇
  1997年   6篇
  1996年   1篇
  1995年   2篇
  1994年   1篇
  1993年   2篇
  1992年   2篇
  1991年   4篇
  1990年   1篇
  1989年   1篇
  1988年   3篇
  1984年   1篇
  1983年   1篇
  1978年   1篇
  1976年   1篇
  1972年   2篇
  1970年   1篇
  1968年   1篇
  1967年   1篇
  1966年   1篇
  1964年   1篇
排序方式: 共有1105条查询结果,搜索用时 31 毫秒
1.
Journal of Youth and Adolescence - Previous research analyzing the differences in physical fitness and body composition between active and sedentary adolescents aged 12–16 has not provided...  相似文献   
2.
This paper aims to analyse whether illegal (corruption) and legal rent extraction (high politicians’ wages) affect electoral outcomes at municipal level. We use an initial sample of 145 Spanish municipalities over 50,000 for two electoral periods: 2004–2007 (before the crisis) and 2008–2011 (during the crisis). Our findings show that neither illegal nor legal rent extraction impact on re-election in non-crisis times. However, we observe that citizens penalize legal rent extraction in the ballots during the crisis. Regarding the economic performance of the local governments, we find that its effect on re-election is important in non-crisis period. Nevertheless, in time of crisis, given that the economic situation is bad in general in the country, voters pay less attention to economic factors and focus on politicians’ behaviour.  相似文献   
3.
Innovating upon previous field experiments and theories of identity‐based discrimination, we test whether public officials are using searches (“identity‐questing”) to profile citizens and acting on latent biases. Pairs of “institutional” and “noninstitutional” requesters send lower and moderate burden freedom of information (FOI) requests—providing no identity cues apart from undistinctive names, e‐mails, and ID numbers—to nearly 700 of Brazil's largest municipalities. Results show institutional requesters receive one‐fifth more responses than noninstitutional comparators. For moderate versus lower burden requests, noninstitutional requesters are 11% less likely to receive a compliant response than their institutional comparators. The only plausible explanation for these results is identity‐questing, a phenomenon that has far‐reaching policy implications. Most of the world's FOI laws, for example, contain vague ID obligations, which translate incoherently from laws to regulation and practice. Results enjoin public service providers to protect the identities of citizens by default or upon request.  相似文献   
4.
We analysed the Chilean university student selection processes, comparing ‘First Generation’ and ‘Continuist’ students, using the Chilean Higher Education population databases (2000–2015). Findings confirm that 60 percent of participants in the selection process are First Generation students. The data registers an increasing self-exclusion phenomenon. Of the students who did not take the selection test after enrolling, 80 percent are First Generation and 18 are enrolled in a selective university, compared to 44 in the Continuist conglomerate. These differences may be explained by cultural capital in the Bourdieu sense, in conjunction with a diversified, massified and marketalised higher education system.  相似文献   
5.
ABSTRACT

Studies have shown that long-lived individuals seem to pass their survival advantage on to their offspring. Offspring of long-lived parents had a lifelong survival advantage over individuals without long-lived parents, making them more likely to become long-lived themselves. We test whether the survival advantage enjoyed by offspring of long-lived individuals is explained by environmental factors. 101,577 individuals from 16,905 families in the 1812–1886 Zeeland cohort were followed over time. To prevent that certain families were overrepresented in our data, disjoint family trees were selected. Offspring was included if the age at death of both parents was known. Our analyses show that multiple familial resources are associated with survival within the first 5 years of life, with stronger maternal than paternal effects. However, between ages 5 and 100 both parents contribute equally to offspring’s survival chances. After age 5, offspring of long-lived fathers and long-lived mothers had a 16-19% lower chance of dying at any given point in time than individuals without long-lived parents. This survival advantage is most likely genetic in nature, as it could not be explained by other, tested familial resources and is transmitted equally by fathers and mothers.  相似文献   
6.
Ammonium nitrate fuel oil is an explosive mixture found in most antipersonnel landmines (APL) buried throughout the Colombian territory. During more than 50 years of internal conflict, the Colombian government has found that trained dogs are the most effective method to detect APL. However, the olfactive signature in ANFO is unknown and also if there are differences in detection related to the explosive manufacturing origin. Therefore, this work begins with the analytical validation of the method used to determine ammonia, in its derivatized form as carbamate, released by home-made ANFO using HS-SPME-GC-FID. Once validated, the method was used to identify ammonia and other organic volatile compounds present in ANFO, under laboratory and simulated field conditions. The validation process includes the evaluation of the optimum conditions for the derivation and extraction of butylcarbamate, the determination of the working ranges with linear response in FID, the limits of detection and quantification, the sensitivity, and the precision. The results of the validation established linearity and sensitivity in a concentration between 20 and 120 mg/L, as well as low limits of detection and quantification of 6.4 and 21.4 mg/L, respectively. Also, an intermediate precision of 11% for butylcarbamate with a repeatability of 8%. The validated method showed in real samples of home-made ANFO besides ammonia, the presence of low molecular methylamines, and also exhibited differences in volatile compositions according to the origin. The objective of this work is to offer a reliable analytical methodology for the extraction and analysis of volatile compounds from ANFO.  相似文献   
7.
Prediction facial features from the skull are recurring theme on the forensic literature. The nose has been investigated since it has a significant role in facial recognition and the literature shows that there is not an universal method for nasal prediction. This study aimed to conduct a systematic review to analyze what are the most consistent techniques of nasal reconstruction. Primary studies describing or validating nasal reconstruction techniques in adults and published in journals of Forensic Sciences were included in this review. Tedeschi‐Oliveira's method positioned nasal tip with acceptable accuracy as Gerasimov's method. The Krogman's and Iscan's technique underestimated nasal projection in North Americans. The Prokopec's and Ubelaker's method obtained accuracy in Caucasoid. George's method presented results similar to reference standard in Caucasoid. In a supplementary way, studies are needed to accurately estimate the nasal width.  相似文献   
8.
ABSTRACT

In local government systems worldwide, financial pressures have obliged local authorities to focus on cost-efficient methods for providing local services, including inter-municipal agreements and public–public partnerships. However, in comparison with municipal mergers, privatisation and other approaches to the problem, the cost impact of the cooperative provision has not yet been thoroughly examined empirically. Moreover, available empirical research has largely concentrated on waste disposal in developed countries. The present paper seeks to contribute to the empirical literature on inter-municipal agreements and public–public partnerships by comparing their impact on costs with ‘stand-alone’ provision in a range of non-waste local services. In contrast to the bulk of existing studies, our analysis takes place in a developing country context by examining Brazilian local government over the period 2013/15. We found that – on the whole – cooperative provision is less expensive than the ‘stand-alone’ provision for the services studied. Our results can be explained by the size and composition of the population, together with the politics for cooperation.  相似文献   
9.
The secondary dentin deposition that occurs after the tooth formation process results in a decrease in pulp cavity volume in adolescents and adults. The purpose of this critical review was to correlate pulpal and/or dental volume on cone-beam computed tomography (CBCT) with chronological age approximation. A subobjective was to investigate which methodology and CBCT technical parameters would be most appropriate to evaluate this correlation. This critical review followed the PRISMA guidelines, and it was conducted by a search through PubMed, Embase, SciELO, Scopus, Web of Science, Cochrane Library databases, as well as gray literature. Primary studies that used pulp volume, or pulp chamber to tooth volume ratio measured using CBCT were included. Seven hundred and eight indexed and 31 non-indexed records were identified. A qualitative analysis was performed including 25 selected studies with a total of 5100 individuals, age ranging from 8 to 87 years without sex predilection. The most used method was pulp volume/tooth volume. CBCT voxel size ranged between 0.09 and 0.5. Manual segmentation associated with threshold algorithms was used in most of the studies. Correlation between the pulp volume/tooth volume ratio was moderate: −0.66 for the upper central incisors, −0.59 for upper canines and −0.56 for lower canines. High heterogeneity was observed among the studies. It is concluded that pulp volume should be used with caution in age estimation. Evidence supports the preferable use of upper incisors with pulp volume/tooth volume ratio for age estimation. There is not enough evidence that voxel size interferes in age estimation by pulp volume.  相似文献   
10.
The true impact of heat-induced changes in human bone regarding their sex estimation has not been comprehensively documented having a potentially negative impact on forensic anthropology. The objective of this paper was to evaluate how heat exposure affects sex estimation based on both morphological and metric features. The study focused in both low-to-medium intensity burns and high intensity burns. Selected sexually dimorphic features were analysed in 51 experimentally burnt skeletons from the 21st Century Identified Skeletal Collection. Bones were burnt to maximum temperatures between 450 °C and 1050 °C achieved after 75 to 257 min. Morphological methods tested in this study comprised the recommendations for hipbone features from Buikstra and Ubelaker (1994) and from Bruzek (2002). On the other hand, metric references tested here were the ones from Wasterlain (2000), Curate et al. (2016) and Gonçalves et al. (2013) focused on the humerus, femur, calcaneus and talus. Agreement was tested with Gwet’s AC1 test and was further assessed by calculating the relative amount of perfect agreements. Results demonstrated that heat-induced changes affected not only the scoring of morphological features burnt at high temperatures but also the scoring of features burnt at lower intensities. On the other hand, metric features were only considerably affected in high intensity burns, no major changes being documented for low-to-medium intensity burns. For low-to-medium intensity burns, the Bruzek and Curate et al. methods revealed a better agreement between the pre- and post-burning scores. For high intensity burns, better agreement was obtained by using the Bruzek (2002) and Gonçalves et al. (2013) methods. As expected, heat-induced warping, fracture and metric change had a major impact on the pre- and post-observations’ agreement. Contrary to what has been systematically assumed over the years, this impact is also quite substantial in bones burnt at low-to-medium burn intensities so caution is advised during the analysis of this kind of burnt skeletal material.  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