全文获取类型
收费全文 | 1697篇 |
免费 | 18篇 |
专业分类
各国政治 | 49篇 |
工人农民 | 160篇 |
世界政治 | 39篇 |
外交国际关系 | 37篇 |
法律 | 1262篇 |
中国政治 | 9篇 |
政治理论 | 155篇 |
综合类 | 4篇 |
出版年
2023年 | 6篇 |
2022年 | 4篇 |
2021年 | 11篇 |
2020年 | 13篇 |
2019年 | 16篇 |
2018年 | 93篇 |
2017年 | 30篇 |
2016年 | 101篇 |
2015年 | 25篇 |
2014年 | 18篇 |
2013年 | 47篇 |
2012年 | 129篇 |
2011年 | 91篇 |
2010年 | 15篇 |
2009年 | 29篇 |
2008年 | 15篇 |
2007年 | 24篇 |
2006年 | 25篇 |
2005年 | 406篇 |
2004年 | 109篇 |
2003年 | 29篇 |
2002年 | 21篇 |
2001年 | 18篇 |
1999年 | 14篇 |
1996年 | 4篇 |
1992年 | 22篇 |
1991年 | 23篇 |
1990年 | 29篇 |
1989年 | 39篇 |
1988年 | 28篇 |
1987年 | 27篇 |
1986年 | 30篇 |
1985年 | 20篇 |
1984年 | 14篇 |
1983年 | 15篇 |
1980年 | 3篇 |
1979年 | 10篇 |
1978年 | 10篇 |
1977年 | 5篇 |
1975年 | 14篇 |
1974年 | 24篇 |
1973年 | 14篇 |
1972年 | 16篇 |
1971年 | 19篇 |
1970年 | 13篇 |
1969年 | 7篇 |
1968年 | 11篇 |
1967年 | 9篇 |
1966年 | 5篇 |
1965年 | 5篇 |
排序方式: 共有1715条查询结果,搜索用时 15 毫秒
61.
Soares-Vieira JA Billerbeck AE Pinto EM Iwamura ES Bilharinho de Mendonça B Otto PA 《The American journal of forensic medicine and pathology》2002,23(2):186-190
Gene and genotype frequencies in relation to the D3S1358, vWA, FGA, TH01, TPOX, CSF1PO, D5S818, D13S317, and D7S820 loci were determined in a sample of 290 unrelated individuals (204 Caucasians and 86 mulattoes) living in the city of S?o Paulo, Brazil. The sex test Amelogenin was also performed in all subjects from our sample, revealing the expected sex in all instances. Allele frequency data obtained from the analysis of these samples were in the usual range of other population groups with similar racial background. In the sample of Caucasian individuals, panmictic proportions were ruled out in relation to TPOX and CSF1PO loci, but only in the latter was the overall frequency of heterozygotes significantly less than expected. In the sample of mulattoes, Hardy-Weinberg proportions were rejected in relation to FGA and CSF1PO loci, but in no instance were the overall numbers of heterozygotes different from the corresponding expected ones under panmixia. Taking into account all this and also the number of tests performed, the degree of genetic heterogeneity of Brazilian populations, and the critical level reached by the significant results (1% < alpha<5%), the departures from panmixia here observed can be considered to be negligible in altering significantly biologic relationship odds calculated under the assumption of random matings. 相似文献
62.
Baptista MJ Monsanto PV Pinho Marques EG Bermejo A Avila S Castanheira AM Margalho C Barroso M Vieira DN 《Forensic science international》2002,128(1-2):66-78
A sensitive analytical method was developed for quantitative analysis of delta(9)-tetrahydrocannabinol (delta(9)-THC), 11-nor-delta(9)-tetrahydrocannabinol-carboxylic acid (delta(9)-THC-COOH), cannabinol (CBN) and cannabidiol (CBD) in human hair. The identification of delta(9)-THC-COOH in hair would document Cannabis use more effectively than the detection of parent drug (delta(9)-THC) which might have come from environmental exposure. Ketamine was added to hair samples as internal standard for CBN and CBD. Ketoprofen was added to hair samples as internal standard for the other compounds. Samples were hydrolyzed with beta-glucuronidase/arylsulfatase for 2h at 40 degrees C. After cooling, samples were extracted with a liquid-liquid extraction procedure (with chloroform/isopropyl alcohol, after alkalinization, and n-hexane/ethyl acetate, after acidification), which was developed in our laboratory. The extracts were analysed before and after derivatization with pentafluoropropionic anhydride (PFPA) and pentafluoropropanol (PFPOH) using a Hewlett Packard gas chromatographer/mass spectrometer detector, in electron impact mode (GC/MS-EI). Derivatized delta(9)-THC-COOH was also analysed using a Hewlett Packard gas chromatographer/mass spectrometer detector, in negative ion chemical ionization mode (GC/MS-NCI) using methane as the reagent gas. Responses were linear ranging from 0.10 to 5.00 ng/mg hair for delta(9)-THC and CBN, 0.10-10.00 ng/mg hair for CBD, 0.01-5.00 ng/mg for delta(9)-THC-COOH (r(2)>0.99). The intra-assay precisions ranged from <0.01 to 12.40%. Extraction recoveries ranged from 80.9 to 104.0% for delta(9)-THC, 85.9-100.0% for delta(9)-THC-COOH, 76.7-95.8% for CBN and 71.0-94.0% for CBD. The analytical method was applied to 87 human hair samples, obtained from individuals who testified in court of having committed drug related crimes. Quantification of delta(9)-THC-COOH using GC/MS-NCI was found to be more convenient than GC/MS-EI. The latter may give rise to false negatives due to the detection limit. 相似文献
63.
Lothar D?hn 《Politische Vierteljahresschrift》2002,43(1):195
64.
65.
66.
To answer the question whether a negative result of gas chromatographic blood analysis for components of chemical mace proves that no or at most only slight tear gas exposure can have occurred, animal experiments were carried out. In the blood of 10 guinea pigs, which were exposed to the contents of chemical mace for 1--6 h, the solvants 1,1,2-trichloro-1,2,2-trifluorethane (freon 113) and 1,1,1-trichloroethane could easily be detected--even 23 h after the end of exposure or after a storage of the blood samples for 18 weeks--whereas the lacrimator chloracetophenone (CN) could not be found at all. In vitro experiments showed that CN relatively quickly reacts with components of blood. Therefore, blood samples should be analyzed for CN after withdrawal as soon as possible. In case of inhalation of the contents of chemical mace, i.e., after the comparatively mildest form of CN application, most probably no traces of the lacrimator at all can pass into the blood due to the quick reaction of CN with proteins of the respiratory surface of the lung. 相似文献
67.
Reviews the need for and development of expanded school mental health (ESMH) programs, which provide a continuum of mental health promotion and intervention through school–community partnerships. Since ESMH is a relatively new, but increasingly prominent field, countless issues are being addressed in practice and research and in efforts to bridge practice and research. We review particular content and context dimensions of ESMH in need of development including quality assessment and improvement, empirically supported practice, improving assessment and outcome evaluation, involving educators in the work, understanding school environments, and tailoring programs through qualitative research. Summaries of articles that amplify these themes are provided. 相似文献
68.
In this paper symbolic inclusion/exclusion processes in sport with respect to gender and ethnicity among adolescents (n = 1025) are analyzed from a social-critical perspective. It was found that sport participation preferences of young people are still influenced by dominant normative gendered and racial/ethnic images. Sport can serve not only as an agent of integration among youth, but is also used to differentiate and discriminate. On one hand sport participation is less predictable with respect to gender, due for example to interactions with ethnicity. Although ethnic minority girls participate the least in sport, ‘black,’ traditional ‘masculine‘ sports such as soccer and fighting/self-defense are valued relative highly. On the other hand, the data show that especially the male adolescents symbolically exclude girls from ‘masculine’ sports such as soccer; in addition for both ethnic minority and majority boys the fear of being labelled as a ‘sissy’ works as a strong mechanism of self-exclusion from participation in traditional ‘feminine’ sports. However, stereotypical normative images are not only confirmed through sport (participation), but also continually challenged.Researcher/lecturer, Tilburg University. Research interest in inclusionary and exclusionary mechanisms in sport, especially with respect to gender, ethnicity and sexuality.Senior researcher, Utrecht University. Major research interest in gender, ethnicity and leadership positions in sport. 相似文献
69.
The authors investigated the dimensions and mechanisms of belonging relevant to motivation and achievement among high school students representing 4 ethnic groups. Using survey data from 9th to 12th grade students (N = 5,494) attending 7 ethnically-diverse high schools, structural equation modeling was employed to explore, independently for each ethnic group, the relationships between students’ perceptions of their belonging (encompassing relationships with teachers and peers, extracurricular involvement, and perceived ethnic-based discrimination), motivation (efficacy beliefs and valuing school activities), and academic success. All 4 measures of belonging were significant for European-American and Latino students. However, friendship nominations were not significant for all groups, suggesting potential variability in perspectives across ethnic groups. The strength of the structural model postulating belonging as a mediator, including statistically significant indirect paths, supported the hypothesis that the belonging construct accounted for much of the relationship between student motivation and success across groups.Beverly Faircloth is a doctoral candidate of the University of North Carolina at Chapel Hill. Her research interests include the developmental and motivational processes that support adolescent school engagement in ethnically diverse settings.Jill Hamm is an Assistant Professor at the University of North Carolina at Chapel Hill. She received her Ph.D. from the University of Wisconsin-Madison in 1996. Her research interests are adolescents’ peer relations in ethnically diverse schools and classrooms. 相似文献
70.
Inge?VanderValkEmail author Ed?Spruijt Martijn?de?Goede Cora?Maas Wim?Meeus 《Journal of youth and adolescence》2005,34(6):533-546
In the present longitudinal 3-wave study of 1274 adolescents and young adults, aged 12–24 at the 1st wave, it is examined
whether youngsters from intact versus postdivorce families show long-term differences in internalizing and externalizing problems.
Furthermore, possible differences in the development of this problem behavior between offspring from intact and postdivorce
families are examined, i.e., possible differences in growth curves of internalizing and externalizing problems are investigated.
Longitudinal multilevel analyses reveal long-term differences in internalizing and externalizing problems according to family
structure. Adolescents and young adults growing up in postdivorce families display more internalizing and externalizing problem
behavior than youngsters of intact families. The development of these 2 types of problem behavior does not differ by gender
or family structure. That is, the shape of the growth curves of internalizing and externalizing problem behavior is similar
for boys and girls and also for youngsters from intact and postdivorce families.
Inge VanderValk is a Postdoc Researcher at the Department of Child and Adolescent Studies, Utrecht University, the Netherlands.
She received her Ph.D. in 2004 from Utrecht University. Her major research interests include associations between adolescent
adjustment and parental marital quality and parental divorce.
Ed Spruijt is an Associate Professor at the University of Utrecht. He received his Ph.D. in 1983 from Utrecht University.
His major research interests are the consequences of parental divorce and visitation arrangements on children.
Martijn de Goede is an associate Professor at Utrecht University, Department of Methodology and Statistics. He received his
Ph.D. in 1988 from Utrecht University. His major research interests are occupational and relational life courses of youngsters.
Cora Maas is an Assistent Professor at Utrecht University, Department of Methodology and Statistics. She received her PH.D.
in 1992 in Utrecht from Utrecht University. Her major interests are: multilevel analysis (theory and applications).
Wim Meeus is full Professor of Adolescent Development at Utrecht University. He received his Ph.D. in 1984 from Utrecht University.
His major research interests are personality, identity, and relationships in adolescence. 相似文献