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   102392篇
  免费   4997篇
  国内免费   425篇
耳鼻咽喉   1154篇
儿科学   2521篇
妇产科学   1784篇
基础医学   12499篇
口腔科学   1759篇
临床医学   10724篇
内科学   20394篇
皮肤病学   1341篇
神经病学   10179篇
特种医学   3913篇
外国民族医学   3篇
外科学   16376篇
综合类   1085篇
一般理论   131篇
预防医学   8267篇
眼科学   2090篇
药学   6528篇
  16篇
中国医学   106篇
肿瘤学   6944篇
  2024年   236篇
  2023年   615篇
  2022年   970篇
  2021年   2149篇
  2020年   1426篇
  2019年   2216篇
  2018年   2580篇
  2017年   1830篇
  2016年   1989篇
  2015年   2275篇
  2014年   3445篇
  2013年   4730篇
  2012年   7564篇
  2011年   7975篇
  2010年   4587篇
  2009年   4133篇
  2008年   7125篇
  2007年   7452篇
  2006年   7180篇
  2005年   6897篇
  2004年   6719篇
  2003年   6051篇
  2002年   5708篇
  2001年   839篇
  2000年   558篇
  1999年   891篇
  1998年   1219篇
  1997年   926篇
  1996年   748篇
  1995年   682篇
  1994年   589篇
  1993年   578篇
  1992年   441篇
  1991年   399篇
  1990年   322篇
  1989年   292篇
  1988年   277篇
  1987年   277篇
  1986年   241篇
  1985年   279篇
  1984年   307篇
  1983年   254篇
  1982年   333篇
  1981年   281篇
  1980年   221篇
  1979年   93篇
  1978年   128篇
  1977年   108篇
  1976年   78篇
  1973年   69篇
排序方式: 共有10000条查询结果,搜索用时 46 毫秒
91.
92.
Recent media depictions of the dangers of biomedical research have fueled public and regulatory scrutiny of academic research institutions. The authors argue that if these institutions are to preserve the trust that the public has historically bestowed upon them, they must go beyond mere compliance with regulatory mandates. Several steps are suggested that institutions can take to strengthen and supplement ongoing compliance efforts, steps the authors believe will bolster the public's confidence in the integrity of academic research institutions. These steps grow out of the authors' analysis of three key components of institutional trustworthiness: (1) shared goals between research institutions and the communities they serve, (2) robust institutional oversight of research activities, and (3) training programs that build professional character. The authors' recommendations include the use of research advisory councils to assure the public that research goals reflect community interests, more collaborative relationships between institutional review boards and members of investigative teams, and educational programs that emphasize the importance of professional integrity in biomedical research. These efforts will help preserve public confidence that an institution's research priorities are appropriate and that the research it conducts is ethical. Preserving this public trust is central to the long-term success of biomedical research and the institutions in which such research takes place.  相似文献   
93.
1. The pharmacokinetics of Dalal-peptide T-NH2 (peptide T) was determined during phase I clinical trials in patients with acquired immunodeficiecy disease (AIDS) and AIDS related complex (ARC). Drug levels were determined by specific RIA, and in some cases with HPLC analysis, after intraveneous (i.v.) or intranasal (i.n.), via metered sprayer, administration.

2. The plasma kinetics appeared to be bi-phasic with a first compartment half-life of 30 to 60 minutes and a second plasma clearence rate of 4 to 6 hours, observed for both routes of administration. Peptide T, in one individual was confirmed to be present at 6 hrs in plasma, determined after HPLC isolation followed by specific RIA.

3. Bioavailabilty, determined for a 2 mg test dose in six individuals was 9.3 ± 6.9 nmol/L. Peak plasma levels of 41 ± 30 nmol/L after 10 mg i.n., 2.8 ± 5.9 nmol/L after 2mg i.n., and 0.13 ± 0.07 nmol/L after 0.4 mg i.n. were observed. In two individuals tested, peptide T was detected in CSF at levels 20% of the corresponding plasma level 90 and 145 minutes post i.v. administration. Peptide T was not detected in urine. I.N. administration was well tolerated for times up to 21 months.  相似文献   

94.
A case of true conversive hallucinations in a 19-year-old female soldier is described. This phenomenon is rare and should be distinguished from psychotic or dissociative states.  相似文献   
95.
Perceived control of asthma and quality of life among adults with asthma.   总被引:3,自引:0,他引:3  
BACKGROUND: Perceived control of certain chronic conditions influences health status outcomes. OBJECTIVE: To explore the impact of perceived control of asthma on asthma-specific and generic health status outcomes among adults with asthma. Perceived control was defined as individuals' perceptions of their ability to deal with asthma and its exacerbations. METHODS: Data were drawn from the baseline and first two followups of a longitudinal study of adults with asthma surveyed by telephone at 18-month intervals. An 11-item questionnaire (Perceived Control of Asthma Questionnaire [PCAQ]) was developed and validated. RESULTS: The PCAQ demonstrated high internal consistency (Cronbach's alpha = 0.79). Greater perceived control was associated with less severe asthma, greater asthma self-efficacy, lower perceived asthma severity, lower perceived danger from asthma, and greater perceived usefulness of asthma medicines. Greater perceived control was significantly associated with better asthma-specific quality of life concurrently and 18 and 36 months later, after controlling for demographics, smoking, and severity of asthma. Greater perceived control as also significantly associated with generic mental health outcomes concurrently and 18 and 36 months later, after controlling for covariates. Perceived control was associated with physical function concurrently and 18 months later, but not 36 months later. CONCLUSIONS: The PCAQ is a reliable and valid measure of perceived control of asthma. Perceived control of asthma was associated with both asthma-specific and generic health status outcomes, concurrently and predictively. If perceived control could be modified, better outcomes, particularly better psychologic outcomes, might be achieved for individuals with asthma.  相似文献   
96.
97.
Objectives/Hypothesis: Vocal rehabilitation of patients who have undergone laryngectomy is best accomplished by a tracheoesophageal puncture. Optimal function of the prosthesis requires an adequate stoma. Patients with tracheostomal stenosis require revision of the stoma if vocal rehabilitation is to take place. Revision and tracheoesophageal placement are usually done as two separate procedures. Creating a tracheoesophageal fistula at the time of stomal revision has not been addressed in the literature. Study Design: Prospective analysis and follow-up of 10 patients undergoing simultaneous tracheoesophageal puncture and stomal revision for tracheostomal stenosis between 1991 and 1996. Methods: Ten patients were reviewed. An inferiorly based V-Y advancement flap was used so as not to interfere with the tracheoesophageal puncture. All patients had received radiation prior to revision and tracheoesophageal puncture. Patients were followed for a minimum of 2 years (range, 2–6 y; median, 3 y). Results: All patients maintained an adequate stoma without stenting. Eight of ten patients (80%) developed and maintained good tracheoesophageal speech. Two patients had their speech fistulas removed. There were no intraoperative or postoperative complications. Conclusions: Creation of a tracheoesophageal fistula at the time of stomal revision allows for vocal rehabilitation with a single visit to the operating room. Laryngoscope, 108:1509-1513, 1998  相似文献   
98.
The purpose of this study was to evaluate the influence of composition and deformation of biomedical stainless steels on mechanical properties, magnetic properties, and MRI artifacts. Type 304 and Type 316L samples were prepared using standard wire-drawing techniques. Mechanical properties were determined using standard test methods. The amount of ferromagnetic phase present was estimated using a Severn Gage and x-ray diffraction. Magnetic field attraction and artifacts were determined using previously described techniques. The strength of both steels increased significantly with increasing deformation. None of the type 316L wires transformed to the magnetic phase. The amount of magnetic phase in the type 304 wires increased with increasing deformation. There was no magnetic field attraction, and artifacts were minimal for all of type 316L wires and the undeformed type 304 wire. Deflection and artifacts were significant for the deformed type 304 stainless steel. These results provide guidance regarding the use of type 304 and type 316L stainless steels for bioimplants. In this regard, type 316L stainless steel seems to be a more acceptable material with respect to MR compatibility.  相似文献   
99.
100.
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