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   29997篇
  免费   2162篇
  国内免费   909篇
耳鼻咽喉   456篇
儿科学   380篇
妇产科学   481篇
基础医学   1948篇
口腔科学   1501篇
临床医学   3078篇
内科学   3135篇
皮肤病学   647篇
神经病学   1087篇
特种医学   1230篇
外国民族医学   4篇
外科学   8337篇
综合类   4476篇
现状与发展   3篇
预防医学   1419篇
眼科学   412篇
药学   2004篇
  41篇
中国医学   961篇
肿瘤学   1468篇
  2024年   98篇
  2023年   630篇
  2022年   1143篇
  2021年   1430篇
  2020年   1411篇
  2019年   1198篇
  2018年   1120篇
  2017年   1091篇
  2016年   1216篇
  2015年   1193篇
  2014年   2208篇
  2013年   2085篇
  2012年   1754篇
  2011年   2033篇
  2010年   1734篇
  2009年   1444篇
  2008年   1391篇
  2007年   1347篇
  2006年   1155篇
  2005年   1008篇
  2004年   829篇
  2003年   710篇
  2002年   519篇
  2001年   418篇
  2000年   400篇
  1999年   344篇
  1998年   329篇
  1997年   270篇
  1996年   227篇
  1995年   249篇
  1994年   234篇
  1993年   190篇
  1992年   170篇
  1991年   177篇
  1990年   159篇
  1989年   128篇
  1988年   140篇
  1987年   107篇
  1986年   109篇
  1985年   109篇
  1984年   102篇
  1983年   66篇
  1982年   104篇
  1981年   52篇
  1980年   64篇
  1979年   36篇
  1978年   32篇
  1977年   29篇
  1976年   25篇
  1974年   17篇
排序方式: 共有10000条查询结果,搜索用时 10 毫秒
81.
Between 1983 and 1993, 41 patients underwent a first-stage Belt-Fuqua operation for penile hypospadias repair and 39 completed the second stage. Minor complications were observed after the first stage. The primary success rate following the second stage was 82%. Major complications noted after the second stage consisted mainly of fistula formation. The surgical technique is described and alternative methods are discussed.  相似文献   
82.
In this study we have investigated the effects of breath holding and of the physical properties of gases on four different respiratory dead spaces (V D): the Fowler, the physiological, the washout and the inert gas dead space. The experiments were performed with dogs which were ventilated artifically with breathing patterns with different post-inspiratory breath holding times (t a) of 0, 0.5, 1.0 and 2.0 s. Tracer amounts of acetone, ether and enflurane were infused continuously into a peripheral vein and a bolus of a mixture of krypton, Freon12 and SF6 was introduced into the peritoneal cavity. After reaching steady state, samples of arterial blood, mixed venous blood and mixed expired air were taken simultaneously. From the partial pressures (P a, P ¯V and P respectively) we determined the excretion (=P/P¯V), retention (R=Pa/P¯V) and the physiological dead space fraction (V D,phys/V T=(1 P/Pa) for each gas, where V T is tidal volume. Further, we recorded the expirograms of the six tracer gases and of CO2 from which the Fowler dead space fractions (V D,Fowler/V T) of the different gases were determined. Also the washout dead space fractions (V D,washout/V T) for He and SF6 were determined as well as the inert gas dead space fraction (V D,MIGET/V T) with the use of the multiple inert gas elimination technique (MIGET).With the exception of V D,phys/V T for SF6, all dead space fractions decreased with increasing t a. V D,phys/V T for the poorly soluble gas SF6 was considerably larger than V D,phys/V T for the remaining gases. For the highly soluble acetone V Fowler/V T was considerably smaller than V D,Fowler/V T for the other gases. V D,washout,SF6/V T was always larger than V D,washout,He/V T and V D,Fowler,SF6/V T. Further, V D,phys/V T was larger than V D,Fowler/V T for SF6 and acetone. However, for gases with intermediate solubility in blood V D,phys/V T tended to be smaller than V D,Fowler/V T. We conclude that the respiratory dead spaces are affected by the breathing pattern and by the physical properties of gases, i.e. their diffusivity in alveolar gas and their solubility in blood or lung tissue.  相似文献   
83.
Since its conception, several techniques have been described for laparoscopic appendicectomy. We describe a technique which utilizes a 5-mm bipolar forceps designed to coagulate and cut tissues at the same time; 50 pediatric patients underwent laparoscopic appendicectomy for acute appendicitis using this stripping and teasing technique. No bleeding complications occurred. There were only two postoperative abscesses in the series. We believe that the bipolar laparoscopic striptease appendicectomy technique as developed by the senior author is safe, quick, and effective, even for severe appendicitis.  相似文献   
84.
85.
86.
Mega-Liposuction: Analysis of 1520 Patients   总被引:1,自引:0,他引:1  
Fifteen hundred and twenty cases of liposuction/liposculpture were performed at Dr. M. Erfan & Bagedo Hospitals and King Abdulaziz University Hospital in Jeddah from January 1983 to December 1994. These cases were mostly females. The age group was from 16–65 years. Multiple procedures were performed in 11.68% of these cases. The change in hemoglobin and the hematocrit ratio pre- and post-operatively, and the incidence of complications, were studied. The percentage of surface area operated upon rather than the amount of fat removed was the most important relevant factor.  相似文献   
87.
The aim of our study was to evaluate the validity of a quantitative US technique for measuring the bone density of the proximal phalanges of the nondominant hand compared with computed metacarpal radiogrammetry and dual-photon absorptiometry (DPA) of the lumbar spine. Mean US bone velocity (UBV) correlated with mean metacarpal cortical index (MCI), with mean metacarpal bone density (MBD) and with bone mineral density (BMD) of the lumbar spine, whereas it was correlated negatively with age and menopause duration. The average UBV was significantly higher in premenopausal women than in postmenopausal women, and higher in normal lumbar DPA patients than in reduced lumbar DPA patients. We conclude that the US evaluation of the nondominant hand proximal phalanges may be a new alternative way for measuring bone mass in screening of osteoporosis. Correspondence to: A. Sili Scavalli  相似文献   
88.
Background: For a long time, surgeons hesitated to extract more than 2.5 liters of adipose tissue from a patient. Through the years, liposuction has advanced, now allowing megaliposculptures to be performed so that more than 10 liters can be extracted without posing any greater risk to the patient than a conventional esthetic liposculpture. Methods: This article traces the progressive evolution of the technique, discussing complications and the concept of megaliposculpturing. Results: The syringe-assisted extraction of large quantities of adipose tissue without transfusion, hypovolemic shock, or any major complication opens new horizons in the symptomatic treatment of certain types of osteoarthritis of the lower extremities and the potential complications of obesity. Conclusions: Large quantities of adipose tissue may safely, quickly and efficiently be extracted. Numerous investigations in various pathological domains can now begin after this first step (megalipotherapy). Therapeutic megalipoextraction can be done either as a preliminary indication or as a treatment of the residual adiposities that occur after bariatric operations.  相似文献   
89.
Summary The cortical imaging technique (CIT), a mathematical method for simulating the potential fields on the surface of the brain, was used to analyze the spatio-temporal progression of the AEP P300 component (as well as the preceding and subsequent N2a and N3 components) from thirty normal adult subjects recorded in a standard oddball paradigm. Comparisons were made between the progressions of the endogenous event-related cognitive potentials and the exogenous stimulus-dependent potentials (Nl component). Cortical imaging results suggest that different and multiple generator sites are involved in the production of exogenous and endogenous evoked responses. We particularly note the asymmetric development of the P300 component and the apparent anterior generator sites for the N2a component. This last result is interesting because the N2a precedes the P300 component and supports an earlier frontal contribution.  相似文献   
90.
Intra-anal intussusception was diagnosed in eight of 39 patients on evacuation proctography. Posteroanterior views revealed prolapse of the infolded rectum into the anal canal on straining in seven of eight patients, associated with splaying open of the anal canal and sudden distal movement of the fold during prolapse. Similar changes were seen in four of 31 patients in whom intussusception had not been diagnosed on lateral evacuation proctography. The pattern of the collapsed rectum was assessed for fold length, thickness, and angulation in relation to the midline of the rectum. Infoldings that prolapsed were closer to the anorectal junction on stress (mean 14.6 42.4 mm, p < 0.0001) showed greater change in height between rest and strain (28.8 14.6 mm, p < 0.05) and became more acutely angled during straining (41.9 5.3°, p < 0.01). Intra-anal intussusception may be missed in 33% (four of 12 patients) on routine evacuation proctography. Posteroanterior stress proctography is a simple supplementary examination to validate intussusception.  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