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   3433251篇
  免费   250110篇
  国内免费   9210篇
耳鼻咽喉   46434篇
儿科学   113194篇
妇产科学   95732篇
基础医学   481770篇
口腔科学   94765篇
临床医学   314706篇
内科学   673959篇
皮肤病学   81392篇
神经病学   282399篇
特种医学   130818篇
外国民族医学   1111篇
外科学   512424篇
综合类   74067篇
现状与发展   7篇
一般理论   1334篇
预防医学   267575篇
眼科学   77706篇
药学   248338篇
  8篇
中国医学   7249篇
肿瘤学   187583篇
  2019年   27433篇
  2018年   38483篇
  2017年   29552篇
  2016年   33955篇
  2015年   38246篇
  2014年   53278篇
  2013年   79999篇
  2012年   106750篇
  2011年   113260篇
  2010年   67880篇
  2009年   64791篇
  2008年   105321篇
  2007年   111725篇
  2006年   113570篇
  2005年   109278篇
  2004年   104783篇
  2003年   101031篇
  2002年   97605篇
  2001年   165400篇
  2000年   169454篇
  1999年   142492篇
  1998年   41215篇
  1997年   36702篇
  1996年   36720篇
  1995年   35517篇
  1994年   32421篇
  1993年   30342篇
  1992年   110011篇
  1991年   105601篇
  1990年   102326篇
  1989年   98572篇
  1988年   90427篇
  1987年   88583篇
  1986年   82969篇
  1985年   79403篇
  1984年   59539篇
  1983年   50465篇
  1982年   30174篇
  1981年   26904篇
  1979年   52625篇
  1978年   37246篇
  1977年   31388篇
  1976年   29242篇
  1975年   30829篇
  1974年   36713篇
  1973年   35094篇
  1972年   32985篇
  1971年   30503篇
  1970年   28346篇
  1969年   26992篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
941.
Nine hundred and three patients undergoing diagnostic peritoneal lavage (DPL) over a 6-year period were retrospectively reviewed to evaluate the utility of the white blood cell (WBC) count in the lavage fluid. Eleven patients (1.2%) had dialysate WBC counts greater than 500/mm3, with erythrocyte counts less than 10(5)/mm3. Nine of these patients who were lavaged within 4 hours of injury had no intra-abdominal pathology. Two patients, lavaged after 4 hours, demonstrated intra-abdominal injury. Two hundred twenty-three patients (24.7%) had grossly clear dialysate which was not sent for laboratory analysis. None of these patients required laparotomy. We conclude that the WBC count in DPL fluid is of no diagnostic value in victims of blunt abdominal trauma who are lavaged within 4 hours of injury. In addition, laboratory analysis of clear dialysate is not required in these patients.  相似文献   
942.
Gonadoblastoma, a rare gonadal neoplasm, presents most frequently in phenotypic female or phenotypically male patients with dysgenetic gonads or undescended testes. To date, only 2 cases of gonadoblastoma have been reported in anatomically normal male patients with scrotal testes. Both of these patients presented with testicular masses and germ cell tumors. We report a case of a genotypically and phenotypically normal, fertile man with descended testes who on evaluation for chronic orchialgia had a gonadoblastoma unaccompanied by a germ cell neoplasm. The tumor was nonpalpable and was initially discovered on scrotal ultrasound.  相似文献   
943.
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   
944.
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   
945.
946.
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   
947.
Summary Previous studies of Alcian blue-induced birefringence in adult avian cortical bone showed that a short period of intermittent loading rapidly produces an increased level of orientation of proteoglycans within the bone tissue. In the absence of further loading, this persists for over 24 hours. We have proposed that this phenomenon could provide a means for “capturing” the effects of transient strains, and so provide a persistent, constantly updated strain-related influence on osteocyte populations related to the bones' averaged recent strain history, in effect, a “strain memory” in bone tissue. In our present study, we use the Alcian blue-induced birefringence technique to demonstrate that proteoglycan orientation also occurs after intermittent loading of both cortical and cancellous mammalian bonein vivo andin vitro. We also show that the change in birefringence is proportional to the magnitude of the applied strain, and that the reorientation occurs rapidly, reaching a maximal value after only 50 loading cycles. Examination of electron micrographs of bone tissue after staining with cupromeronic blue allows direct visualization and quantification of the change in proteoglycan orientation produced by loading. This shows that intermittent loading is associated with a realignment of the proteoglycan protein cores, bringing them some 5 degrees closer to the direction of collagen fibrils in the bone matrix.  相似文献   
948.
Immediate reconstruction of more than 1000 breasts was performed on high-risk patients on whom a prophylactic mastectomy was done. The mastectomy removes as much breast tissue as possible while leaving sufficient skin, and possibly the nipple-areola complex, to enable immediate reconstruction. The creation of symmetrical, well-balanced muscle pockets for the implant is the most important factor in producing satisfactory results in these cases.  相似文献   
949.
Bladder mucosa in urethral reconstructions   总被引:6,自引:0,他引:6  
  相似文献   
950.
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