全文获取类型
收费全文 | 16806篇 |
免费 | 279篇 |
专业分类
各国政治 | 647篇 |
工人农民 | 1436篇 |
世界政治 | 676篇 |
外交国际关系 | 536篇 |
法律 | 10109篇 |
中国共产党 | 3篇 |
中国政治 | 57篇 |
政治理论 | 3545篇 |
综合类 | 76篇 |
出版年
2020年 | 109篇 |
2019年 | 145篇 |
2018年 | 1435篇 |
2017年 | 1369篇 |
2016年 | 1190篇 |
2015年 | 207篇 |
2014年 | 171篇 |
2013年 | 997篇 |
2012年 | 412篇 |
2011年 | 1116篇 |
2010年 | 1160篇 |
2009年 | 765篇 |
2008年 | 966篇 |
2007年 | 897篇 |
2006年 | 265篇 |
2005年 | 285篇 |
2004年 | 399篇 |
2003年 | 343篇 |
2002年 | 240篇 |
2001年 | 270篇 |
2000年 | 275篇 |
1999年 | 198篇 |
1998年 | 127篇 |
1997年 | 133篇 |
1996年 | 131篇 |
1995年 | 128篇 |
1994年 | 116篇 |
1993年 | 116篇 |
1992年 | 186篇 |
1991年 | 200篇 |
1990年 | 180篇 |
1989年 | 182篇 |
1988年 | 162篇 |
1987年 | 181篇 |
1986年 | 176篇 |
1985年 | 164篇 |
1984年 | 166篇 |
1983年 | 173篇 |
1982年 | 100篇 |
1981年 | 91篇 |
1980年 | 77篇 |
1979年 | 111篇 |
1978年 | 84篇 |
1977年 | 82篇 |
1976年 | 60篇 |
1975年 | 59篇 |
1974年 | 63篇 |
1973年 | 73篇 |
1972年 | 63篇 |
1968年 | 53篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
951.
Andrea M. Rogow James E. Marcia Ben R. Slugoski 《Journal of youth and adolescence》1983,12(5):387-400
Eighty college males were given an expanded identity status interview which included two new interpersonal-sexual areas, “attitudes towards sexual expression” and “sex-role beliefs.” The relative contribution of the new content areas as well as of the standard three areas (occupation, religion, and politics) to overall identity status was assessed by noting the extent of correspondence. Identity status in each content area was also compared with performance on the dependent variable of cognitive complexity. Ideology contributed more than occupation both to overall status rating, as well as to discrimination on the dependent variable. Results on the two new areas supported the view that interpersonal-sexual concerns are important for men's identity development as well as for women's. The finding that all interview areas corresponded well with overall identity status and discriminated significantly on the dependent measure leads to the suggestion that the process variables of crisis and commitment may so overshadow a particular content area that any content of personal relevance for the late adolescent might be used in investigating ego identity development. 相似文献
952.
953.
Hanlon Thomas E. Bateman Richard W. Simon Betsy D. O'Grady Kevin E. Carswell Steven B. 《Journal of youth and adolescence》2002,31(6):459-471
This paper presents the results of an evaluation of an early intervention, risk-reduction strategy versus a standard intervention approach in the treatment of inner-city youth at high risk of adopting a deviant lifestyle. It examines baseline and 1-year follow-up information provided by 408 youth admitted to 2 community-based Baltimore City Youth Bureaus offering counseling services for neighborhood youth referred for delinquent and other problematic behavior. In the study, one of these bureaus served as the experimental intervention clinic and the other as the control, or standard intervention, clinic. Outcome measures involved substance abuse; sexual activity; contact with juvenile authorities; and delinquent activity, including violence-related activity. Regression analyses of outcome measures revealed significant differential results for delinquent activity, which favored the experimental intervention. Relationships between risk/protective factors and outcome are discussed. 相似文献
954.
955.
The conflicting outcome of the electoral and popular votes inthe 2000 presidential election provoked calls to abolish oralter the electoral college. One prominent criticism is thatthe institution distorts election outcomes by providing disproportionateinfluence to small states. If each state receives a number ofpresidential electors equal to that states' number of membersin the U.S. House of Representatives plus the two senators,then the "federalism bonus" represents the two electoral collegevotes that correspond to the position of each state as an equalentity in the Senate. This research examines how the "federalismbonus" influences presidential selection by addressing threequestions. First, why did the framers include a federal componentin the electoral college? Second, under what circumstances hasthe "federalism bonus" played a role in presidential selection?Third, how would the various alternatives for reform affectthe federal component of the electoral college, and what isthe likelihood of adoption for each? 相似文献
956.
957.
Validation of a 16-locus fluorescent multiplex system 总被引:24,自引:0,他引:24
Krenke BE Tereba A Anderson SJ Buel E Culhane S Finis CJ Tomsey CS Zachetti JM Masibay A Rabbach DR Amiott EA Sprecher CJ 《Journal of forensic sciences》2002,47(4):773-785
STR multiplexes have been indispensable for the efficient genotyping of forensic samples. The PowerPlex 16 System contains the coreCODIS loci, D3S1358, D5S818, D7S820, D8S1179, D13S317, D16S539, D18S51, D21S11, CSF1PO, FGA, THOI, TPOX, vWA, the sex determinant locus, amelogenin, and two pentanucleotide STR loci, Penta D and Penta E. This multiplex satisfies the locus requirements for most national databases and is the most efficient currently available system due to its single PCR amplification. To provide the groundwork for judicial acceptance, including the publication of primer sequences, and to evaluate laboratory-to-laboratory variation, a developmental validation for casework on this commercially available system was performed in 24 laboratories and produced the following conclusions. Amplification was reliable on a variety of thermal cyclers and product could be analyzed on either an ABI PRISM 310 Genetic Analyzer or an ABI PRISM 377 DNA Sequencer. Genotyping using single source samples was consistent between 0.25 and 2 ng of input DNA template with a few laboratories obtaining complete genotypes at 0.0625 ng. However, heterozygote allele imbalance (<60% peak height balance) caused by stochastic effects was observed at a rate of 13% with 0.125 ng DNA and 22% at 0.0625 ng DNA. Mixture analyses were done using a total of 1 ng of DNA template. Most alleles were detected in mixtures of 4 to 1 and some minor alleles were detected in mixtures of 19 to 1. Optimum amplification cycle number was dependent on the sensitivity of the detection instrument used and could also be adjusted to accommodate larger amounts of DNA on solid supports such as FTA paper. Reaction conditions including volume, annealing temperature, and concentrations of primer, AmpliTaq Gold, and magnesium were shown to be optimal yet robust enough to withstand moderate variations without affecting genotype analysis. Environmental, matrix and standard source analyses revealed an ability to obtain complete genotypes in all sample types except those exposed to 80 degrees C for 12-48 days. Finally, comparison of genotype results from the PowerPlex 16 System with other commercially available systems on non-probative reference and forensic samples showed consistent results. 相似文献
958.
959.
960.
Current procedures for human DNA quantitation reach their limit at 150 pg DNA, which is above the limit of the PCR profiling range using Profiler-Plus (Applied Biosystems, CA). This study tested the potential for the use of primate specific Alu sequences in forensic science for the sensitive detection and quantitaion of DNA. A fluorescently labelled primer pair was designed enabling high efficiency amplification of the core Alu sequence within primate DNA. Quantitation was performed by measurement of fluorescence intensity and comparison to a series of standard template DNA amounts via the construction of a standard curve. The new Alu-based quantitation protocol developed has shown its feasibility in more sensitively quantitating (100-2.5 pg) unknown amounts of human DNA for forensic use. The method is compatible with the use and throughput of current forensic procedures. 相似文献