首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   10535篇
  免费   801篇
  国内免费   35篇
耳鼻咽喉   80篇
儿科学   308篇
妇产科学   300篇
基础医学   1455篇
口腔科学   234篇
临床医学   1307篇
内科学   2070篇
皮肤病学   259篇
神经病学   1131篇
特种医学   189篇
外科学   929篇
综合类   77篇
一般理论   16篇
预防医学   1340篇
眼科学   183篇
药学   711篇
中国医学   32篇
肿瘤学   750篇
  2023年   121篇
  2022年   93篇
  2021年   456篇
  2020年   264篇
  2019年   365篇
  2018年   380篇
  2017年   275篇
  2016年   320篇
  2015年   326篇
  2014年   400篇
  2013年   594篇
  2012年   855篇
  2011年   842篇
  2010年   486篇
  2009年   386篇
  2008年   648篇
  2007年   638篇
  2006年   583篇
  2005年   552篇
  2004年   467篇
  2003年   453篇
  2002年   403篇
  2001年   47篇
  2000年   44篇
  1999年   49篇
  1998年   86篇
  1997年   78篇
  1996年   67篇
  1995年   60篇
  1994年   49篇
  1993年   49篇
  1992年   35篇
  1991年   43篇
  1990年   40篇
  1989年   28篇
  1988年   35篇
  1987年   38篇
  1986年   33篇
  1985年   33篇
  1984年   36篇
  1983年   43篇
  1982年   40篇
  1981年   47篇
  1980年   46篇
  1977年   22篇
  1976年   17篇
  1975年   16篇
  1974年   17篇
  1973年   18篇
  1970年   19篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
The UK has low breastfeeding rates, with socioeconomic disparities. The Assets‐based feeding help Before and After birth (ABA) intervention was designed to be inclusive and improve infant feeding behaviours. ABA is underpinned by the behaviour change wheel and offers an assets‐based approach focusing on positive capabilities of individuals and communities, including use of a Genogram. This study aimed to investigate feasibility of intervention delivery within a randomised controlled trial (RCT). Nulliparous women ≥16 years, (n = 103) from two English sites were recruited and randomised to either intervention or usual care. The intervention – delivered through face‐to‐face, telephone and text message by trained Infant Feeding Helpers (IFHs) – ran from 30‐weeks' gestation until 5‐months postnatal. Outcomes included recruitment rates and follow‐up at 3‐days, 8‐weeks and 6‐months postnatal, with collection of future full trial outcomes via questionnaires. A mixed‐methods process evaluation included qualitative interviews with 30 women, 13 IFHs and 17 maternity providers; IFH contact logs; and fidelity checking of antenatal contact recordings. This study successfully recruited women, including teenagers, from socioeconomically disadvantaged areas; postnatal follow‐up rates were 68.0%, 85.4% and 80.6% at 3‐days, 8‐weeks and 6‐months respectively. Breastfeeding at 8‐weeks was obtained for 95.1% using routine data for non‐responders. It was possible to recruit and train peer supporters to deliver the intervention with adequate fidelity. The ABA intervention was acceptable to women, IFHs and maternity services. There was minimal contamination and no evidence of intervention‐related harm. In conclusion, the intervention is feasible to deliver within an RCT, and a definitive trial required.  相似文献   
2.
3.
G protein-coupled estrogen receptor-1 (GPER), a member of the G protein-coupled receptor (GPCR) superfamily, mediates estrogen-induced proliferation of normal and malignant breast epithelial cells. However, its role in breast cancer stem cells (BCSCs) remains unclear. Here we showed greater expression of GPER in BCSCs than non-BCSCs of three patient-derived xenografts of ER/PR+ breast cancers. GPER silencing reduced stemness features of BCSCs as reflected by reduced mammosphere forming capacity in vitro, and tumor growth in vivo with decreased BCSC populations. Comparative phosphoproteomics revealed greater GPER-mediated PKA/BAD signaling in BCSCs. Activation of GPER by its ligands, including tamoxifen (TMX), induced phosphorylation of PKA and BAD-Ser118 to sustain BCSC characteristics. Transfection with a dominant-negative mutant BAD (Ser118Ala) led to reduced cell survival. Taken together, GPER and its downstream signaling play a key role in maintaining the stemness of BCSCs, suggesting that GPER is a potential therapeutic target for eradicating BCSCs.  相似文献   
4.
5.
6.
Abstract

This article follows up a pilot project to help educate local nurses and patient educators on freely available consumer health resources. The Outreach Coordinator and Clinical Librarian at an academic medical center created a one-hour in-person and online class with continuing education credit and an online guide. Nurses frequently act as patient educators at the bedside and are therefore an important target for consumer health education. While nurses in an urban setting may have more access to educational opportunities, these opportunities are needed even more in rural settings. Librarians can obtain funding to travel and teach classes at rural community hospitals.  相似文献   
7.
The fat mass and obesity-associated gene (FTO) rs9939609 A-allele is linked to obesity and dyslipidemia, yet the independent influence of this polymorphism on blood lipids remains equivocal. We examined the influence of the FTO rs9939609 polymorphism on fasting and postprandial blood lipids in individuals homozygous for the risk A-allele or T-allele with similar anthropometric and demographic characteristics. 12 AA and 12 TT males consumed a standardized meal after fasting overnight. Blood samples were collected at baseline (−1.5 h), before the meal (0 h), and for five hours postprandially to measure lipid, glucose, and insulin concentrations. Time-averaged total area under the curve (TAUC) values (0–5 h) were calculated and compared between genotypes. Fasting triacylglycerol (TG), high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, total cholesterol, non-esterified fatty acid (NEFA), glucose, and insulin concentrations were similar between groups (p ≥ 0.293). TAUC for TG was similar in AAs and TTs (95% confidence interval (CI) −0.52 to 0.31 mmol/L/h; p = 0.606). Likewise, TAUC values were similar for NEFA (95% CI −0.04 to 0.03 mmol/L/h; p = 0.734), glucose (95% CI −0.41 to 0.44 mmol/L/h; p = 0.951), and insulin (95% CI −6.87 to 2.83 pmol/L/h; p = 0.395). Blood lipids are not influenced by the FTO rs9939609 polymorphism, suggesting the FTO-dyslipidemia link is mediated by adiposity and weight management is important in preventing FTO-related lipid variations.  相似文献   
8.
9.
OBJECTIVE: To determine the age at which infants achieve velopharyngeal closure during vocalization. DESIGN: Longitudinal with repeated measures. SETTING: Laboratory. PARTICIPANTS: Six healthy infants were studied monthly from ages 2 to 6 months while they interacted with a parent and an investigator. MAIN OUTCOME MEASURES: The presence or absence of velopharyngeal closure, as determined by sensing ram pressure at the anterior nares. RESULTS: The velopharynx was open for windups, whimpers, and laughs, and it was closed for cries, screams, and raspberries, regardless of age. The frequency with which the velopharynx closed during syllable utterances increased significantly with age. CONCLUSIONS: Velopharyngeal closure for speech-like utterance increases with age, but is not complete and is still undergoing development at 6 months of age. Velopharyngeal closure during infancy may be influenced by pressure demands of the utterance; however, support for this speculation is stronger for other types of utterances than it is for speech-like utterances. The method used in this study holds promise for evaluating infants with suspected velopharyngeal impairment.  相似文献   
10.
When the entire body of dogs was exposed to 450 units of Roentgen irradiation a hemorrhagic syndrome developed which was characterized by thrombo-cytopenia, prolonged clotting and bleeding times, and neutropenia. The prothrombin time remained normal until about 24 hours before death. The calcium, phosphorus, and magnesium levels were not altered. Fibrinogen was present but syneresis was poor. Toluidine blue and protamine sulfate, substances which can inhibit the biologic action of heparin, restored the clotting time to normal. The hemorrhagic state was not materially altered by transfusions, vitamin K, or vitamin C. Toluidine blue and protamine sulfate were ineffective in the control of hemorrhage produced by dicumarol. The defect responsible for bleeding after irradiation appeared to be the presence in the circulation of an anticoagulant whose properties, so far as tested, were indistinguishable from those of heparin.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号