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   935334篇
  免费   66601篇
  国内免费   1346篇
耳鼻咽喉   12978篇
儿科学   24484篇
妇产科学   23357篇
基础医学   133489篇
口腔科学   28500篇
临床医学   80890篇
内科学   183762篇
皮肤病学   19282篇
神经病学   72491篇
特种医学   36890篇
外国民族医学   79篇
外科学   152603篇
综合类   18055篇
现状与发展   1篇
一般理论   240篇
预防医学   62036篇
眼科学   21328篇
药学   72840篇
  3篇
中国医学   2166篇
肿瘤学   57807篇
  2018年   9041篇
  2017年   7092篇
  2016年   7836篇
  2015年   8925篇
  2014年   12053篇
  2013年   17642篇
  2012年   24226篇
  2011年   25141篇
  2010年   14891篇
  2009年   14352篇
  2008年   24739篇
  2007年   25815篇
  2006年   26601篇
  2005年   25563篇
  2004年   24646篇
  2003年   23734篇
  2002年   23267篇
  2001年   54812篇
  2000年   56640篇
  1999年   47051篇
  1998年   10784篇
  1997年   9518篇
  1996年   9631篇
  1995年   8961篇
  1994年   8309篇
  1993年   7642篇
  1992年   35602篇
  1991年   34024篇
  1990年   32841篇
  1989年   31960篇
  1988年   29065篇
  1987年   28325篇
  1986年   26370篇
  1985年   25203篇
  1984年   17899篇
  1983年   15191篇
  1982年   7823篇
  1981年   6796篇
  1979年   15826篇
  1978年   10638篇
  1977年   9088篇
  1976年   7904篇
  1975年   8656篇
  1974年   10501篇
  1973年   9896篇
  1972年   9381篇
  1971年   8880篇
  1970年   8448篇
  1969年   7936篇
  1968年   7218篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
Gallstone dissolution   总被引:2,自引:0,他引:2  
Many methods are available for gallstone dissolution, including oral bile salts; cholesterol solvents such as mono-octanoin or methyl tert-butyl either; and calcium or pigment solvents such as EDTA and polysorbate. Which of these approaches will be appropriate for an individual patient depends on the type of stones; whether they are in the gallbladder or the bile ducts; whether access to the biliary tree is available; the patient's age and general medical condition; and the availability of necessary expertise. In the US, both chenodeoxycholate and ursodeoxycholate are now available. Ursodeoxycholate is more expensive but appears to produce fewer side effects and may be more efficacious. These agents are most effective in thin women with small floating, radiolucent cholesterol stones in a functioning gallbladder. Only about half of the small subset of patients will experience partial or complete dissolution of stones within a year. Stone recurrence and the potential toxicity of long-term therapy are problems with this approach. Therefore, for most patients, cholecystectomy, either in the traditional fashion or using a laparoscopic approach (see article later in this issue by Gadacz et al), is the most cost-effective and perhaps the safest option. Intragallbladder instillation of methyl tert-butyl ether probably will be applicable only to a small subset of patients, and treatment is likely to be followed by a high recurrence rate. In patients with retained common duct cholesterol stones and access to the biliary tree, mono-octanoin therapy is advantageous in that it can be initiated as soon as cholangiography demonstrates no extravasation. In properly selected patients, a 90% success rate with this technique can be expected within 7 days.  相似文献   
82.
Patients on long-term haemodialysis suffer from dialysis arthropathy due to the deposition of dialysis amyloid. We investigated the use of 99Tc-labelled methylene diphosphonate bone scans in 17 patients as a possible in vivo diagnostic technique. In most clinically affected joints, with the exception of shoulders and hands, there was increased radioisotope uptake consistent with uptake by periarticular bone. In addition, we describe intense soft-tissue uptake around some clinically affected large joints. In contrast, control groups of patients on haemodialysis without arthropathy and patients without renal failure did not have increased uptake. A semi-quantitative scale of uptake was devised, and the following correlations were significant: pain perception and isotope uptake score in the ankles and feet, and the number of radiological lesions and isotope uptake scores in the wrists and knees. The following sites where the radioisotope might bind in the affected joints are proposed: amyloid deposits, areas of soft-tissue calcification, or areas of increased bone turnover. It is concluded that whereas the scanning technique cannot make a definite diagnosis of amyloid and, therefore, cannot be expected to supersede histological diagnosis, it is a useful adjuvant investigation, of particular importance in those patients unable or unwilling to undergo biopsy.  相似文献   
83.
Eleven patients with lunatomalacia were treated by excision of the lunate and instillation of liquid silicone. The silicone vulcanised and formed an in-situ molded prosthesis. The patients were reexamined after a mean of 7.1 years. Four patients were pain-free and two had pain only at work; three had not been improved by the operation and two had undergone arthrodesis. The patients with good results all belonged to group IV pre-operatively. Surprisingly, no patient showed any sign of silicone synovitis, although all the prostheses except one had either fractured or deformed. The reasons for this are discussed and the indications for the operation established.  相似文献   
84.
85.
Excision of the rectum should take in account that the main lymphatic spread follows the cranial route and that dissection of the rectal wall should be performed across its adjacent anatomical lamellae. It is not clear whether an extensive pelvic dissection and high ligature of the inferior mesenteric artery are beneficial. Spontaneous or iatrogenic perforation of the tumour considerable increases the incidence of local recurrence. The frequency of postoperative urinary and sexual dysfunction ranges from 3.5-57% and 14-38% respectively. The reported surgical mortality averages 5-6%.  相似文献   
86.
Summary A case of bilateral congenital pseudarthrosis of the clavicle in a baby boy is described. The patient is fully asymptomatic, and no functional impairment is present. This is probably only the seventh case described of this rare congenital anomaly.  相似文献   
87.
Regional effects of craniotomy on cerebral circulation and metabolism, such as regional cerebral blood flow (rCBF), regional cerebral oxygen consumption (rCMRO2), regional oxygen extraction fraction (rOEF), and regional cerebral blood volume (rCBV) were examined by a PET (positron emission tomography) study concerning surgery that was performed on unruptured aneurysm patients. Eight patients with intracranial un-ruptured aneurysms were studied pre- and post-operatively by the 15O labelled-gas steady-state method, using HEADTOME-III. All patients underwent aneurysmal surgery performed by the transsylvian approach. There was a significant increase in the mean OEF values taken from the whole-brains of 8 patients, but there was not a significant change in CBF, CMRO2 or CBV. The increase in OEF was caused by decrease of O2 content, which was caused by post-operative decrease in the Hb value. So, this OEF increase was not the direct effect of craniotomy. In 2 patients, the rCBF and rCMRO2, in the fronto-temporal region (where craniotomy was performed) increased post-operatively. This regional effect suggests transient reactive hyperemia following compressive ischemia during the operative procedure, and metabolic demands for recovery of brain function. In 2 other patients, who had relatively low rCBFs during the pre-operative study, rCBF and rCMRO2 in the bi-frontal region had decreased more at the post-operative study. This change appears to have been caused by removal of cerebrospinal fluid and depression of the frontal lobe. From this study, it becomes evident that the regional effect of craniotomy on cerebral circulation and metabolism is not so great, when adequate microsurgical techniques are used.  相似文献   
88.
89.
90.
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