全文获取类型
收费全文 | 26597篇 |
免费 | 1544篇 |
国内免费 | 5篇 |
专业分类
各国政治 | 1069篇 |
工人农民 | 1068篇 |
世界政治 | 1911篇 |
外交国际关系 | 826篇 |
法律 | 18064篇 |
中国共产党 | 7篇 |
中国政治 | 226篇 |
政治理论 | 4739篇 |
综合类 | 236篇 |
出版年
2020年 | 504篇 |
2019年 | 561篇 |
2018年 | 672篇 |
2017年 | 795篇 |
2016年 | 801篇 |
2015年 | 659篇 |
2014年 | 685篇 |
2013年 | 2584篇 |
2012年 | 693篇 |
2011年 | 783篇 |
2010年 | 852篇 |
2009年 | 829篇 |
2008年 | 747篇 |
2007年 | 759篇 |
2006年 | 808篇 |
2005年 | 676篇 |
2004年 | 665篇 |
2003年 | 681篇 |
2002年 | 605篇 |
2001年 | 1010篇 |
2000年 | 813篇 |
1999年 | 711篇 |
1998年 | 369篇 |
1997年 | 285篇 |
1996年 | 289篇 |
1995年 | 286篇 |
1994年 | 323篇 |
1993年 | 301篇 |
1992年 | 507篇 |
1991年 | 549篇 |
1990年 | 515篇 |
1989年 | 478篇 |
1988年 | 492篇 |
1987年 | 427篇 |
1986年 | 490篇 |
1985年 | 466篇 |
1984年 | 416篇 |
1983年 | 383篇 |
1982年 | 308篇 |
1981年 | 304篇 |
1980年 | 241篇 |
1979年 | 306篇 |
1978年 | 211篇 |
1977年 | 177篇 |
1976年 | 156篇 |
1975年 | 189篇 |
1974年 | 192篇 |
1973年 | 163篇 |
1972年 | 150篇 |
1971年 | 150篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
981.
Selena McKay-Davis M.F.S. Tharinia Robinson Ph.D. Ismail M. Sebetan M.D. Ph.D. Paul Stein Ph.D. 《Journal of forensic sciences》2020,65(6):2065-2070
Forensic Technicians provide crime scene investigation services and are exposed to stressful violent crimes, motor vehicle accidents, biological or chemical hazards, and other appalling imagery. Forensic Technicians would likely experience physical and psychological stress after exposure to trauma, and security vulnerabilities similar to Sworn Police Officers. The perceived availability of mental health resources, job-related physical, psychological stress, and traumatic experiences of both Forensic Technicians and Sworn Police Officers from California law enforcement agencies were investigated using a self-reported survey. Responses were evaluated for any significant differences in the perceived stress, job-related physical stress, and resulting psychological impact affecting the participants. The survey contained a mix of True/False, Circle/Check the Appropriate Box, or Likert Scale (1–5) responses. The results were evaluated statistically and discussed. Results indicated Sworn Police Officers and Forensic Technicians have different on-duty stress levels, but similar off-duty stress levels. Nearly two-thirds of 54 job-related stressors were not significantly different between the two occupations. However, Forensic Technicians reported more adverse effects in 17 physical and psychological job-related activities compared with Sworn Police Officers. Forensic Technicians reported lower awareness levels and availability of agency mental health support services than were reported by Sworn Police Officers. This study reports for the first time an unexpected outcome that perceived and job-related psychological stress is greater for Forensic Technicians than Sworn Police Officers. Possible reasons for this disparity will be discussed as well as stress management tools that should be implemented to reduce health risk factors for both career professionals as well as increase public safety. 相似文献
982.
Minji Lee M.S. Ju Yeon Jung M.S. Sungsoo Choi M.S. Ilung Seol Ph.D. Seohyun Moon Ph.D. In Kwan Hwang Ph.D. 《Journal of forensic sciences》2020,65(6):2117-2120
Lophophora is a member of the Cactaceae family, which contains two species: Lophophora williamsii and L. diffusa. Lophophora williamsii is an illegal plant containing mescaline, a hallucinogenic alkaloid. In this study, a novel method based on a single nucleotide polymorphism (SNP) assay was developed for identifying L. williamsii; this assay reliably detects SNPs within chloroplast DNA (rbcL, matK, and trnL-trnF IGS) and was validated for identifying Lophophora and L. williamsii simultaneously. The chloroplast DNA sequences from four L. williamsii and three L. diffusa plants were obtained and compared using DNA sequence data from approximately 300 other Cactaceae species available in GenBank. From this sequence data, a total of seven SNPs were determined to be suitable for identifying L. williamsii. A multiplex assay was constructed using the ABI PRISM® SNaPshot™ Multiplex Kit (Applied Biosystems, Forster City, CA) to analyze species-specific SNPs. Using this multiplex assay, we clearly distinguished the Lophophora among 19 species in the Cactaceae family. Additionally, L. williamsii was distinguished from L. diffusa. These results suggest that the newly developed assay may help resolve crimes related to illegal distribution and use. This multiplex assay will be useful for the genetic identification of L. williamsii and can complement conventional methods of detecting mescaline. 相似文献
983.
Research indicates that voters are not particularly effective at removing corrupt politicians from office, in part because voters make decisions on the basis of many competing factors. Party leaders are much more single-minded than voters and will choose to deselect implicated legislators if it means maintaining a positive party reputation and improving the odds of winning a legislative majority. We examine renominations to Italy’s legislature in two periods marked by corruption. We compare these renomination patterns with those from the prior legislature, when corruption lacked political salience. Our analysis shows that incumbent renominations are negatively associated with the number of press mentions that link the incumbent to corruption—but only when corruption is salient to the public. Our study highlights the importance of party leaders in forcing malfeasant legislators out of office—and reducing corruption—and redirects attention from voters to political elites as a critical channel in enforcing democratic accountability. 相似文献
984.
A Pretext for Regression? The Gendered Institutional Response to COVID-19 in the Country of Football
This article considers the gendered institutional response to COVID-19 in Brazilian football. It is argued that the asymmetries of power which shaped policy are rooted in the historical marginalisation of women's sports in the country along with socially constructed notions of hegemonic masculinity. The COVID-19 pandemic has served to accentuate deeply embedded social and economic inequalities and may serve as a pretext for eroding precarious gains made in recent times. 相似文献
985.
Patrick Megan E. Rhew Isaac C. Duckworth Jennifer C. Lewis Melissa A. Abdallah Devon Alisa Lee Christine M. 《Journal of youth and adolescence》2020,49(4):869-880
Journal of Youth and Adolescence - Young adults experience social role transitions across multiple life domains, and a deeper understanding of the ways in which these simultaneous transition... 相似文献
986.
Dykstra Victoria W. Willoughby Teena Evans Angela D. 《Journal of youth and adolescence》2020,49(1):49-59
Journal of Youth and Adolescence - Previous studies suggest parents lack knowledge regarding child and adolescent lie-telling; however, no study to date has examined children’s and... 相似文献
987.
Youngmin Kim M.S. Won-sil Choi Ph.D. Byoungjun Jeon B.S. Tae Hyun Choi M.D. Ph.D. 《Journal of forensic sciences》2020,65(2):458-464
Cholesterol and squalene are fatty materials of latent fingermarks that can be utilized for dating methodologies and visualization techniques. Previous studies have suggested these compounds undergo degradation in fingermarks as a function of time (days) and light at ambient temperature. However, studies assessing how their composition changes at low and high temperatures over short periods of time (hours) have not been published previously. Here, we performed quantitative analysis of cholesterol and squalene in natural fingermark residue using PVDF membrane, after exposure to a range of temperatures (−20 to 100°C) for 4 and 8 h. We found that levels of both fatty materials remained constant at −20 to 60°C, but both showed significant reduction at 100°C, over short exposure times. These results indicate that cholesterol and squalene are detectable at −20 to 60°C, whereas at 100°C or higher, both are lost due to rapid thermal degradation. 相似文献
988.
Sierra F. Kaszubinski B.Sc. Jennifer L. Pechal Ph.D. Carl J. Schmidt M.D. Heather R. Jordan Ph.D. Mark E. Benbow Ph.D. Mariah H. Meek Ph.D. 《Journal of forensic sciences》2020,65(2):513-525
Microbial communities have potential evidential utility for forensic applications. However, bioinformatic analysis of high-throughput sequencing data varies widely among laboratories. These differences can potentially affect microbial community composition and downstream analyses. To illustrate the importance of standardizing methodology, we compared analyses of postmortem microbiome samples using several bioinformatic pipelines, varying minimum library size or minimum number of sequences per sample, and sample size. Using the same input sequence data, we found that three open-source bioinformatic pipelines, MG-RAST, mothur, and QIIME2, had significant differences in relative abundance, alpha-diversity, and beta-diversity, despite the same input data. Increasing minimum library size and sample size increased the number of low-abundant and infrequent taxa detected. Our results show that bioinformatic pipeline and parameter choice affect results in important ways. Given the growing potential application of forensic microbiology to the criminal justice system, continued research on standardizing computational methodology will be important for downstream applications. 相似文献
989.
Sabrina Zorbo M.S. Patrick P. J. M. H. Jeuniaux Ph.D. 《Journal of forensic sciences》2020,65(2):641-648
In the case of suspicious deaths, the technique of 1:1 taping is often used in Belgium. It consists of affixing a large number of adhesive tapes to the body of the victim. It is conventionally aimed at obtaining microtraces (e.g., fibers, hair) and is usually not used for DNA analysis. However, in some cases, DNA analysis of certain areas of interest identified on the 1:1 taping material can offer a last resort solution. The four-step method that is described in this article involves the selection of areas of interest on the body (Step 1), the selection of the corresponding tapes (Step 2), the decontamination of the tapes (Step 3), the selection of areas of interest on the tapes, for DNA sampling (Step 4). The method is illustrated by its successful application in four murder cases. In each case, DNA profiles of good quality could be identified, including profiles of persons different from the victim. 相似文献
990.
Wu-ting Tsai Ph.D. Chia-I Hu M.S. Chia-Yun Chang L.L.M. 《Journal of forensic sciences》2020,65(1):255-258
The horizontal displacement of the human body resulting from fatal fall from a height is an important variable commonly used to inversely determine the cause or identify other forensic aspects of the fall. When examining the horizontal displacement, the wind effect is generally ignored. This technical note reports analytical modeling of the falling process, utilizing previous measurements of wind force acting on the human body, for determining the functional relationship between the wind speed and the horizontal displacement in the falling process. The result reveals that it does not take extremely rare wind conditions to cause a considerable shift of the human body, highlighting the importance to consider wind as a factor in investigations of fatal falls. 相似文献