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   18721篇
  免费   1612篇
  国内免费   47篇
耳鼻咽喉   142篇
儿科学   504篇
妇产科学   486篇
基础医学   2464篇
口腔科学   372篇
临床医学   2118篇
内科学   4036篇
皮肤病学   435篇
神经病学   1805篇
特种医学   438篇
外科学   1873篇
综合类   344篇
一般理论   23篇
预防医学   2386篇
眼科学   301篇
药学   1168篇
中国医学   36篇
肿瘤学   1449篇
  2023年   187篇
  2022年   286篇
  2021年   574篇
  2020年   345篇
  2019年   466篇
  2018年   518篇
  2017年   380篇
  2016年   422篇
  2015年   457篇
  2014年   583篇
  2013年   869篇
  2012年   1233篇
  2011年   1198篇
  2010年   717篇
  2009年   558篇
  2008年   982篇
  2007年   1043篇
  2006年   994篇
  2005年   945篇
  2004年   844篇
  2003年   778篇
  2002年   687篇
  2001年   338篇
  2000年   325篇
  1999年   267篇
  1998年   165篇
  1997年   158篇
  1996年   131篇
  1995年   136篇
  1994年   97篇
  1993年   120篇
  1992年   260篇
  1991年   240篇
  1990年   217篇
  1989年   184篇
  1988年   215篇
  1987年   189篇
  1986年   187篇
  1985年   174篇
  1984年   130篇
  1983年   138篇
  1982年   90篇
  1981年   92篇
  1980年   90篇
  1979年   86篇
  1978年   101篇
  1976年   71篇
  1975年   79篇
  1973年   114篇
  1970年   77篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
3.
4.
5.
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   
6.
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   
7.
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   
8.
9.
Objective: The study goal was to compare the laser spot size created using reflective and refractive micromanipulators with a CO2 laser and to determine the sensitivity of spot size to laser power. Study Design and Setting: A CO2 laser and operating microscope (400-mm focal length) was coupled to either a reflective (Cassegrain-like) or refractive micromanipulator. Laser spot size was determined by measuring the region of ablation created by laser irradiation of wood (dry tongue depressors), exposed photographic film, and agar gel using optical micrometry. Laser power varied from 0.5 to 20 W with pulse durations of 0.1 and 0.5 second. Results: The reflective micromanipulator demonstrated overall smaller spot sizes for a given laser power and lower incremental change in spot size with increasing power. The reflective design demonstrated less sensitivity to increases in laser power. Conclusions: Micromanipulator optical design can result in significant differences in laser spot size. The reflective device used in this study demonstrated less sensitivity to increasing laser power. (Otolaryngol Head Neck Surg 2002;126:593-597.)  相似文献   
10.
Heparin-induced Extracorporeal LDL-Precipitation (HELP) is an effective procedure for the elimination of both plasma LDL and fibrinogen. In 10 adult patients with severe type II hyperlipoproteinemia, a single HELP treatment of 3 1 plasma led to an acute decrease in the average plasma viscosity (PV) from 1.30 to 1.1 mPas. At the same time, an even more marked decrease in the mean erythrocyte aggregation rate from a pathological value of 7.9% to a value of 3.7% (normal range less than 5%) was observed. Long-term studies on five patients demonstrated a lasting improvement in these two haemorheological variables. The acute rheological changes were also accompanied by an improvement in polarographically determined muscle oxygen tension. Mean oxygen tension values measured in both the m.biceps brachii and the m.tibialis anterior in five patients before and after a single HELP treatment increased from 30 +/- 4 to 37 +/- 7 mmHg and from 27 +/- 2 to 31 +/- 3 mmHg respectively. These results may provide an explanation for the rapid improvement in patients' clinical symptoms such as angina pectoris and in stress electrocardiogram which have been observed during HELP therapy.  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