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   1557篇
  免费   98篇
  国内免费   26篇
儿科学   146篇
妇产科学   17篇
基础医学   166篇
口腔科学   66篇
临床医学   156篇
内科学   358篇
皮肤病学   38篇
神经病学   30篇
特种医学   328篇
外科学   90篇
综合类   21篇
预防医学   62篇
眼科学   16篇
药学   92篇
  1篇
中国医学   1篇
肿瘤学   93篇
  2023年   3篇
  2022年   5篇
  2021年   18篇
  2020年   8篇
  2019年   14篇
  2018年   24篇
  2017年   19篇
  2016年   23篇
  2015年   33篇
  2014年   33篇
  2013年   51篇
  2012年   20篇
  2011年   19篇
  2010年   44篇
  2009年   84篇
  2008年   23篇
  2007年   45篇
  2006年   41篇
  2005年   36篇
  2004年   23篇
  2003年   28篇
  2002年   24篇
  2001年   20篇
  2000年   22篇
  1999年   32篇
  1998年   101篇
  1997年   118篇
  1996年   112篇
  1995年   77篇
  1994年   85篇
  1993年   99篇
  1992年   19篇
  1991年   18篇
  1990年   19篇
  1989年   45篇
  1988年   39篇
  1987年   26篇
  1986年   32篇
  1985年   31篇
  1984年   17篇
  1983年   15篇
  1982年   19篇
  1981年   34篇
  1980年   20篇
  1979年   8篇
  1978年   8篇
  1977年   21篇
  1976年   19篇
  1975年   6篇
  1970年   1篇
排序方式: 共有1681条查询结果,搜索用时 15 毫秒
91.
A patient with progressive osteolysis of the carpal and tarsal bones with glomerulonephritis of unusual severity is described. There was a notable absence of osteodystrophy in this and other reported cases who had chronic renal failure.  相似文献   
92.
Pneumocystis carinii pneumonia studied by gallium-67 scanning   总被引:1,自引:0,他引:1  
The validity and reliability of gallium-67 (Ga-67) scanning for diagnosis and follow-up of Pneumocystis carinii pneumonia (PCP) were assessed in 34 patients thought to have pulmonary complications of acquired immunodeficiency syndrome (AIDS). Overall sensitivity was 94% and specificity 74%. Among patients with normal or equivocal chest radiographs at the time of admission, sensitivity was 86% and specificity 85%. The authors consider Ga-67 scanning a valid and reliable adjunct in the diagnosis of PCP in AIDS patients with respiratory symptoms when the chest radiograph is normal or equivocal.  相似文献   
93.
Urinary tract infection in infants and children evaluated by ultrasound   总被引:1,自引:0,他引:1  
Kangarloo  H; Gold  RH; Fine  RN; Diament  MJ; Boechat  MI 《Radiology》1985,154(2):367-373
Fifty-nine pediatric patients with urinary tract infection (UTI) underwent renal ultrasonography, excretory urography, and voiding cystourethrography. The imaging procedures were analyzed retrospectively to determine their relative effectiveness in detecting abnormalities that might predispose the patient to UTI. Voiding cystourethrography provided valuable information, particularly the presence or absence of vesicoureteral reflux, that could not be obtained from the other procedures. Excretory urography was less specific than ultrasonography in the majority of patients, with the exception of those who had renal scarring. The authors recommended ultrasonography as the initial imaging procedure in the evaluation of children with UTI. When the sonogram is normal, excretory urography is not considered necessary, but voiding cystourethrography is thought to be essential. If sonography is abnormal, excretory urography and/or other follow-up studies are indicated.  相似文献   
94.
Serological data indicate that hepatitis C virus (HCV) infection is very common among chronic hemodialysis (HD) patients. Circumstantial evidence suggests that hemodialysis per se is an important risk factor for this infection. We used a novel methodology, the branched DNA (bDNA) signal amplification assay, which is capable of detecting HCV RNA and of quantifying HCV viral load in serum, to prospectively determine the rate of acquisition of HCV infection in 274 anti-HCV-negative patients undergoing HD treatment in four hemodialysis units. Moreover, we used bDNA testing to analyze the dynamics of HCV acquisition among HD patients, a high-risk group for HCV infection with immune compromise conferred from uremia. Two patients were identified with de novo acquisition during 1 year of prospective bDNA testing. Thus, the HCV incidence was 0.73% per year. De novo acquisition of HCV infection was observed in the absence of identifiable parenteral risk factors. Both patients showed the same pattern of HCV acquisition: they underwent an initial viremic phase that was associated with an increase in alanine transaminase (ALT) activity and that preceded the anti-HCV seroconversion. This was followed by HCV RNA clearance and normalization of ALT activity. Anti-HCV positivity occurred 1 and 2 months after the ALT increase in the first and second patients, respectively. Although HCV incidence was low (0.73%), further research is warranted to set the optimal policy for eliminating the risk of nosocomial transmission of HCV in the HD setting. Our findings show the pattern of HCV acquisition in chronic HD patients and emphasize the need to screen the HD population for ALT measurement combined with anti-HCV testing for detecting hepatitis C. HCV RNA testing can identify HCV before seroconversion in individuals with deranged liver function tests. The acquisition of HCV in HD patients without identifiable risk is confirmed.  相似文献   
95.
96.
97.
98.
99.
Aim: This study investigates the effect of rapid weight gain in term children, adolescents and young adults born appropriate for gestational age. Methods: In all, 173 girls and 178 boys aged 6.1–19.9 (12.5 ± 3.1)years participated. Rapid weight gain (group 1) was defined as a change in weight‐SDS (standard deviation score) from birth till two years >0.67, ‘no change’ as ≥?0.67 and ≤0.67 (group 2) vs ‘slow weight gain’ as 90th age‐/sex‐specific BMI‐percentile was defined as overweight. Parental BMI, socio‐economic status and lifestyle were assessed as confounders. Results: A total of 22.8% gained weight rapidly, and 15.7% was overweight. Group 1 compared with group 2 and 3 subjects was taller, heavier and had a higher prevalence of overweight (girls/boys: 26.2%/28.9% vs 11.6%/19.0% vs 2.8%/5.0%; p < 0.01/p < 0.05). Concomitantly, a higher WC, %FM and FFM were observed. Rapid weight gain was positively associated with REE (adjusted for FFM) in boys (r = 0.26; p < 0.01), but not with cardio‐metabolic risk factors. Conclusion: Rapid weight gain was related to increases in height, weight, a higher prevalence of overweight and central fat distribution. In addition, rapid weight gain was related to a higher REE in boys, but not to cardio‐metabolic risk factors.  相似文献   
100.
血清骨唾液酸蛋白的生物变异性研究   总被引:3,自引:0,他引:3       下载免费PDF全文
目的 骨唾液酸蛋白(Bone sialoprotein,简称BSP)是由成骨细胞分泌的一种非胶原蛋白质,反映骨转换和骨形成的指标。最近研究认为:血清BSP浓度可反映破骨细胞活性和骨吸收过程,也可能是一个骨吸收指标。本实验测定了血清BSP在人体内的生物变异性。方法 采用RIA 法测定了290例不同性别和年龄的正常人血清BSP的正常值,血清BSP的天-天变异性及24 h 生物周期。 结果 在儿童组血清BSP正常水平明显高于成人组,其最高值在新生儿期和青春期。绝经后妇女其血清浓度比绝经前妇女水平明显升高(P< 0.05)。血清BSP在每天同一时间的波动范围在 7.3% 至17.7% (平均11.7% )。24 h 内有一个明显的生物周期性变化,表现为峰值在凌晨4~8 时,然后逐渐下降直到午后14时为最低。其生物周期的最大波幅为±20% ,(平均血浓度为10.5 ng/m l)。结论 血清BSP反映了骨转换的生理变化与年龄有明显相关性,其血清水平24 h 内有一个明显的生物周期,而天与天之间变异性较小。  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