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   11047篇
  免费   518篇
  国内免费   29篇
耳鼻咽喉   147篇
儿科学   165篇
妇产科学   150篇
基础医学   1547篇
口腔科学   332篇
临床医学   711篇
内科学   2386篇
皮肤病学   116篇
神经病学   716篇
特种医学   963篇
外科学   1711篇
综合类   62篇
预防医学   280篇
眼科学   130篇
药学   905篇
中国医学   19篇
肿瘤学   1254篇
  2022年   79篇
  2021年   153篇
  2020年   76篇
  2019年   116篇
  2018年   160篇
  2017年   117篇
  2016年   154篇
  2015年   162篇
  2014年   192篇
  2013年   260篇
  2012年   368篇
  2011年   464篇
  2010年   266篇
  2009年   256篇
  2008年   425篇
  2007年   452篇
  2006年   465篇
  2005年   495篇
  2004年   496篇
  2003年   483篇
  2002年   457篇
  2001年   459篇
  2000年   472篇
  1999年   434篇
  1998年   156篇
  1997年   119篇
  1996年   128篇
  1995年   91篇
  1994年   83篇
  1993年   68篇
  1992年   335篇
  1991年   288篇
  1990年   305篇
  1989年   329篇
  1988年   286篇
  1987年   289篇
  1986年   243篇
  1985年   243篇
  1984年   156篇
  1983年   104篇
  1982年   55篇
  1981年   48篇
  1979年   76篇
  1978年   69篇
  1977年   65篇
  1976年   44篇
  1974年   59篇
  1972年   55篇
  1970年   49篇
  1968年   44篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
Malignant phyllodes tumour with a noninvasive ductal carcinoma component   总被引:2,自引:0,他引:2  
 A malignant phyllodes tumour with a noninvasive ductal carcinoma component is reported. The patient was an 80-year-old Japanese woman with a breast tumour detected by routine physical examination. A simple mastectomy was performed. The excised tumour was 10.5×9.4×5.4 cm in size and bulged into the skin with ulceration. The macroscopic appearance was that of a phyllodes tumour. Histologically the tumour consisted mainly of stromal components with a leaf-like structure lined by atypical ductal epithelium. The epithelial component showed gradual evolution to intraductal papillary carcinoma in a few areas. The stromal component was composed mainly of fibrosarcoma with areas of osteosarcoma and rhabdomyosarcoma. Neither stromal invasion of intraductal carcinoma nor transition between the stromal and epithelial elements was seen. Three months after the operation, death occurred, with multiple pulmonary and subcutaneous metastases. This case probably represents malignant change in both the stromal and the epithelial components of a phyllodes tumour. Since the two elements were independent, the possibility that a phyllodes tumour may be one of the origins of true carcinosarcoma is raised. Received: 11 March 1997 / Accepted: 5 May 1997  相似文献   
82.
We determined the long-term prognosis for patients with mitral-valve prolapse documented by echocardiography by following 237 minimally symptomatic or asymptomatic patients for a mean of 6.2 years (range, 1 to 10.4). The actuarial eight-year probability of survival was 88 per cent, which is not significantly different from that for a matched control population. An initial left ventricular diastolic dimension exceeding 60 mm was the best echocardiographic predictor of the subsequent need for mitral-valve replacement (17 patients). Of the 97 patients with redundant mitral-valve leaflets identified echocardiographically, 10 (10.3 per cent) had sudden death, infective endocarditis, or a cerebral embolic event; in contrast, of the 140 patients with nonredundant valves, only 1 (0.7 per cent) had such complications (P less than 0.001). Most patients with echocardiographic evidence of mitral-valve prolapse have a benign course, but subsets at high risk for the development of progressive mitral regurgitation, sudden death, cerebral embolic events, or infective endocarditis can be identified by echocardiography.  相似文献   
83.
Association between HLA and Japanese patients with rheumatoid arthritis   总被引:12,自引:0,他引:12  
Japanese patients with rheumatoid arthritis (RA) were observed to have a statistical association with HLA-DR4, MT3. Strong association between the clinical severity of RA and HLA was also observed. Male patients had a stronger association with HLA than female patients. Males are more resistant to RA than females. This suggested that the threshold of liability for RA is higher in males than in females. Japanese patients with RA with systemic vasculitis were negative for HLA-Bw44 and had antilymphocytotoxic autoantibody, indicating that RA with systemic vasculitis is different in etiology from RA without systemic vasculitis.  相似文献   
84.
Dendritic cells (DC) are professional antigen-presenting cells in the immune system. Gene transduction of DC with tumor-associated antigen (TAA) or other genes that enhance the immune reaction has been considered theoretically useful for DC-based immunotherapy. However, gene transduction of DC generated from human peripheral blood monocytes has been difficult due to its low efficiency, even when adenoviral vector was used at high multiplicity of infection (MOI). In the present study, we examined the effect of centrifugal force to enhance efficiency of adenovirus-mediated gene transduction into human monocyte-derived DC at various rotor speeds at various temperatures for various times. We judged the transduction efficiency using enhanced green fluorescence protein (EGFP)-expressing adenoviral vector, and the best condition for centrifugal transduction was determined as 2000 x g at 37 degrees C for 2 h at an MOI of 10 or greater. At an MOI of 50 without centrifugation, the gene transduction efficiency was about 66% and mean fluorescence intensity (MFI) of EGFP expression was about 150 (at 37 degrees C for 2 h). With centrifugal transduction (2000 x g at an MOI of 50 at 37 degrees C for 2 h), 86% or more DC were gene-modified, and especially, MFI of EGFP expression was highly enhanced (MFI: about 3100 or greater). Centrifugally gene-transduced DC were not damaged and were thoroughly functional as measured by mixed lymphocyte reaction (MLR). The centrifugal method was also applicable to human monocytes and K562 cells. The centrifugal transduction method with adenoviral vector might be helpful for the generation of gene-modified DC.  相似文献   
85.
The presence of a significant organ dysfunction does not immediately exclude patients from consideration for treatment with a left ventricular assist system (LVAS). However, in treating morbid circulatory shock patients with multiple organ failure, it is important to know the preoperative and postoperative factor or factors related to the recovery of the damaged organ function. In this study, we retrospectively analyzed patients receiving a LVAS at our institution and tried to determine the important factors related to the survival of patients with multisystem failure. Twenty-seven patients who underwent LVAS placement at Saitama Medical School Hospital between 1993 and 2003 were included in this study. The preoperative risk factors analyzed were renal dysfunction, respiratory dysfunction, hepatic dysfunction, the existence of active infection, and the combination of all four factors. As a postoperative factor, the pump flow index (mean LVAS pump flow during the first 2 weeks after LVAS surgery divided by the body surface area) was analyzed. None of the analyzed preoperative factors could predict survival after LVAS surgery, but a pump flow index of less than 2.5 l/min/m2 had a significant relationship with death after LVAS surgery. Further analysis revealed that all the patients with a pump flow index of 3.0 l/min/m2 or more could overcome preoperative organ dysfunction. Congestive heart failure patients with multisystem failure need luxury pump flow for successful LVAS surgery; this factor could be especially important in device selection and postoperative management.  相似文献   
86.
The secretion of tumor necrosis factor (TNF)-α from macrophages is regulated by both priming and triggering signals. We found that macrophages from mice lacking γδ T cells [T cell receptor (TCR) δ?/- mice], which lack the gene encoding the δ chain, produced only small amounts of TNF-α in response to lipopolysaccharide (LPS) and showed a reduced level of expression of CD14. Pre-incubation of macrophages from TCR δ-/- mice with γδ T cells from their TCR δ+/- littermates restored their capacity to produce TNF-α in response to LPS. The priming activity of γδ T cells was in part inhibited by neutralizing anti-interferon (IFN)-γ monoclonal antibodies. Collectively, these results suggest that γδ T cells play a role in priming macrophages to a steady state of activation via IFN-γ secretion, which allows them to produce TNF-α when exposed to LPS.  相似文献   
87.
A 65-year-old man was admitted for dysuria. He had been irradiated 60Co for malignant lymphoma of tonsils 2 years earlier. The findings of palpation of prostate, retrograde urethrogram and urethroscopy strongly suggested benign prostatic hypertrophy. Retropubic prostatectomy was performed and 18 g of "adenoma" was resected. By histological observation, the "adenoma" proved to be malignant lymphoma. This tumor belonged to follicular lymphoma, medium-sized cell type of LSG non-Hodgkin's lymphoma classification. After the operation, he left our hospital for a personal reason and received systemic chemotherapy at another hospital.  相似文献   
88.
Here, we report 2 cases of epididymovasostomy operation in which good results were obtained. These operations were done for patients whose complaints were male sterility due to obstructive azospermia after bilateral epididymitis. The method of this operation was reported by Silber in 1978 as "specific tubule technique", and excellent results have been reported. Herein, we introduce this technique perhaps for the first time in Japan, and the characteristics of this method are considered. The important factors and characteristics of this method are that it is very reasonable with a high success rate, it is more difficult than microsurgical vasovasostomy, it is a time-consuming operation. Epididymovasography should not be done preoperatively but intraoperatively, if possible and chronic epididymitis should be ruled out by serological study and culture study.  相似文献   
89.
Neurosurgical Review - The present study aimed to determine the incidence of intraprocedural motor-evoked potential (MEP) changes and to correlate them with intraprocedural ischemic complications...  相似文献   
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