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   3530368篇
  免费   295213篇
  国内免费   14165篇
耳鼻咽喉   47901篇
儿科学   112575篇
妇产科学   92338篇
基础医学   561134篇
口腔科学   93796篇
临床医学   317237篇
内科学   629417篇
皮肤病学   93288篇
神经病学   303811篇
特种医学   137854篇
外国民族医学   490篇
外科学   541119篇
综合类   107624篇
现状与发展   24篇
一般理论   2337篇
预防医学   297064篇
眼科学   80596篇
药学   241597篇
  22篇
中国医学   10471篇
肿瘤学   169051篇
  2021年   55163篇
  2020年   35129篇
  2019年   58148篇
  2018年   71605篇
  2017年   54710篇
  2016年   60480篇
  2015年   74342篇
  2014年   108570篇
  2013年   173661篇
  2012年   98887篇
  2011年   99373篇
  2010年   117839篇
  2009年   122231篇
  2008年   86184篇
  2007年   89801篇
  2006年   100267篇
  2005年   95550篇
  2004年   96980篇
  2003年   87424篇
  2002年   76886篇
  2001年   118110篇
  2000年   111567篇
  1999年   107512篇
  1998年   66639篇
  1997年   64233篇
  1996年   62074篇
  1995年   57522篇
  1994年   51464篇
  1993年   48034篇
  1992年   74191篇
  1991年   69865篇
  1990年   65607篇
  1989年   64402篇
  1988年   59365篇
  1987年   58076篇
  1986年   54614篇
  1985年   54411篇
  1984年   49485篇
  1983年   45057篇
  1982年   42165篇
  1981年   39542篇
  1980年   37232篇
  1979年   40221篇
  1978年   35565篇
  1977年   32274篇
  1976年   29611篇
  1975年   27937篇
  1974年   29005篇
  1973年   28026篇
  1972年   26228篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
161.
Liver disease alters the pharmacokinetic and pharmacodynamic properties of hepatically eliminated drugs. The main factors influenced are plasma albumin levels, enzyme balance (induction & inhibition) and drug binding to tissue proteins. The influence of lidocaine on serum, heart and liver propranolol levels in Wistar rats after liver injury induced by carbon tetrachloride CCl4 0.4 ml/kg x 2/wkl, was investigated. 40 male Wistar rats were divided into four groups (I, II, III, IV; n=10), Group I animals received only propranolol (labelled + cold substance) 40 mg/kg/12 h p.o., group II propranolol plus lidocaine in a single dose of 4mg/kg s.c., group III was treated with CCl4 for 6 weeks and received propranolol x2 at the same dosage as group I, while group VI was treated with CCl4 and the same drug dosage as group II. The simultaneous administration of H3-propranolol and lidocaine increased propranolol levels in the serum and tissues. The liver in damaged animals showed an increase of propranolol level under lidocaine co-administration, probably due to CCl4 induced liver enzyme activity, resulting in a rapid propranolol metabolism or to competition between both drug protein binding sites. The increased propranolol levels in the heart after lidocaine administration were probably due to attributed to its high affinity for heart tissue. Consequently, as regards the therapeutic approach for patients with liver disease receiving propranolol their propranolol dosage should be reduced when lidocaine is co-administered.  相似文献   
162.
Coronary magnetic resonance angiography (CMRA) is a technique in clinical evolution. Current clinical applications include assessment for coronary anomalies, aneurysms, bypass graft patency, and, in experienced centers, the exclusion of proximal and multivessel coronary artery disease (CAD). As local expertise increases and more extensive multicenter data become available, additional applications will be established. CMRA promises to supplement and in some cases obviate the need for X-ray contrast angiography, and to expand our understanding of the pathophysiology of CAD. Zusammenfassung Die Magnetresonanzangiographie der Koronargefäße (CMRA) ist eine sich ständig weiterentwickelnde Technik. Etablierte Anwendungen sind zurzeit die Beurteilung von koronaren Anomalien, Aneurysmen und der Durchgängigkeit von Bypasses. Auch der Ausschluss proximaler Koronarstenosen und einer koronaren Mehrgefäßerkrankung ist in einigen spezialisierten Zentren möglich. Mit zunehmender Erfahrung der jeweiligen Anwender und der Verfügbarkeit von Ergebnissen großer multizentrischer Studien können zukünftig weitere klinische Anwendungen etabliert werden. In der Zukunft könnte die CMRA ergänzende Informationen zur Indikationsstellung einer konventionellen Röntgenangiographie bringen und in einigen Fällen diese Untersuchung sogar ersetzen. Die CMRA wird unseren Einblick in die Pathophysiologie der koronaren Herzerkrankung sicher erweitern.  相似文献   
163.
The overnight one-mg dexamethasone suppression test has been used for many years to screen for Cushing's syndrome. This test has usually been evaluated in controls versus patients with severe hypercortisolism. Under these conditions, the overnight dexamethasone suppression test has been reported to have high sensitivity and specificity. The objective of this study was to determine the sensitivity of the one mg overnight dexamethasone suppression test in patients with mild and/or periodic Cushing's syndrome. Therefore, an overnight dexamethasone suppression test was performed in 17 consecutive patients presenting to an endocrinology clinic with signs and symptoms of hypercortisolemia who were later proven to have Cushing's syndrome. The majority of patients were found to have both mild and periodic hypercortisolism. One mg of dexamethasone was given at midnight and a plasma cortisol was measured by radioimmunoassay at 08:00 the following morning. Using a cut-off for a morning cortisol following overnight dexamethasone of > 5 microg/dL, only three of 17 patients failed to suppress to a value less than this cut-off (sensitivity 18 %). A cut-off of > 2 microg/dL gave similar sensitivity. Even with a stringent cut-off point of > 1.8 microg/dL, only seven of 17 patients failed to suppress to a value less than this cut-off point (sensitivity of 41 %). These results demonstrate that the great majority of patients with mild and/or periodic Cushing's syndrome suppress to overnight dexamethasone. Since patients with mild and/or periodic Cushing's syndrome are the patients in whom the identification of hypercortisolism is difficult, our results from this relatively small study suggest that this test should no longer be used to exclude these patients from further workup for Cushing's syndrome.  相似文献   
164.
165.
背景/目的:从1978-2000年,有10对联体双胞胎成功接受了手术分离,结果14人存活。其中6对是因为他们的联体同胞死亡或濒临死亡而接受紧急分离手术。剩余的4对,每对至少一个同胞接受至少一次的急诊手术后,才接受联体分离手术。方法:对这一独特的队列进行包含6个项目的问卷调查。问题的设计是开放式的,为父母/家庭提供有关信息的最大机会。对每个家庭就相同的问题也进行了当面的问卷调查。医师询问了与身体健康和疾病相关的一些问题。而社会工作询问了与发育、教育、社会心理和家庭功能相关的问题。结果:前面提及的14人存活的双胞胎中,4人大学毕业,1人于1981年完成中学学业,剩余9人正在上学。14人在最初的手术后,还需要接受再次手术,尤其是需要矫正泌尿系统、畸形、神经外科和小儿外科的问题。结论:通过超声检查对联体双胎进行宫内诊断,可以使医师和胎儿父母在孕早期决定在终止妊娠时是进行双胎分离还是保全其中一个。这些病例报道通过描述14例手术存活的长期体格检查和心理学检查结果,为医师和父母在关键时刻做出决定提供了另外有助的依据。  相似文献   
166.
167.
168.
169.
Although psychoanalysis was the first-choice treatment for premature ejaculation (PE) between 1920 and 1960, hardly any reports on its efficacy have been published. Moreover, a scientific debate about its findings has never been fully developed. The recent progress that has been made in the classification of three different PE syndromes creates a new opportunity for psychoanalytic investigations of men with complaints of PE, distinguished by the actual duration of their intravaginal ejaculation latency time (IELT). The term premature-like ejaculatory dysfunction has been introduced to distinguish men with self-perceived PE at normal and long IELT durations from those men with lifelong, acquired and normal variable PE. Psychoanalytic research may contribute to a better understanding of the consequences of objective early ejaculations on the unconscious mental life of men with the four forms of PE. By integrating neurobiological, clinical and epidemiological data of ejaculatory performance, a revival of psychoanalytic research of PE in the four distinct, classified PE groups, will probably contribute to a deeper insight in to the unconscious mental life of men affected by PE.  相似文献   
170.
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