全文获取类型
收费全文 | 11638篇 |
免费 | 917篇 |
国内免费 | 40篇 |
专业分类
耳鼻咽喉 | 117篇 |
儿科学 | 394篇 |
妇产科学 | 249篇 |
基础医学 | 1685篇 |
口腔科学 | 354篇 |
临床医学 | 1235篇 |
内科学 | 2159篇 |
皮肤病学 | 167篇 |
神经病学 | 966篇 |
特种医学 | 757篇 |
外国民族医学 | 2篇 |
外科学 | 1739篇 |
综合类 | 127篇 |
一般理论 | 11篇 |
预防医学 | 820篇 |
眼科学 | 291篇 |
药学 | 634篇 |
中国医学 | 12篇 |
肿瘤学 | 876篇 |
出版年
2023年 | 103篇 |
2022年 | 181篇 |
2021年 | 403篇 |
2020年 | 226篇 |
2019年 | 312篇 |
2018年 | 378篇 |
2017年 | 246篇 |
2016年 | 240篇 |
2015年 | 269篇 |
2014年 | 367篇 |
2013年 | 502篇 |
2012年 | 632篇 |
2011年 | 568篇 |
2010年 | 404篇 |
2009年 | 306篇 |
2008年 | 499篇 |
2007年 | 512篇 |
2006年 | 485篇 |
2005年 | 431篇 |
2004年 | 381篇 |
2003年 | 341篇 |
2002年 | 327篇 |
2001年 | 233篇 |
2000年 | 216篇 |
1999年 | 215篇 |
1998年 | 206篇 |
1997年 | 178篇 |
1996年 | 197篇 |
1995年 | 144篇 |
1994年 | 129篇 |
1993年 | 133篇 |
1992年 | 147篇 |
1991年 | 169篇 |
1990年 | 160篇 |
1989年 | 201篇 |
1988年 | 162篇 |
1987年 | 170篇 |
1986年 | 156篇 |
1985年 | 145篇 |
1984年 | 97篇 |
1983年 | 104篇 |
1982年 | 92篇 |
1980年 | 87篇 |
1979年 | 80篇 |
1978年 | 92篇 |
1977年 | 68篇 |
1976年 | 76篇 |
1975年 | 76篇 |
1974年 | 68篇 |
1973年 | 67篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
92.
A statement approved "by the Board of Directors on May 29, 1949, and presented on'June 1, 1949, at the annual Conference, Chicago," by, A P. Black, Chairman, Special Committee on A. W. W. A. Policy re Fluoridation of public Water Supplies. 相似文献
93.
Jordan Nunan Ian Stanier Rebecca Milne Andrea Shawyer Dave Walsh Brandon May 《Psychiatry, Psychology and Law》2022,29(1):1
Covert Human Intelligence Sources (CHIS) provide unique access to criminals and organised crime groups, and their collection of intelligence is vital to understanding England and Wales’ threat picture. Rapport is essential to the establishment and maintenance of effective professional relationships between source handlers and their CHIS. Thus, rapport-based interviewing is a fundamental factor to maximising intelligence yield. The present research gained unprecedented access to 105 real-life audio recorded telephone interactions between England and Wales police source handlers and CHIS. This research quantified both the rapport component behaviours (e.g., attention, positivity, and coordination) displayed by the source handler and the intelligence yielded from the CHIS, in order to investigate the frequencies of these rapport components and their relationship to intelligence yield. Overall rapport, attention and coordination significantly correlated with intelligence yield, while positivity did not. Attention was the most frequently used component of rapport, followed by positivity, and then coordination.Key words: Covert Human Intelligence Source, human intelligence, HUMINT, intelligence, interviewing, rapport, source handler 相似文献
94.
Dominik N?rz Susanne Pfefferle Thomas Brehm Gefion Franke Ilka Grewe Birte Knobling Martin Aepfelbacher Samuel Huber Eva M. Klupp Sabine Jordan Marylyn M. Addo Julian Schulze zur Wiesch Stefan Schmiedel Marc Lütgehetmann Johannes K. Knobloch 《Euro surveillance : bulletin européen sur les maladies transmissibles = European communicable disease bulletin》2022,27(26)
95.
Denis G Sukhodolsky Karim Ibrahim Carla B Kalvin Rebecca P Jordan Jeffrey Eilbott Michelle Hampson 《Social cognitive and affective neuroscience》2022,17(7):634
Childhood maladaptive aggression is associated with disrupted functional connectivity within amygdala-prefrontal circuitry. In this study, neural correlates of childhood aggression were probed using the intrinsic connectivity distribution, a voxel-wise metric of global resting-state brain connectivity. This sample included 38 children with aggressive behavior (26 boys, 12 girls) ages 8–16 years and 21 healthy controls (14 boys, 6 girls) matched for age and IQ. Functional MRI data were acquired during resting state, and differential patterns of intrinsic functional connectivity were tested in a priori regions of interest implicated in the pathophysiology of aggressive behavior. Next, correlational analyses tested for associations between functional connectivity and severity of aggression measured by the Reactive-Proactive Aggression Questionnaire in children with aggression. Children with aggressive behavior showed increased global connectivity in the bilateral amygdala relative to controls. Greater severity of aggressive behavior was associated with decreasing global connectivity in the dorsal anterior cingulate and ventromedial prefrontal cortex. Follow-up seed analysis revealed that aggression was also positively correlated with left amygdala connectivity with the dorsal anterior cingulate, ventromedial and dorsolateral prefrontal cortical regions. These results highlight the potential role of connectivity of the amygdala and medial prefrontal and anterior cingulate cortices in modulating the severity of aggressive behavior in treatment-seeking children. 相似文献
96.
David W. Jordan Murray D. Becker Samuel Brady Mary Ann Keenan Max P. Rosen Debapriya Sengupta Keith J. Strauss Dianna D. Cody 《Journal of the American College of Radiology》2019,16(2):236-239
The ACR Dose Index Registry (DIR) provides a new source of clinical radiation exposure data that has not been used previously to establish or update the relative radiation level (RRL) values in the ACR Appropriateness Criteria (AC). The results of a recent review of DIR data for 10 common CT examinations were compared with current ACR AC RRL values for the same procedures. The AC RRL values were previously determined by consensus of members of the AC Radiation Exposure Subcommittee based on reference radiation dose values from the literature (when available) and anecdotal information from individual members’ clinical practices and experiences. For 7 of the 10 examination types reviewed, DIR data agreed with existing RRL values. For 3 of 10 examination types, DIR data reflected lower dose values than currently rated in the AC. The Radiation Exposure Subcommittee will revise these RRL assignments in a forthcoming update to the AC (in October 2018) and will continue to monitor the DIR and associated reviews and analyses to refine RRL assignments for additional examination types. Given recent attention and efforts to reduce radiation exposure in CT and other imaging modalities, it is likely that other examination types will require revision of RRL assignments once information from the DIR database is considered. 相似文献
97.
Results of standard chemotherapy in ovarian cancer are hampered by the development of drug resistance leading to disease recurrence. This prompted interest in the development of therapies targeting critical pathways responsible for tumor progression. Angiogenesis is a key process that enables ovarian cancer growth and metastasis in the peritoneal space. Its regulation relies on signaling mechanisms initiated by the vascular endothelial growth factor, the platelet-derived growth factor, the fibroblast growth factor, angiopoietins, and others. These pathways are not only important to the modulation of the tumor microenvironment and vasculature, but also control cancer cell proliferation and survival. In this review, we discuss preclinical evidence supporting the rationale for inhibiting these pathways and provide an overview for the clinical development of agents targeting them. Clinical trials evaluating such agents alone and in combination with chemotherapy are ongoing. Early clinical results position antiangiogenic therapy at the forefront of change to the standard treatment of difficult to treat ovarian cancer. 相似文献
98.
Enhanced VWF biosynthesis and elevated plasma VWF due to a natural variant in the murine Vwf gene 总被引:4,自引:0,他引:4 下载免费PDF全文
Both genetic and environmental influences contribute to the wide variation in plasma von Willebrand factor (VWF) levels observed in humans. Inbred mouse strains also have highly variable plasma VWF levels, providing a convenient model in which to study genetic modifiers of VWF. Previously, we identified a major modifier of VWF levels in the mouse (Mvwf1) as a regulatory mutation in murine Galgt2. We now report the identification of an additional murine VWF modifier (Mvwf2). Mvwf2 accounts for approximately 16% of the 8-fold plasma VWF variation (or approximately 25% of the genetic variation) observed between the A/J and CASA/RkJ strains and maps to the murine Vwf gene itself. Twenty SNPs were identified within the coding regions of the A/J and CASA/RkJ Vwf alleles, and in vitro analysis of recombinant VWF demonstrated that a single SNP (+7970G>A) and the associated nonsynonymous amino acid change (R2657Q) confers a significant increase in VWF biosynthesis from the CASA/RkJ Vwf allele. This change appears to represent a unique gain of function that likely explains the mechanism of Mvwf2 in vivo. The identification of a natural Vwf gene variant among inbred mice affecting biosynthesis suggests that similar genetic variation may contribute to the wide range of VWF levels observed in humans. 相似文献
99.