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   1726篇
  免费   66篇
各国政治   171篇
工人农民   86篇
世界政治   115篇
外交国际关系   108篇
法律   928篇
中国政治   7篇
政治理论   376篇
综合类   1篇
  2024年   2篇
  2023年   11篇
  2022年   15篇
  2021年   20篇
  2020年   42篇
  2019年   51篇
  2018年   88篇
  2017年   92篇
  2016年   84篇
  2015年   83篇
  2014年   67篇
  2013年   270篇
  2012年   128篇
  2011年   94篇
  2010年   55篇
  2009年   59篇
  2008年   77篇
  2007年   92篇
  2006年   52篇
  2005年   45篇
  2004年   43篇
  2003年   38篇
  2002年   39篇
  2001年   34篇
  2000年   35篇
  1999年   22篇
  1998年   13篇
  1997年   9篇
  1996年   15篇
  1995年   11篇
  1994年   4篇
  1993年   7篇
  1992年   7篇
  1991年   5篇
  1990年   6篇
  1989年   6篇
  1987年   4篇
  1986年   2篇
  1984年   7篇
  1983年   10篇
  1982年   8篇
  1981年   4篇
  1980年   5篇
  1979年   7篇
  1978年   7篇
  1977年   3篇
  1976年   2篇
  1967年   3篇
  1963年   1篇
  1962年   2篇
排序方式: 共有1792条查询结果,搜索用时 15 毫秒
901.
There are clear indicators that in spite of the sensitivity of internal security in terms of essential state functions and national sovereignty an EU governance framework with specific characteristics has emerged in the counter-terrorism field. Common threat assessments guide governance responses, and specific institutional structures, cooperation mechanisms, legal instruments, and forms of external action have been put into place to respond to the cross-border nature of the terrorist challenges. However, in line with the general subsidiary role only of the EU as provider of internal security in addition to the Member States, this governance framework remains based on the interaction and cooperation between national counter-terrorist systems and capabilities that remain largely under national control and still enjoy relatively wide margins of discretion in terms of priorities, legal framework, and organization. This analysis concludes that the EU's internal security governance – as evident from the counter-terrorism field – may be best characterized as an advanced institutionalized system of cooperation and coordination between national governance frameworks constructed around a core of common instruments and procedures with a cross-border reach.  相似文献   
902.
This article introduces a cross-cultural research project involving researchers from Bangkok, Thailand, and Vienna, Austria, and explores the effects of social network services (SNS) on practices of friendship initiation and relationship management among young adults. The focus of inquiry was on differences with regard to the organization of social networks, practices of friendship management, and the mutual interference between media and technology usage and lifestyles. On the basis of explorative interviews and group discussions with young adults living in the two cities studied, we developed a standardized online questionnaire to examine how participation in SNS, such as “Facebook” and “Hi5,” has an impact on the meaning of friendship. In addition, we analyzed ego-network structures and their implications for social integration.  相似文献   
903.
Neither absolute THC content nor morphology allows the unequivocal discrimination of fiber cultivars and drug strains of Cannabis sativa L. unequivocally. However, the CBD/THC ratio remains constant throughout the plant's life cycle, is independent of environmental factors, and considered to be controlled by a single locus (B) with two codominant alleles (BT and BD). The homozygous BT/BT genotype underlies the THC‐predominant phenotype, BD/BD is CBD predominant, and an intermediate phenotype is induced by the heterozygous state (BT/BD). Using PCR‐based markers in two segregating populations, we proved that the THCA synthase gene represents the postulated B locus and that specific sequence polymorphisms are absolutely linked either to the THC‐predominant or the THC‐intermediate chemotype. The absolute linkage provides an excellent reliability of the marker signal in forensic casework. For validation, the species‐specific marker system was applied to a large number of casework samples and fiber hemp cultivars.  相似文献   
904.
Bullying perpetration at school is a long-term predictor of aggression, delinquency, and violence. Most research concentrates on risk factors for such developments, whereas protective factors have been rarely addressed. Therefore, the present study investigates potentially protective effects of family and child characteristics in a prospective longitudinal design. The sample contained 519 youngsters (253 boys and 266 girls) from the Erlangen-Nuremberg Development and Prevention Study. Bullying perpetration was measured at age 9.0 years, mothers’ and children's reports on family and individual characteristics were collected at age 10.6, and outcomes in self-reported aggressive/violent offending and mother-reported aggressive and delinquent behavior were collected at age 13.7. Hierarchical regression analyses revealed main effects and interactions. The latter suggest buffering protective effects of consistent discipline in parenting and children's intelligence, positive attitude to school, prosocial behavior skills, low hyperactivity/inattention, and an anxious/depressive mood. The findings varied across the two outcome measures and with regard to gender. Implications for further research and prevention practice are discussed.  相似文献   
905.
906.
This article concerns whether and how political candidates adopt social media in their election campaigns. For campaigns, the openness and interactivity of social media tools bring about risks in terms of losing control over the message. Departing from a cost‐benefit perspective, this study addresses the question as to whether certain groups of candidates – differing in incumbency status, party type, gender, generation and urbanization level of the constituency – are more prone to adopt and utilize new social media tools and practices. In order to study how candidates approach social media in an early stage when the benefits are uncertain and the risks are apparent, candidate blogging in the 2007 Finnish national elections is examined. The findings show that the candidates generally were not ready to pursue the full potential of blogs and thereby to accept the risks associated with this open, interactive and personalized way of campaigning. Rather, the candidates took a cautious approach by not engaging extensively in the social media features and practices. However, female candidates and candidates not representing major parties were more likely to utilize a broader range of social media features and practices. The study adds support to the claim that campaigns do not simply adopt and utilize novel social media tools with the purpose of being innovative; they assess risks, costs and benefits. Social media do not alter the basic need of campaigns to control the message and to avoid stress in the campaign organization.  相似文献   
907.
Thomas König  Bernd Luig 《Public Choice》2014,160(3-4):501-519
According to the literature on parliamentary government, legislatures provide political parties with veto and amendment rights, which counterbalance executive power. This institutional feature is also said to help overcome ministerial “drift” within coalition governments. While this literature has focused on the situation of an unconstrained environment of parliamentary government, the European Union’s Member States continuously delegate policy competencies to Brussels, whose directives must in turn be transposed into national law to take effect. Because the minister in charge enjoys informational advantages and has the sole right to begin the process of implementing directives, he can completely control the agenda in this constrained environment. We evaluate the empirical implications of a ministerial gatekeeping model by investigating the (in)activities of 15 countries with respect to 2,756 EU directives adopted between December 1978 and November 2009. Our findings show that partisan ministerial approval is necessary to start the implementation process which conditions the counterbalancing response of parliaments. Accordingly, the delegation of policy competencies to the European Union changes the power relationship in parliamentary governments and increases the risk of partisan ministerial drift.  相似文献   
908.
The jurisdiction of the Hannover Institute of Legal Medicine recently experienced an unusually high incidence of lethal child neglect, with three cases in a 5-month period in 1999. Case 1: A girl received an inappropriate and inadequate diet of tea and oatmeal. The child was never breastfed, nor did it ever receive any other formula. The parents report the infant to have been healthy until she suddenly began projectile vomiting at the age of 13 weeks. For the next 3 days the infant was not able to maintain an adequate intake. The mother reports finding the child dead in its bed on the morning of the fourth day. Attempts by medical personnel to revive the child were unsuccessful. Case 2: A mother began spoon-feeding the infant puree on the fourth day of life, which according to the manufacturer's specifications is suitable for children between 4 and 8 months of age. At the age of 5 weeks, the infant was reported to have vomited half the just previously ingested meal, after which she took a nap. Some time later the parents observed the infant to be quite pale, however, assumed this was a result of sleep. When the mother finally did pick her up, the child was lifeless, and the parents brought her to the hospital. Medical personnel could however, only declare the infant dead, documenting a rectal temperature of 30 degrees C. Case 3: A 3.5-year-old girl died after her mother left the locked apartment and did not return for several weeks. The body of the child was found lying dressed on the floor in a state of advanced decay and mummification. Common findings in all three cases include lack of prenatal care, home birth without the help of a midwife, low socioeconomic status or maternal alcohol abuse, body weights below the 3rd percentile, extreme dehydration, fatty hepatic degeneration, thymic atrophy and signs of aspiration.  相似文献   
909.
Demodex is an ectoparasite living in the skin as a nonpathogen or a pathogen. It is also known that demodex acts as a vector of pathogenic microorganisms. In this study, we have investigated the rate of occurrence and vitality of demodex in forensic autopsies that have a high risk of contamination by infected organisms. The study, which was cross-sectional, conducted on 100 autopsy cases: 77 of the bodies were male and 23 female. The average age was 41. The samples were taken from the forehead, nose, cheeks, eyelashes and the temporal areas using the standardized skin surface biopsy and hair epilation techniques that were modified for this study. The data obtained were assessed statistically. Demodex was determined in 10% of all the cases. The cases revealed that demodex increased in old age and was more frequently seen in people with fair complexion. It was most frequently found in the forehead and the cheek. The longest postmortem interval in the positive cases was 55 h. The relationship between the postmortem interval and the presence of demodex was not statistically significant. Considering the fact that demodex, which is transmitted from human to human through skin contact, acts as a vector of pathogenic organisms and can stay alive in dead bodies for a long time, we think that the personnel performing autopsies without taking the necessary precautions are under risk.  相似文献   
910.
Gunshot wounds to the brain usually lead to acute respiratory arrest or death after a brief survival period, even in cases involving only slight direct tissue damage. It can be assumed therefore that the damage extends beyond the zone of recognizable destruction and hemorrhages. To determine the true extent of the tissue injury resulting from gunshot wounds to the brain, we carried out microscopic investigations for reactive changes (emigration of leukocytes and macrophages, axonal expression of beta-amyloid precursor protein (beta-APP) in 10 cases of gunshot wound to the narrow channel of the brain with survival times >2h. Demonstration of leukocytes expressing naphthol AS-D chloroacetate esterase activity in the brain tissue at the border of the missile track established the vitality of the gunshot effect. The presence of macrophages (CD68-epitope) allowed demarcation of a 1-2mm wide necrotic zone around the permanent cavity. Within this zone and beyond, beta-APP showed an initial increase followed by a decline in the number of injured axons. Three types of beta-APP positive staining could be differentiated. In the immediate vicinity of the missile track beta-APP positive neurons were present at a distance of 2-4mm from the margin of the permanent cavity (type 1) as a result of primary injured neuronal tissue by the gunshot itself. At longer distances from the narrow channel and the permanent cavity single beta-APP positive axons or axon fragments and two additional types were found; type 2 shows a parallel, wave-like arrangement of the damaged fibers, which suggests that the injury was produced by mechanical acceleration of the brain tissue created by the energy the projectile expended within the brain; irregular aggregation of beta-APP positive axons or axon fragments within a local edema represents type 3, which may be attributed to secondary ischemia or edema.  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