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   18076篇
  免费   1120篇
  国内免费   91篇
耳鼻咽喉   143篇
儿科学   483篇
妇产科学   584篇
基础医学   2383篇
口腔科学   638篇
临床医学   1137篇
内科学   3954篇
皮肤病学   346篇
神经病学   1416篇
特种医学   587篇
外国民族医学   1篇
外科学   2671篇
综合类   179篇
一般理论   8篇
预防医学   1306篇
眼科学   382篇
药学   1115篇
中国医学   78篇
肿瘤学   1876篇
  2023年   79篇
  2022年   205篇
  2021年   449篇
  2020年   279篇
  2019年   356篇
  2018年   467篇
  2017年   339篇
  2016年   380篇
  2015年   442篇
  2014年   604篇
  2013年   816篇
  2012年   1169篇
  2011年   1153篇
  2010年   738篇
  2009年   631篇
  2008年   1002篇
  2007年   989篇
  2006年   927篇
  2005年   859篇
  2004年   876篇
  2003年   806篇
  2002年   823篇
  2001年   529篇
  2000年   463篇
  1999年   433篇
  1998年   213篇
  1997年   173篇
  1996年   167篇
  1995年   159篇
  1994年   132篇
  1993年   115篇
  1992年   252篇
  1991年   232篇
  1990年   219篇
  1989年   225篇
  1988年   176篇
  1987年   140篇
  1986年   160篇
  1985年   130篇
  1984年   106篇
  1983年   87篇
  1982年   68篇
  1981年   56篇
  1979年   62篇
  1975年   38篇
  1974年   43篇
  1973年   42篇
  1969年   39篇
  1968年   43篇
  1967年   38篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
21.
As assessed by both standard histological staining and immunochemistry, intraperitoneal inoculation of C. burnetii in guinea pigs led to pathologic changes mainly in the liver, whereas intranasal inoculation led to pathologic changes mainly in the lungs. Myocarditis and positive blood cultures were observed only in those animals which received the highest inoculum. We therefore conclude that both the route of infection and the size of the inoculum influence clinical expression in acute Q fever.  相似文献   
22.
The effects of sedative-hypnotic doses of propofol on respiratory drive and pattern have not yet been extensively described. Repeated small boluses of propofol (0.6-0.3 mg.kg-1) were administered to ten ASA I patients undergoing carpal tunnel release using regional anaesthesia. Airway pressure, capnography and pneumotachography were continuously recorded. With respect to basal values, no significant variations of respiratory rate, minute volume, tidal volume, inspiratory and expiratory time, total expiratory cycle, Ti/Ttot, TV/Ti, P0.1, EtCO2 and blood gas analysis were observed. Low doses of propofol, to maintain conscious sedation of light sleep, have not been shown to cause respiratory depression.  相似文献   
23.
24.
25.
BACKGROUND. The relation between body mass index and acute myocardial infarction was analyzed using data from a multicentric case-control study conducted in Italy between September 1988 and June 1989 within the framework of the GISSI-2 trial. METHODS. Subjects were 916 patients with acute myocardial infarction and no history of cardiovascular disease and 1,106 controls hospitalized for acute conditions not related to known or suspected risk factors for ischaemic heart disease. RESULTS. Relative to the lowest quintile of the Quetelet Index (weight/height2) the estimated risks for subsequent quintiles were 1.2 (95% confidence intervals, (CI): 0.9 to 1.6), 1.7 (95% CI: 1.2 to 2.2), 1.8 (95% CI: 1.4 to 2.4), and 2.2 (95% CI: 1.7 to 3.0) when adjustment was made for age, sex, education, and smoking habits by means of logistic regression. The association was consistent across strata of sex, education, and smoking status, but not age. The estimated risk for subjects in the fifth quintile of the Quetelet Index relative to those in the first was 4.1 under 55 years of age, but only 1.7 between 55 and 64 years and 1.5 above age 65. CONCLUSION. The relation between body mass and myocardial infarction was explained, at least in part, by higher serum cholesterol levels and the prevalence of diabetes and hypertension among fatter subjects. This does not, however, totally eclipse a possible causal relation between body mass and risk of myocardial infarction, since these conditions are a consequence, rather than a confounder, of overweight.  相似文献   
26.
27.
A discussion of the present role of varicocele in the management of the subfertile couple is presented, with emphasis on detection techniques and the increasing awareness of the presence of bilateral varicocele. The indications and techniques of surgical management are discussed, with particular emphasis on the use of the operating microscope to dissect the spermatic cord at the level of the external inguinal ring under local anesthesia on an outpatient basis with significant cost savings to the patient.  相似文献   
28.
Purpose  To present a case of brainstem anaesthesia as a complication of peribulbar anaesthesia. Clinical features  A 75-yr-old woman received peribulbar anaesthesia for cataract surgery. A few seconds after the block was performed, she had a respiratory arrest, became unconscious, and developed hypertension and tachycardia followed by hypotension and bradycardia. Ventilatory and haemodynamic support were performed before the patient regained adequate spontaneous breathing and normal heart rate and blood pressure. Conclusion  Peribulbar anaesthesia generally cames a low risk of serious complications. However, respiratory arrest and brainstem anaesthesia may occur as complications of peribulbar blocks.
Résumé Objectif  Présenter un cas d’anesthésie du tronc cérébral compliquant une anesthésie péribulbaire. éléments cliniques  Un bloc péribulbaire était réalisé chez une femine de 75 ans pour l’extraction d’une cataracte. Quelques secondes après l’injection, la patiente cessait de respirer et perdait conscience. Elle devenait hypertendue et tachycarde puts hypotendue et bradycarde. La ventilation et la circulation devaient être supportées jusqu’au retour spontané à la normale. Conclusion  En général, l’anesthésie péribulbare comporte un faible risque de complications sérieuses. Un arrêt respiratoire par anesthésie du tronc cérébral est toujours possible.
  相似文献   
29.
A study was carried out to analyse trends in cancer mortality sex differentials. This study compared age-standardized sex ratio values for mortality from 18 cancers (or groups of cancers), and total cancer mortality over the period 1950-1989 in 24 European countries, for 4 age groups (all ages, 20-44 years, 45-64 years, and 65 years and over). For lung cancer and other tobacco-related neoplasms, appreciable rises in sex ratio values were observed until the late 1970s, particularly in Southern and Eastern Europe, before levelling off in recent years, particularly among the younger age groups. In the late 1980s, the range of variation in overall age-standardized sex ratios for lung cancer was between 2 and 3 in the United Kingdom and in Nordic countries, and around or over 10 in Southern Europe. In young adults, the decline in sex ratio values observed in Denmark and Sweden (unity), and in other Nordic countries and in the United Kingdom (around or below 2) reflects a levelling of lung cancer in young males and an increase in young females. This clearly indicates that young women are a priority target group for smoking control interventions in Europe. Appreciable cohort effects were also observed for stomach cancer: rises in sex ratio values were greater in, or restricted to, middle- and older age groups, whereas in the young there was some tendency towards a levelling in sex differentials. The overall sex ratio values for stomach cancer were around 2 in most areas of Europe in the late 1980s. For intestinal cancer, sex ratio values showed some tendency to rise, reaching a level of 1.3-1.7 in the late 1980s; steady rises were also registered in sex ratio values for melanoma (skin cancer), reaching 1.5-1.8 in the late 1980s in most countries. These upward trends which were minor or inconsistent at younger ages in several countries became progressively stronger with advancing age. Sex ratio values were below unity for cancers of the gallbladder and the thyroid. Sex ratio values tended to rise also for leukaemia (from 1.2-1.5 to 1.5-1.7), but showed no noticeable trend for lymphomas or myeloma. The overall sex ratio values for total cancer mortality in the 1950s were between 1.2 and 1.4 in most European countries. Thereafter, they rose appreciably in several countries, reaching 1.9 in Czechoslovakia, Italy and Poland, and 2.3 in France.(ABSTRACT TRUNCATED AT 400 WORDS)  相似文献   
30.
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