全文获取类型
收费全文 | 24397篇 |
免费 | 751篇 |
专业分类
各国政治 | 1227篇 |
工人农民 | 955篇 |
世界政治 | 2034篇 |
外交国际关系 | 907篇 |
法律 | 14286篇 |
中国共产党 | 3篇 |
中国政治 | 213篇 |
政治理论 | 5270篇 |
综合类 | 253篇 |
出版年
2020年 | 307篇 |
2019年 | 364篇 |
2018年 | 496篇 |
2017年 | 567篇 |
2016年 | 605篇 |
2015年 | 446篇 |
2014年 | 500篇 |
2013年 | 2601篇 |
2012年 | 586篇 |
2011年 | 695篇 |
2010年 | 535篇 |
2009年 | 582篇 |
2008年 | 636篇 |
2007年 | 640篇 |
2006年 | 614篇 |
2005年 | 555篇 |
2004年 | 584篇 |
2003年 | 618篇 |
2002年 | 515篇 |
2001年 | 942篇 |
2000年 | 874篇 |
1999年 | 731篇 |
1998年 | 403篇 |
1997年 | 331篇 |
1996年 | 298篇 |
1995年 | 289篇 |
1994年 | 335篇 |
1993年 | 303篇 |
1992年 | 451篇 |
1991年 | 486篇 |
1990年 | 443篇 |
1989年 | 439篇 |
1988年 | 431篇 |
1987年 | 455篇 |
1986年 | 462篇 |
1985年 | 449篇 |
1984年 | 406篇 |
1983年 | 439篇 |
1982年 | 330篇 |
1981年 | 297篇 |
1980年 | 246篇 |
1979年 | 325篇 |
1978年 | 228篇 |
1977年 | 197篇 |
1976年 | 184篇 |
1975年 | 168篇 |
1974年 | 178篇 |
1973年 | 159篇 |
1972年 | 154篇 |
1971年 | 138篇 |
排序方式: 共有10000条查询结果,搜索用时 2 毫秒
921.
Latinx youth living in the United States reside in a myriad of cultural and neighborhood contexts, yet little is known regarding how cultural values influence behavior problems across neighborhood contexts. Using a person–environment fit framework, the present study explored the degree to which youth cultural values were associated with their externalizing problems, and the degree to which this association was shaped by their neighborhood’s socioeconomic status (SES), and Latinx and immigrant concentration. The sample comprised of 998 Latinx youth (Female?=?54.2%), ages 10 to 14 years old (Mage?=?11.8), from three large United States metropolitan areas. Multilevel modeling methods indicated that increased fit between youth cultural values and neighborhood Latinx and immigrant concentration was associated with fewer externalizing problems, but only in higher SES neighborhoods. The results support the importance of studying social determinants of Latinx youth behavioral health, and provide implications for both neighborhood-level and individual-level prevention and intervention programming. 相似文献
922.
Katharine N. Rankin Andrea J. Nightingale Pushpa Hamal Tulasi S. Sigdel 《The Journal of peasant studies》2018,45(2):280-299
This paper explores the political field that has opened up in the wake of the recent civil war in Nepal. We focus on cultural-political developments in agrarian districts, where some of the most intriguing openings, and indeed the most pernicious closures, can be witnessed (as opposed to the national-state restructuring that commands more media and popular attention). Our research asks what spaces open up in the emerging political field at the district scale to entrench or transform dominant cultural codes and sedimented histories of socio-economic inequality. Preliminary research identifies specific sectors of local governance that have emerged as significant sites of struggle over the shape and meaning of ‘democracy’, namely forest management and infrastructure development. The primary contribution of the paper lies in specifying an analytical approach to the study of ‘post-conflict’ governance at the local scale via three conceptual terrains of inquiry – governance and planning, political subjectivity, and cultural politics. The ultimate objective is to develop a framework for assessing the conditions of possibility for a democratic restructuring of economy and society to accompany the official political institutions of liberal democracy. 相似文献
923.
This report describes a collaborative study on typing group-specific component (GC), conducted between the Central Research and Support Establishment and the forensic science laboratories of England, Wales and Northern Ireland. A population study (n=114) was performed. Fifty blood donors were selected to provide a distribution, slightly biased from normal, in favour of the GC 1F-1F and GC 1F-1S phenotypes. A protocol was devised for preparing large bloodstains. The strongest GC bands were obtained from the edge of a stain after the blood had been treated with K+/EDTA. Each laboratory received a representative portion of the large bloodstains for GC typing. Five of the eight laboratories correctly grouped all the bloodstains. No errors directly attitributable to the system were recorded in over 800 tests, indicating that GC in bloodstains can be typed reliably using the combination of isoelectric focusing in ultrathin narrow pH interval gels followed by immunofixation and silver staining. 相似文献
924.
A continuous model for interpreting the positions of bands in DNA locus-specific work. 总被引:1,自引:0,他引:1
A simple but rigorous approach is offered for evaluating the evidential value of single locus DNA autoradiographs. This approach does not use a binning technique and it does not treat alleles as discrete variables. Instead, the allele distribution is considered to be continuous. The variation between two comparable bands is assessed using previously determined experimental parameters. The Bayesian treatment leads to an expression of the "quality of a match". 相似文献
925.
A method for the routine profiling of illicit heroin samples received in casework has been developed which depends on simple and straightforward sample pretreatment, followed by gas chromatography on a capillary column using flame-ionization detection. The factors affecting the choice of each aspect of the procedure are discussed, as are the statistical data for sampling and the chromatography. Components of illicit heroin derived from opium and other adulterants have been identified. The significance of data from samples examined in 1986 is discussed. 相似文献
926.
The eyes of fourteen fatally abused children and sixteen control cases were examined histopathologically. Ten of the abused children showed intraocular change. The most common ocular changes were subdural hemorrhage of the optic nerve and retinal hemorrhage which involved all the layers of the retina, but most commonly the nerve fiber layer, ganglion cell layer and inner nuclear layer. The presence of blood cavities within the retina partially supported the hypothesis of traumatic retinoschisis. The control cases of non-abused children rarely showed intraocular hemorrhage. 相似文献
927.
A 54 year-old female expired at her residence. Her husband, a physician, signed a certificate stating that her death was due to cerebrovascular accident (CVA) and released her body to a funeral home, where she was embalmed. Since the deceased had a long history of medical problems and drug abuse, an autopsy was performed and no evidence of CVA was found. Toxicological analyses of body fluids and tissues revealed the presence of ethchlorvynol in high concentration in the bile (112 mg/l). The bloody fluid collected from the heart contained a concentration of ethchlorvynol below the limit for quantitation. Other findings included phenobarbital (32.8 mg/l) in heart bloody fluid and methanol (an ingredient of embalming fluid). The significance of the findings is discussed in relation to embalmment prior to autopsy and toxicological analyses. Ethchlorvynol concentration in the bile is compared to other fatal cases due to ethchlorvynol overdose. 相似文献
928.
Signs of hypothermia injury were studied in rabbits cooled to a core temperature of 30 degrees C by immersion in ice water and thereafter rewarmed to 35 degrees C. Anaesthetized control rabbits were kept normothermic (37 degrees C) for a corresponding time (4 h). Creatine phosphokinase (CPK) activity increased 24 h after hypothermia to 20-fold in serum. In cerebrospinal fluid the activity was already significantly (5-fold) increased after hypothermia and was still as high at 24 h. Smaller increase was also found in the control normothermic rabbits both in serum (10-fold) and cerebrospinal fluid (2-fold). The values had returned to the initial level after 1 week. Small haemorrhages were observed in the brain at 24 h and slight scarring was seen in the myocardium of some rabbits which had lived 4 weeks following hypothermia. The results indicate that CPK can be a useful marker in the diagnostics of hypothermia death, especially in cerebrospinal fluid, which is less affected than blood by autolysis. 相似文献
929.
J Schlumbohm 《The History of the Family》1996,1(1):81-95
"Current models of the European demo-economic system in pre-industrial times are based on strong assumptions about the predominant patterns of individual life courses. Now recent micro-studies of individual communities make it possible to check whether the actual patterns of life fit these assumptions. The findings for Belm present an amazing blend of confirmations and contradictions. In particular, the connection between marriage and the formation of a new self-supporting household is subject to doubt. Together with the findings of other micro-studies, the evidence for Belm suggests that the assumptions about mechanisms linking marriage to economic resources should be reconsidered, and that there is need for a dialogue between macro-theories and micro-history." 相似文献
930.
This paper describes a simplified approach to calculating the Bayesian likelihood ratio for the case where two DNA single locus profiles are to be compared. It explains how the calculation allows for band shift and also for the variation in precision with molecular weight. A simple basic theory section explains the principles of the analysis but more detailed explanations are given in an advanced theory section. Experiments on substantial data collections are described which demonstrate the robustness of the method. 相似文献