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   1601篇
  免费   98篇
  国内免费   9篇
耳鼻咽喉   14篇
儿科学   72篇
妇产科学   17篇
基础医学   134篇
口腔科学   47篇
临床医学   220篇
内科学   289篇
皮肤病学   18篇
神经病学   67篇
特种医学   114篇
外科学   220篇
综合类   46篇
预防医学   268篇
眼科学   10篇
药学   117篇
中国医学   2篇
肿瘤学   53篇
  2021年   33篇
  2020年   16篇
  2019年   12篇
  2018年   18篇
  2016年   28篇
  2015年   27篇
  2014年   37篇
  2013年   57篇
  2012年   63篇
  2011年   50篇
  2010年   46篇
  2009年   49篇
  2008年   50篇
  2007年   55篇
  2006年   63篇
  2005年   50篇
  2004年   55篇
  2003年   54篇
  2002年   51篇
  2001年   35篇
  2000年   30篇
  1999年   37篇
  1998年   49篇
  1997年   39篇
  1996年   27篇
  1995年   22篇
  1994年   35篇
  1993年   30篇
  1992年   36篇
  1991年   30篇
  1990年   37篇
  1989年   43篇
  1988年   33篇
  1987年   22篇
  1986年   29篇
  1985年   20篇
  1984年   20篇
  1983年   28篇
  1982年   18篇
  1981年   17篇
  1980年   20篇
  1979年   17篇
  1978年   16篇
  1977年   12篇
  1976年   12篇
  1974年   11篇
  1973年   11篇
  1930年   12篇
  1927年   10篇
  1926年   11篇
排序方式: 共有1708条查询结果,搜索用时 15 毫秒
1.
2.
OBJECTIVE: Nocturnal enuresis is a common pediatric problem, the etiology of which is unclear. In recent years, various studies have been published stating that children with nocturnal enuresis exhibit growth and skeletal maturation retardation. METHODS: In this cross-sectional study, we included 27 patients (16 boys, 11 girls) between the ages of 6 and 14 years who had presented with primary nocturnal enuresis (PNE) complaints. We included in the evaluation 19 healthy subjects (12 boys, 7 girls), who were the siblings of the children with PNE, as the control group. RESULTS: The patients in both groups were similar in chronological age, bone age, height and weight, with no significant difference between groups (P>0.05). CONCLUSION: The two groups in our study consisted of the same genetic background. Thus, our results were found to be different from the previous studies. We have concluded that there is no direct relationship between enuresis nocturnal and skeletal maturation.  相似文献   
3.
Incidence of hypertension in the Framingham Study.   总被引:6,自引:1,他引:5       下载免费PDF全文
Incidence and trends in incidence of definite hypertension were analyzed based on 30 years follow-up of 5,209 subjects in the Framingham Heart Study cohort. Based on pooling of 15 two-year periods, hypertension incidence per biennium increased with age in men from 3.3 per cent at ages 30-39 to 6.2 per cent at ages 70-79, and in women from 1.5 per cent at ages 30-39 to 8.6 per cent at ages 70-79. No consistent trend in incidence rates was evident for either sex from the 1950s through the 1970s. The proportion of hypertensive subjects receiving antihypertensive medication has increased since 1954-58 and exceeded 80 per cent for both men and women ages 60-89 years in 1979-81. Incidence data presented in this report may serve as a baseline for assessing the impact of future public health efforts in the primary prevention of hypertension.  相似文献   
4.
5.
R W Evans  D L Manninen  L P Garrison  A M Maier 《JAMA》1986,255(14):1892-1898
Heart transplantation has now achieved a therapeutic status similar to that of cadaveric renal transplantation. Depending on patient selection criteria, it is estimated that as many as 15,000 people per year could conceivably benefit from a heart transplant, but the actual number of persons who will benefit is severely constrained by donor supply. Availability of heart donors was estimated based on data obtained on 1,955 organ donors in the United States. The results show that because of age and other contraindications, only 400 to 1,100 viable donor hearts may be available each year. Donor supply is the most critical determinant of the future of heart transplantation since it will dictate the number of transplants performed, the survival of transplant recipients, the total program expenditures associated with heart transplantation, the nature of the legal and ethical issues involved, the number of cardiac transplant programs required to make optimal use of the available donor hearts, and the future role of mechanical circulatory support systems.  相似文献   
6.
Operative cholangiography   总被引:3,自引:0,他引:3  
The value of operative cholangiography in the management of biliary tract disease has been questioned. To better define the role of cholangiography, we reviewed 579 consecutive cholecystectomies done by 1 group of surgeons in a small rural practice over 8 years. Cholangiography demonstrated unsuspected common bile duct disease in 5% of the procedures, while 12% of the patients were spared an unnecessary choledochotomy after a normal cholangiogram was obtained. There was no morbidity, mortality, or prolongation of the hospital stay attributed to the cholangiographic procedure. These findings bolster the argument for routine cholangiography as a safe, effective, and helpful screening examination for patients who are at risk for having common bile duct disease.  相似文献   
7.
8.
9.
Single-positive thymocytes are the immediate precursors of peripheral recent thymic emigrants (RTE) which develop into mature peripheral T cells. The functional ability of RTE is unclear but their state of differentiation may be relevant to the development of tolerance to peripheral “self” antigens. Since RTE are difficult to analyze, precursor CD4+/8 thymocytes were assessed in a model in vivo to determine their functional capability and their susceptibility to tolerance induction. The ability of both heat-stable antigen-positive (HSA+) (immature) and HSA (mature) single-positive thymocytes to cause graft-versus-host disease (GVHD) across non-major histocompatibility complex differences was examined. Both HSA and HSA+ CD4+/8 thymocytes from C3H mice caused lethal GVHD in AKR recipients as did CD4+ peripheral T cells in controls. Further, neonatal C3H thymocytes also caused lethal GVHD in AKR recipients. Since CD4+/8 thymocytes are the precursors of RTE, these results suggest that RTE are not susceptible to tolerance induction to “minor” antigens and may have a normal immune function in vivo. This would suggest that peripheral tolerance may be dependent upon the manner of antigen presentation rather than T cell maturity.  相似文献   
10.
High serum fluoride (F-) in patients with chronic renal failure (CRF) and end-stage renal disease (ESRD) is associated with risk of renal osteodystrophy and other bone changes. This study was done to determine F- in normal healthy controls and patients with ESRD on haemodialysis (HD) or peritoneal dialysis (PD). Seventeen healthy controls (12 males, 5 females) and 39 ESRD patients on dialysis (17 males, 22 females) were recruited in the study in a community with 47.4 +/- 3.28 microM/l (range 44-51 microM/l) of F- content in drinking water. Control subjects showed a mean serum F- concentration of 1.08 +/- 0.350 microM/l. Males in control group showed slightly higher F- levels (1.15 +/- 0.334, range 0.55-1.9 microM/l) than females (0.92 +/- 0.370, range 0.6-1.5 microM/l). Mean serum F- concentration did not correlate significantly with age and sex among control subjects, whereas such correlation was observed in patients with ESRD on dialysis. Mean serum F- concentration was significantly higher in patients on dialysis (2.67 +/- 1.09, range 0.8-5.2 microM/l) than normal controls. When grouped according to sex, the mean serum F- concentration in males (3.05 +/- 1.04, range 1.8-5.2 microM/l) was significantly higher than females (2.38 +/- 1.08, range 0.8-5.2 microM/l). When patients were grouped according to age, it was observed that F- concentration was significantly higher in patients with age groups 21-70 (2.86 +/- 1.05) than those with age group 13-20 years (1.42 +/- 0.531). Thus F- concentration correlated with age and sex, being higher in males and above 20 years. Despite appreciable clearance of F- (39-90%) across the peritoneum, patients on CAPD showed higher serum F- concentration than those on HD (3.1 +/- 1.97 vs 2.5 +/- 1.137 microM/l). Of the total 39 patients on dialysis 39% had their serum F- concentration above 3.0 microM/l, posing the risk of renal osteodystrophy.   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