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   306651篇
  免费   17648篇
  国内免费   439篇
耳鼻咽喉   4534篇
儿科学   11187篇
妇产科学   10625篇
基础医学   45624篇
口腔科学   8104篇
临床医学   24969篇
内科学   57435篇
皮肤病学   6645篇
神经病学   21782篇
特种医学   11999篇
外国民族医学   43篇
外科学   49201篇
综合类   7821篇
现状与发展   1篇
一般理论   166篇
预防医学   20183篇
眼科学   7268篇
药学   21450篇
中国医学   856篇
肿瘤学   14845篇
  2019年   2391篇
  2018年   3905篇
  2017年   2909篇
  2016年   3370篇
  2015年   3727篇
  2014年   4913篇
  2013年   7729篇
  2012年   9715篇
  2011年   10297篇
  2010年   6556篇
  2009年   5778篇
  2008年   9271篇
  2007年   10265篇
  2006年   10098篇
  2005年   9791篇
  2004年   9383篇
  2003年   8838篇
  2002年   8407篇
  2001年   13595篇
  2000年   13995篇
  1999年   11619篇
  1998年   3103篇
  1997年   2841篇
  1996年   2685篇
  1995年   2576篇
  1994年   2362篇
  1992年   8332篇
  1991年   8463篇
  1990年   8268篇
  1989年   8080篇
  1988年   7319篇
  1987年   7075篇
  1986年   6723篇
  1985年   6519篇
  1984年   4760篇
  1983年   4122篇
  1982年   2471篇
  1979年   4435篇
  1978年   3237篇
  1977年   2734篇
  1976年   2508篇
  1975年   2834篇
  1974年   3359篇
  1973年   3363篇
  1972年   3120篇
  1971年   2948篇
  1970年   2839篇
  1969年   2581篇
  1968年   2540篇
  1967年   2373篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
951.
Summary The technique of antidromic mapping with a roving array of electrodes was used to demonstrate that lamina I trigeminothalamic cells responsive specifically to skin temperature project to the n. submedius (Sm) in the medial thalamus of the cat. This finding indicates that Sm receives thermoreceptive in addition to nociceptive information.  相似文献   
952.
Abstract: This open clinical study was aimed at testing the hypothesis that an intravascular oxygenator (IVOX) may help to perform permissive hypoventilation in 10 patients with severe ARDS. After initial evaluation, we tried to reduce ventilator settings before and after IVOX implantation. Before IVOX, poor clinical tolerance and worsening oxygenation did not allow for a significant decrease in ventilator settings. With IVOX, peak inspiratory pressure (PIP) was reduced from 47 to 39 cm H2O (p = 0. 005) and minute ventilation from 13 ± 3. 5 to 11 ± 3 L/min. CO2 removal by IVOX allowed a significant decrease in Paco2 from 66 ± 15 to 59 ± 13 mm Hg. Improvement of oxygenation with IVOX was not signify cant. Furthermore, interruption of oxygen flow through IVOX did not change oxygenation variables. Tolerance of the IVOX device was good, but insertion of the device was followed by a significant decrease in both cardiac index and pulmonary wedge pressure. In conclusion, IVOX improves tolerance of hypoventilation by limiting hypercapnia in ARDS patients. These preliminary results must be confirmed by a randomized controlled study  相似文献   
953.
OBJECTIVE: The authors determined the most useful predictors of common bile duct (CBD) stones as diagnosed by endoscopic retrograde cholangiopancreatography (ERCP) in patients who underwent laparoscopic cholecystectomy (LC). METHODS: Prospective and retrospective collection of historical, biochemical and ultrasonographic data was used. Receiver operating characteristics curve analysis was used to determine optimal biochemical cut-off values. Multivariate analysis using logistic regression with generation of the best model identifying independent predictors of CBD stones also was employed. Prospective validation of the model was performed on an independent group of patients. RESULTS: Endoscopic retrograde cholangiopancreatographies were performed before LC in 106 patients, and after LC in 33. Only four of ten clinical variables evaluated independently predicted the presence of CBD stones. The optimal model predicted a 94% probability of CBD stones in a patient older than 55 years of age who presented with an elevated bilirubin (over 30 mumol/L) and positive ultrasound findings (a dilated CBD, and a CBD stone seen on ultrasound). This model was validated prospectively in a subsequent series of 49 patients in which the probability of CBD stone was only 8% when all four predictors were absent. CONCLUSIONS: The identified independent clinical predictors of a CBD stone helps select a population of symptomatic gallstone bearers who benefit most from cholangiographic assessment.  相似文献   
954.
955.
The effect of vitamin E on halothane-induced liver damage was studied in guinea pig halothane hepatitis. Twenty animals were divided into 3 groups, consisting of a control group, a halothane group and a vitamin E + halothane (H) group. The animals in the control group (n = 6) were allowed to inhale air only. The animals in the halothane group (n = 6) and the vitamin E + H group (n = 8) were allowed to inhale 1% halothane with air. Animals in the vitamin E + H group were additionally injected with 30 mg kg-1 of vitamin E 30 minutes prior to inhalation of halothane. Blood was aspirated from the heart immediately after sacrificing to measure the serum activity of glutamic oxaloacetic transaminase (GOT) and glutamic pyruvic transaminase (GPT). A microsomal suspension was prepared from the excised liver. Then the amount of thiobarbituric acid (TBA) reactive products in the microsomes were measured. The amount of tissue TBA-reactive products was increased by inhalation of halothane. The increase in the amount of TBA-reactive product was inhibited by the administration of vitamin E. The serum GPT activity was increased by halothane inhalation. Increased serum GOT and GPT activity were inhibited by the administration of vitamin E. These results demonstrated that vitamin E suppressed halothane-induced liver damage in the guinea pig by inhibiting lipid peroxidation.  相似文献   
956.
Free hydrocortisone, hydrocortisone incorporated into microspheres and empty microspheres have been administered orally to rats with carrageenan-induced hindpaw inflammation. Hydrocortisone administered in particles was effective at a lower dose than free steroid in reducing inflammation. Inflammatory exudates were able to release steroid from the microspheres by proteolytic degradation.  相似文献   
957.
The infusion of hypertonic solution is thought by the authors to be effective due to its reflectory action for treatment of patients who are in the state of anaphylactic and cardiogenic shock. This method seems to be expedient for massive blood loss under conditions of prehospital medical aid to victims with very low level of arterial pressure, with craniocerebral trauma and critical trauma of the chest.  相似文献   
958.
The activity of nitroxide synthetase (NOS) was studied histochemically and levels of oxytocin and vasopressin immunocytochemically in rat hypothalamus paraventricular nuclei in on-earth experiments simulating space flight conditions with landing. Colonization of oxytocin and NOS was found in large-cell neurons of paraventricular nuclei. After 15 days under conditions of simulated microgravitation followed by 1-day double gravitation and a short-term (1 day) macrogravitation, activities of NOS and content of neuropeptides increased in large-cell neurons of paraventricular nuclei of experimental animals. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 125, No. 3, pp. 282–284, March, 1998  相似文献   
959.
EFE is a rare cardiac disorder with poor prognosis and uncertain cause. Primary and secondary forms have been described. Most authors consider that all EFE is secondary--a reactive process set off in the endocardium by stress on the myocardium. We report two cases representing the primary dilated form and the secondary contracted form. The dilated form was associated with intracavitary thrombus of the left ventricle. In both cases, an unusual presence of subendocardial calcifications was noted. The ultrasonographic findings are discussed.  相似文献   
960.
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