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   3787780篇
  免费   301397篇
  国内免费   14705篇
耳鼻咽喉   50819篇
儿科学   120270篇
妇产科学   97950篇
基础医学   591665篇
口腔科学   102381篇
临床医学   340487篇
内科学   675174篇
皮肤病学   98932篇
神经病学   317122篇
特种医学   147219篇
外国民族医学   262篇
外科学   582362篇
综合类   114360篇
现状与发展   23篇
一般理论   2362篇
预防医学   311198篇
眼科学   89705篇
药学   261748篇
  26篇
中国医学   11473篇
肿瘤学   188344篇
  2021年   55920篇
  2020年   35579篇
  2019年   58629篇
  2018年   73027篇
  2017年   55706篇
  2016年   61693篇
  2015年   75323篇
  2014年   109691篇
  2013年   175129篇
  2012年   105324篇
  2011年   107283篇
  2010年   121119篇
  2009年   123960篇
  2008年   93550篇
  2007年   98199篇
  2006年   107476篇
  2005年   102211篇
  2004年   103851篇
  2003年   93751篇
  2002年   83067篇
  2001年   136320篇
  2000年   129873篇
  1999年   122174篇
  1998年   68631篇
  1997年   65296篇
  1996年   63015篇
  1995年   58555篇
  1994年   52555篇
  1993年   48910篇
  1992年   85146篇
  1991年   81055篇
  1990年   76761篇
  1989年   75218篇
  1988年   69102篇
  1987年   67278篇
  1986年   63601篇
  1985年   62840篇
  1984年   54940篇
  1983年   49627篇
  1982年   43636篇
  1981年   41004篇
  1980年   38467篇
  1979年   44920篇
  1978年   38282篇
  1977年   34959篇
  1976年   31992篇
  1975年   30835篇
  1974年   32532篇
  1973年   31243篇
  1972年   29084篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
991.
992.
993.
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   
994.
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   
995.
BACKGROUND: Adrenocortical carcinoma (ACC) is a rare and highly malignant tumour with a poor prognosis. Patients present with signs of steroid hormone excess (e.g., Cushing's syndrome) or symptoms due to an abdominal mass. DIAGNOSIS: In case of an adrenal mass, hormonal workup before surgery is required for differential diagnosis, perioperative management, and for follow-up. The imaging of choice is CT or MRI with MRI being of additional use when invasion of big vessels is suspected. Apart from that, the use of 18-FDG-PET is becoming increasingly established. TREATMENT: Surgical resection is the therapeutic option of choice in stages 1 - 3. In stage 4, the adrenolytic compound mitotane is part of the first-line treatment, but often needs to be combined with cytotoxic chemotherapy. Most patients will eventually have a recurrence, so adjuvant treatment (mitotane/tumour bed radiation) has to be considered in high risk patients, even if randomized controlled trials on adjuvant treatment are still lacking. STRUCTURAL PROGRESS: Several national and European structures have recently been established in order to increase our knowledge of ACC, improve therapeutic options and diagnostic procedures, and promote research. GANIMED, as a Germany-wide network of experts on adrenal diseases, has been founded allowing for improved gathering of data and joint studies. ENSAT (European Network for the Study of Adrenal Tumours) has been brought to life, aiming at European standards for therapy, diagnosis and tumour banking. Since 2003, patients can be enrolled in the German ACC Registry. France and Italy have also developed a central registry to collect nationwide data from patients with ACC. For the first time, patients with metastatic/unresectable ACC can participate in a prospective controlled randomized trial comparing two different cytotoxic chemotherapy regimes (FIRM-ACT).  相似文献   
996.
The present study compared four different sites and conditions for the measurement of maximal inspiratory pressure (MIP) and maximal expiratory pressure (MEP) in 38 spontaneous breathing tracheotomised patients. Of the patients, 28 had chronic obstructive pulmonary disease (COPD). The four different conditions were: 1) through a cuff inflated cannula (condition A); 2) through the mouth with a deflated cannula (condition B); 3) through the mouth with a phonetic uncuffed cannula (condition C); and 4) through the mouth after stoma closure (condition D). Five trials in each condition were performed using a standardised method. The measurement of both MIP and MEP differed significantly depending on the condition of measurement. MIP taken in condition A was significantly higher when compared with conditions B, C and D. MEP in condition A was significantly higher when compared with condition B and D. In condition A the highest frequency of the best measurement of MIP and MEP was observed at the fourth and fifth effort, respectively. The same results were obtained after the selection of only COPD patients. In conclusion, respiratory muscle assessment differs significantly depending on measurement condition. Measurement through inflated cannula tracheotomy yields higher values of both maximal inspiratory and maximal expiratory pressure.  相似文献   
997.
998.
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   
999.
1000.
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