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   1096291篇
  免费   72931篇
  国内免费   1419篇
耳鼻咽喉   15387篇
儿科学   35529篇
妇产科学   29330篇
基础医学   156962篇
口腔科学   30076篇
临床医学   96718篇
内科学   207872篇
皮肤病学   24829篇
神经病学   83598篇
特种医学   43765篇
外国民族医学   214篇
外科学   166118篇
综合类   21796篇
现状与发展   1篇
一般理论   266篇
预防医学   75795篇
眼科学   24901篇
药学   87159篇
  7篇
中国医学   2822篇
肿瘤学   67496篇
  2019年   8038篇
  2018年   11653篇
  2017年   9201篇
  2016年   10498篇
  2015年   11678篇
  2014年   15798篇
  2013年   22922篇
  2012年   31560篇
  2011年   33378篇
  2010年   19477篇
  2009年   18388篇
  2008年   30900篇
  2007年   33094篇
  2006年   33674篇
  2005年   32014篇
  2004年   30537篇
  2003年   29363篇
  2002年   28263篇
  2001年   60679篇
  2000年   62182篇
  1999年   51507篇
  1998年   12722篇
  1997年   11218篇
  1996年   11187篇
  1995年   10476篇
  1994年   9486篇
  1993年   9000篇
  1992年   38126篇
  1991年   36640篇
  1990年   36115篇
  1989年   34590篇
  1988年   31147篇
  1987年   30298篇
  1986年   28523篇
  1985年   26734篇
  1984年   19395篇
  1983年   16273篇
  1982年   8927篇
  1979年   17227篇
  1978年   11559篇
  1977年   10362篇
  1976年   8970篇
  1975年   10193篇
  1974年   11818篇
  1973年   11410篇
  1972年   10877篇
  1971年   10192篇
  1970年   9358篇
  1969年   9033篇
  1968年   7999篇
排序方式: 共有10000条查询结果,搜索用时 18 毫秒
991.
Retrospectively we analyzed the histocompatibility data and clinical results of bone marrow transplantation in 51 patients who received marrow from unrelated donors (UD) from 1977 to 1987 at one of four UK BMT centers. We compared the results with those obtained in 51 transplants carried out at the same centers using HLA-identical (ID) sibling donors. Of the UD/recipient pairs 32 (63%) were serologically identical for HLA A, B, and DR antigens, and 37% showed varying degrees of mismatch. UD-BMT primary diagnoses were: severe aplastic anemia or Fanconi's anemia (n = 17), acute leukemia (n = 11), chronic myeloid leukemia (n = 21), and other conditions (n = 2). T cell depletion of the graft was associated with a significant improvement in survival in both UD and ID-BMT. Graft failure was more common in recipients of UD than of ID transplants (13 [25%] vs. 5 [10%] P = 0.05) but there was no significant difference in the frequency of acute or chronic graft-versus-host disease. Actuarial survival was superior for recipients of ID transplants (UD vs. ID: 49% vs. 78%, respectively, at 3 months; 32% vs. 63% at one year). Reduced survival for recipients of UD-BMT was confirmed in case control regression analysis (relative risk 3.0, P = 0.01). Nevertheless in patients whose only alternative is a partially mismatched family donor we think that UD-BMT is justified.  相似文献   
992.
Acute CyA nephrotoxicity involves alteration in the proximal tubule and leads to glomerular lesions. Administration of a vasodilatator agent such as the prostaglandin E1 analogue Rioprostil (Bayer AG, BAY 06893) might prevent preglomerular vasoconstriction and hence reduce cyclosporin nephrotoxicity. As an increased excretion of urinary enzymes as a consequence of CyA-nephrotoxicity is well known we investigated in 40 male Wistar rats the excretion of three urinary enzymes: the brush border enzyme gamma-glutamyltransferase (GGT), the leucine aminopeptidase (LAP), and the lysosomal enzyme N-acetyl-beta-glucosaminidase (NAG). Additionally we determined s-creatinine and CyA plasma level. The kidneys were studied histologically at the end of the study. Wistar rats receiving 20 or 50 mg CyA/kg/d showed a marked deterioration in renal function and an increase of all urinary enzymes determined. In the rats receiving 20 mg CyA/kg/d and Rioprostil (150 micrograms/d) renal function and the enzymes determined remained in the normal range. There was no change in the enzyme excretion and only a minor improvement of renal function in rats receiving 50 mg CyA/kg/d and Rioprostil. Histological findings showed prevention of CyA nephrotoxicity in the 20 mg/kg/d group and diminished renal damage in the 50 mg/kg/d group.  相似文献   
993.
994.
995.
The concentration of brain type creatine kinase (CK-BB) was measured in blood from the internal jugular vein in 32 children (less than 1 year old) with congenital heart disease. In transposition of the great arteries the CK-BB levels were significantly higher than in children without cyanosis (10.1 +/- 4.1 vs. 3.0 +/- 0.5 ng/ml). A negative correlation was found for CK-BB concentration and arterial oxygen saturation (r = -0.41, p less than 0.02 for all children and r = -0.62, p less than 0.05 for those with tetralogy of Fallot). It is suggested that the increased CK-BB levels in the blood of cyanotic children reflect chronic cerebral hypoxia, which may explain other reports of reduced psycho-intellectual function in patients with cyanotic heart disease.  相似文献   
996.
997.
998.
This is a case report on a patient with double cancer of kidney and urinary bladder. The patient was a 65-year-old female, and she was admitted with the chief complaint of gross hematuria and right flank pain. After careful examinations, she was diagnosed with right nonfunctioning kidney caused by invasive bladder cancer. Computerized tomography incidentally revealed a mass in the upper pole of the left kidney. Selective left renal arteriography showed stretched arteries and irregularity and tortuosity of the smaller vessels. She was diagnosed with double cancer of bladder and left kidney. Owing to the damage of the right renal function, left partial nephrectomy, total cystectomy, right nephroureterectomy and left ureterocutaneostomy were performed. According to DMSA scintigraphy measured 15 days later, the uptake value of the left kidney was 13.25%, compared to the preoperative value of 25.62%. To date, this case is 36th reported case in Japan.  相似文献   
999.
Proximal displacement of the femoral head can been seen sometimes after Chiari pelvic osteotomy. In order to clarify the causes of the displacement, a quantification analysis was performed to evaluate the factors of this osteotomy. The statistical analysis showed that 54% of the causes could be explained as being due to the angle of osteotomy, obesity ratio, the variation of the acetabular trochanteric distance, and other three factors. Paying attention to get good results: 1) making the angle of osteotomy from 11 degrees to 20 degrees, 2) keeping the variation of the acetabular trochanteric distance within 20mm, 3) the improvement of the lever arm ratio within 15%, and 4) the approximate acetabular index above 30%. In a case with the greater trochanter pulled down, a computer simulation showed that the centripetal force of the femoral head was decreased, and the displacement was increased.  相似文献   
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