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   280478篇
  免费   13340篇
  国内免费   607篇
耳鼻咽喉   3610篇
儿科学   8576篇
妇产科学   6025篇
基础医学   39950篇
口腔科学   6500篇
临床医学   22268篇
内科学   61846篇
皮肤病学   7495篇
神经病学   25507篇
特种医学   8832篇
外国民族医学   108篇
外科学   35030篇
综合类   1340篇
一般理论   72篇
预防医学   25544篇
眼科学   5234篇
药学   19499篇
中国医学   863篇
肿瘤学   16126篇
  2023年   1473篇
  2022年   1715篇
  2021年   4919篇
  2020年   2854篇
  2019年   4979篇
  2018年   9766篇
  2017年   6378篇
  2016年   5828篇
  2015年   6345篇
  2014年   7203篇
  2013年   11162篇
  2012年   18490篇
  2011年   18560篇
  2010年   9605篇
  2009年   7601篇
  2008年   15870篇
  2007年   16890篇
  2006年   15615篇
  2005年   15462篇
  2004年   14502篇
  2003年   13345篇
  2002年   12604篇
  2001年   7288篇
  2000年   7409篇
  1999年   6522篇
  1998年   1455篇
  1997年   1140篇
  1996年   1047篇
  1995年   950篇
  1992年   3727篇
  1991年   3341篇
  1990年   3167篇
  1989年   2917篇
  1988年   2734篇
  1987年   2589篇
  1986年   2443篇
  1985年   2187篇
  1984年   1640篇
  1983年   1404篇
  1979年   1411篇
  1978年   1021篇
  1977年   952篇
  1975年   973篇
  1974年   1149篇
  1973年   1186篇
  1972年   1095篇
  1971年   1082篇
  1970年   998篇
  1969年   1023篇
  1968年   920篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
PURPOSE: Temporomandibular joint (TMJ) arthroscopy has been considered a safe surgical procedure in the treatment of TMJ derangement. However, it is not exempt from complications. This study evaluates the complications of arthroscopy in patients with internal derangement of TMJ. PATIENTS AND METHODS: Five hundred consecutive patients (670 joints) with TMJ derangement who underwent arthroscopy between 1995 and 2004 were retrospectively analyzed. All the patients were classified as II to V in the Wilkes classification. Lysis and lavage, electrocautery of the posterior ligament, injection of corticoids, injection of ethanolamine, myotomy of lateral pterygoid muscle attachments, myotomy and electrocautery, motor debridement, injection of sodium hyaluronate, and meniscal suture were performed in different patients. RESULTS: Complications were recognized during or immediately after the surgery. They were observed in 5 of 341 (1.26%) arthroscopies of the right TMJ and 4 of 329 (1.21%) arthroscopies of the left TMJ. A 1.34% complication rate was found in the whole series. No blood clots within the external auditory canal were observed. Bleeding within the superior TMJ space was observed in 57 cases (8.5%), 36 of them in the right TMJ and 21 in the left TMJ, but they were not considered as true complications. Lacerations of the external auditory canal were found in 2 cases (0.3%), with no cases of perforation of the tympanic membrane. Lesion of the auriculotemporal nerve was observed in a case. Paresia of the facial nerve was found in 4 cases (0.6%). Alteration of visual accuracy of the ipsilateral eye was also observed in a patient immediately after the surgery. CONCLUSION: Special care must be taken to reduce complications within the upper joint space by means of an adequate instrumentation and by paying attention to essential points of the arthroscopic technique.  相似文献   
52.
Experience in the treatment of 129 patients with esophagogastric hemorrhage due to portal hypertension is discussed. An original modification of the design of Blakemore's tube is suggested, with the use of which the results of nonoperative treatment were improved and the mortality among this category of patients was reduced. Operation was performed on 75 patients. The total mortality among all hospitalized patients was 6.2%. The Tanner-Petrov operation was carried out on 55 patients, splenorenal anastomosis was formed in 6, organopexy was conducted on 4, splenectomy in combination with organopexy in 8, and portocaval anastomosis was formed in 2 patients. Three patients died after the operation.  相似文献   
53.
A case of a pedunculated arachnoid cyst within the third ventricle is presented. The cyst was small so as not to appear as a significant expanding lesion on CT. The clinical history, however, suggested intermittent increase of the intracranial pressure. On CT there was some widening of the lateral and third ventricles, while the fourth ventricle had normal width. This finding in combination with the clinical history prompted further neuroradiologic examinations, including pneumoencephalography and ventriculography. The presence of a pedunculated mobile cystic lesion within the third ventricle was shown and its nature further elucidated by stereotactic puncture combined with contrast injection into the cyst. After emptying of the cyst, the patient has been free of symptoms during an observation time of 2 years. The diagnostic and differential diagnostic aspects are discussed and the value of traditional neuroradiologic methods emphasized.  相似文献   
54.
INTRODUCTION: Ischemic heart disease is a major cause of heart failure in western societies. However, the factors that may influence left ventricular function (LVF) recovery after an acute coronary syndrome (ACS) are still unclear. OBJECTIVE: To identify variables that may influence LVF evolution one year after ACS. METHODS: 104 patients hospitalized with ACS between 7/1/2001 and 12/31/2002 and with systolic dysfunction--defined as an echocardiographic ejection fraction (EF) < or = 45%--were randomly allocated to a planned coronary follow-up program (FUP) or a general cardiology clinic (GC); patients from both groups were also randomly referred to a structured cardiac rehabilitation program (CRP). EF was re-assessed at one year. We compared differences between patients who recovered left ventricular function (EF > 45%; group 1) and those who did not (group 2). RESULTS: One year after discharge, 44.2% of the patients had recovered function. There were no significant differences between the groups in gender (77.7 vs. 76.5% male), age (56 vs. 59 years), hypertension, diabetes, dyslipidemia, smoking habits or family history. A previous history of cardiovascular events was more frequent in group 2 (11.1% vs. 35.3%, p = 0.03). Cardiac catheterization was performed before discharge in 88.8% and 88.2% in groups 1 and 2 respectively (p = NS); no differences were found in coronary anatomy between the two groups. Angioplasty was performed in 54.2% in group 1 and 50% in group 2 (p = NS). There were no differences in the use of angiotensin-converting enzyme inhibitors (83.3% vs. 87.5%), beta-blockers (87.5% vs. 87.5%), nitrates (37.5% vs. 33.3%), aspirin (95.8% vs. 95.8%), statins (79.1% vs. 75%) or diuretics (20.8% vs. 45.8%). There was no significant difference in LVF recovery between patients randomized to FUP or GC (38.5% vs. 54.5%). 87.5% of patients who completed the CRP had normal EF at one year compared to 32.7% of patients not referred to the program (p = 0.009). Although EF improved in both groups, this improvement was greater in patients who completed a CRP (EF 8% vs. 5%, p = 0.003). CONCLUSION: A previous cardiovascular event and completion of a CRP were the only variables that influenced LVF recovery. Thus, enrollment in a CRP, in addition to standard therapy, could be an important therapeutic measure in patients with systolic dysfunction after ACS; our data suggest that these programs should be more widely used.  相似文献   
55.
56.
57.
Enoximone is a positive inotropic agent belonging to the group of phosphodiesterase F-III inhibitors. The drug was tested in 34 patients uncontrolled by sympathomimetic drugs and referred to our department for urgent heart transplantation or circulatory assistance. After insertion of a Swan-Ganzgatheter and a radial artery catheter for haemodynamic monitoring, enoximone was administered as a 15-minute intravenous bolus injection of 1 to 2.5 mg/kf every 8 hours, in addition to sympathomimetic agents. Clinical and haemodynamic improvement was observed after thirty minutes in 30 patients. The cardiac index rose from 1.82 to 2.67 l/min/m2 and the pulmonary wedge pressure fell from 30.8 to 18.9 mmHg. Systemic arterial resistance decreased from 2170 to 1520 dyn. s. cm-5, and pulmonary resistance from 5.5 to 4.6 Wood units (p less than 0.01 for all values). Four patients had no haemodynamic improvement and were put on circulatory assistance, using a Jarvik 7 total artificial heart in 3 of them and heterotopic circulatory assistance in one. After clinical investigation for contra-indication to heart transplantation, and as their improved haemodynamic status permitted, 12 of the 30 patients were considered suitable (group B) for heart transplantation. Transplantation was performed within a week of admission in 11 patients without any need for mechanical assistance. One of the group B patients who required implantation of a Jarvik 7 artificial heart died after 12 hours of assistance. Eighteen patients were considered unsuitable for transplantation (group A) and treated medically.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
58.
Many types of seafood require cooking before ingestion and it has been demonstrated that this cooking process may affect the antigenicity and allergenicity of the food. We describe a case of anaphylaxis caused by selective sensitization to razor shell, a mollusc. In vivo and in vitro studies confirmed sensitization to boiled razor shell. Analysis of the nature of the allergen yielded results that were consistent with the findings of other authors and suggested that allergens involved in seafood allergy are commonly high molecular weight proteins that, in most cases, are heat stable.  相似文献   
59.
60.
To produce hybrids, one member of the parental line is genetically made male-sterile. This male-sterile trait is encoded by mitochondria so that it is maternally inherited. Consequently, the progeny of a male-sterile plant is fully sterile. Nevertheless, during the handling of cytoplasmic male-sterile seed stocks, some mixture with seeds of the maintainer lines can occur. Up to the present time, the only way to check the homogeneity of the cytoplasmic male-sterile seed stock was to grow the plants until flowering time. We have developed a method which can be used immediately after the harvest, allowing us to check samples from both sunflower and sugar beet. We used the mitochondrial plasmid, present only in the maintainer lines, as a probe for the total nucleic acids prepared from the cytoplasmic male-sterile seed stocks which might be contaminated. The signals compared to those of samples artificially contaminated allow us to measure as few as one male-fertile seed in 1000 seeds in a rapid and accurate manner.  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