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   873317篇
  免费   58316篇
  国内免费   1858篇
耳鼻咽喉   11435篇
儿科学   28480篇
妇产科学   21122篇
基础医学   133021篇
口腔科学   27227篇
临床医学   76098篇
内科学   171679篇
皮肤病学   20501篇
神经病学   63424篇
特种医学   31223篇
外国民族医学   101篇
外科学   125104篇
综合类   16145篇
现状与发展   4篇
一般理论   221篇
预防医学   68362篇
眼科学   19568篇
药学   64435篇
  3篇
中国医学   3153篇
肿瘤学   52185篇
  2021年   9154篇
  2019年   8904篇
  2018年   12642篇
  2017年   9692篇
  2016年   10311篇
  2015年   11751篇
  2014年   15930篇
  2013年   22376篇
  2012年   31441篇
  2011年   32866篇
  2010年   18621篇
  2009年   17113篇
  2008年   28586篇
  2007年   30677篇
  2006年   30279篇
  2005年   29146篇
  2004年   28143篇
  2003年   26325篇
  2002年   24027篇
  2001年   40656篇
  2000年   41276篇
  1999年   34267篇
  1998年   9335篇
  1997年   7875篇
  1996年   8128篇
  1995年   7621篇
  1994年   7078篇
  1993年   6486篇
  1992年   25377篇
  1991年   25245篇
  1990年   24438篇
  1989年   24205篇
  1988年   21945篇
  1987年   21212篇
  1986年   20116篇
  1985年   18888篇
  1984年   13861篇
  1983年   11671篇
  1982年   6454篇
  1979年   12379篇
  1978年   8692篇
  1977年   7284篇
  1976年   6976篇
  1975年   7779篇
  1974年   9015篇
  1973年   8652篇
  1972年   8095篇
  1971年   7499篇
  1970年   7303篇
  1969年   6734篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
Volume and profile of alcohol consumption among students and classmates as predictors of aggression and victimization: a multilevel analysis among Swiss adolescents

Objective:  

To test the effects of the volume of alcohol consumption and drinking patterns on alcohol-related aggression and victimization, both at the individual and class levels.  相似文献   
42.
Complex regional pain syndrome (CRPS) was formerly known as “Sudeck’s atrophy”. The disease belongs to the group of neuropathic pain syndromes and is differentiated into three types. Type I is characterized by a lack of nerve lesions, type II by the presence of nerve lesions, and type III by the presence of other entities such as fibromyalgia. The exact pathogenic factors leading to the disease are still unknown and are currently the subject of investigation in various studies. These studies suggest a contribution of the central nervous system to the development and maintenance of CRPS. However, the clinical symptoms are well documented and include pain, autonomic changes and impaired motor function of the affected extremity. Diagnosis is based clinically on signs and symptoms. However, in a few cases radiography and scintiscanning may be useful to finalize the diagnosis. The treatment options are centred on the symptoms of pain, autonomic changes and functional impairment. A multidisciplinary treatment strategy is recommended, with surgeons, anaesthesiologists, physiotherapists and psychotherapists working together. Surgical intervention in this disease is only required in rare cases of neurological and bone pain, and the indications for such intervention are narrow and should be strictly observed.  相似文献   
43.
There are no data available combining transbronchial needle aspiration (TBNA) of mediastinal lymph nodes and positron emission tomography (PET) in the staging of nonsmall cell lung cancer (NSCLC). The aim of the current study was to determine if these two methods can enhance the negative predictive value of the individual modality alone, for a specific lymph node station, and if this integrated approach can reduce the number of mediastinoscopies. A total of 113 patients with enlarged mediastinal lymph nodes (> or = 1 cm), who underwent both TBNA and PET scanning, were included. In 51 patients, histopathology, confirmed by surgical lymph node dissection, was compared with PET results and TBNA. Sensitivity, specificity, positive predictive value, negative predictive value and accuracy to detect malignant lymphadenopathy was 68 (13/19), 89 (119/134), 46 (13/28), 95 (119/125) and 86% (132/152) for PET, respectively; 54% (6/11), 100 (53/53), 100 (6/6), 91 (53/58) and 92% (59/64), respectively for TBNA; and 100 (11/11), 94 (50/53), 79 (11/14), 100 (50/50) and 95 (61/64) for combined TBNA and PET, respectively. Combination of transbronchial needle aspiration and positron emission tomography has the potential to allow adequate mediastinal staging of nonsmall cell lung cancer with enlarged lymph nodes in most patients without the need for mediastinoscopy.  相似文献   
44.
Scarifications are frequently seen in the passage from adolescence to adulthood. Their nosographic context has expanded to include defensive behavior in reaction to the difficulties of assuming autonomy, or those associated with separation, to an attempt to express acute anxiety in borderline states or in certain cases of psychosis.The transition to adulthood is a particularly exacting period for girls. In a society that places value upon visual appearance, the bodily changes that take place during puberty and the occurrence of the first menstruations are often a traumatic experience, and may temporarily inhibit the acceptance of womanhood. Self-mutilations constitute a corporal limit that may facilitate the adolescent's acceptance of the bodily change towards full femininity.As in the myth of Narcissus, scarifications or superficial cutaneous incisions are a means of providing the possibility of withdrawal into oneself; in an attempt to control underlying tension and anxiety the adolescent voluntarily causes blood to appear and disappear through self-mutilation, so that it is no longer perceived as a menace. Scarifications therefore allow girls an appropriation of the female body, and thus may be a means of their coming to terms with the metamorphosis that is taking place. This hypothesis has been illustrated through a specific case history.  相似文献   
45.
Abstract Chorea is a rare complication of polycythaemia vera. Polycythaemic chorea occurs predominantly in females and usually in generalised form. We present a 66-year-old woman with acute onset hemichorea-ballism with no vascular pathology in the basal ganglia region. A clear relationship was observed between the onset of chorea and worsening of haematological parameters in the patient. After repeated phlebotomies the patient's clinical status was improved. Polycythaemic chorea must be considered, especially in the elderly, as early diagnosis leads to effective treatment and prevention of complications.  相似文献   
46.
Intraoperative and postoperative free flap monitoring by means of oxygen tension measurement was carried out in 11 patients. We used an invasive flexible microcatheter that allowed for measurement of oxygen tension in all types of free flaps. Two cases of the measured flaps were buried free flaps which do not allow monitoring by clinical assessment. All flaps monitored in this study survived. One case of displacement of the microcatheter occurred. In one patient, the tissue pO2 monitor successfully detected early vascular thrombosis with subsequent reoperation and salvage of the free flap.  相似文献   
47.
This study was performed to evaluate the surgical strategy in patients with calvarial tumours, in order to design and modify a robot-assisted trepanation system. A total of 75 patients underwent craniectomy for the treatment of calvarial tumours during the 10-year period from 1993 to 2002. The patients' complaints, the size, location and histology of the tumour, and the various cranioplasty techniques used were analysed retrospectively. In a second procedure several craniectomies at typical locations according to the study's results were performed in a laboratory setting using a hexapod robotic tool, constructed at the Helmholtz-Institute, RWTH Aachen University, and plastic model heads. The workflow was documented and the reproducibility and the accuracy of the procedure were registered. A total of 83 surgical procedures were performed on 75 patients. The majority (87 %) of lesions treated surgically were located in the frontal, temporal and anterior parts of the parietal region. Histological examination revealed benign lesions in 66 % of the patients and dural involvement in 46 %. According to these results craniectomies were performed using the robotic system. Mean positioning accuracy of the robotic system while milling was 0.24 mm, with a standard deviation of 0.04 mm, and maximum error under 1 mm. Craniectomies leaving a 1-mm layer of the tabula interna intact to ensure a healthy dura were performed in several regions successfully. The majority of calvarial tumours, requiring surgical treatment in our patients, were located in cosmetically relevant areas in which drilling can be carried out with the robotic trepanation system. Consequently, the surgical approach had to be planned carefully in order to achieve a good cosmetic outcome.  相似文献   
48.
This article describes a modified suture technique designed for the vertical repair of the anterior horn of the meniscus after arthroscopic decompression of a large meniscal cyst. This procedure comprises of three steps: first, the meniscus was pierced vertically using a suture hook and a No. 0 PDS suture. Second, both ends of the No. 0 PDS on the femoral and tibial surfaces of the meniscus were pulled to the outside of the joint capsule using a spinal needle preloaded with suture material. Finally, a skin incision was made adjacent to the suture materials, and both ends were tied. We recommend this technique not only for the vertical repair of the anterior horn of the meniscus after decompression of large meniscal cyst, but also to repair a longitudinal tear of the meniscus.  相似文献   
49.
For many parents stopping life-sustaining medical treatment on their dying infant is psychologically impossible. Dostoevsky's insights into human behavior, particularly the fact that individuals do not want the anxiety and guilt associated with responsibility for making difficult decisions, might change the way physicians approach parents for permission to withdraw life-prolonging medical interventions on dying infants.  相似文献   
50.
A series of 1-alkyl-3,4-dihydroisoquinolines and the related 4-alkyl-1,2-dihydro-benzo[f]isoquinolines was synthesized using reactions of dialkylbenzylcarbinols and their naphthyl analogs with alkylcyanides. Experiments showed that 1-alkyl-6,7-dimethoxy-3,4-dihydroisoquinolines typically produce a hypotensive action, while the benzo-annelated structures usually exhibit a hypertensive effects. The most active compound decreases the arterial pressure in cats by 52 Torr and the effect lasts for about 4 hours. __________ Translated from Khimiko-Farmatsevticheskii Zhurnal, Vol. 40, No. 3, pp. 15–17, March, 2006.  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