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   13767篇
  免费   668篇
  国内免费   164篇
耳鼻咽喉   125篇
儿科学   296篇
妇产科学   257篇
基础医学   1612篇
口腔科学   310篇
临床医学   1140篇
内科学   3827篇
皮肤病学   248篇
神经病学   1473篇
特种医学   444篇
外科学   1963篇
综合类   50篇
预防医学   645篇
眼科学   139篇
药学   823篇
中国医学   68篇
肿瘤学   1179篇
  2023年   96篇
  2022年   165篇
  2021年   413篇
  2020年   243篇
  2019年   300篇
  2018年   420篇
  2017年   267篇
  2016年   349篇
  2015年   428篇
  2014年   522篇
  2013年   782篇
  2012年   1127篇
  2011年   1038篇
  2010年   643篇
  2009年   577篇
  2008年   947篇
  2007年   950篇
  2006年   836篇
  2005年   900篇
  2004年   779篇
  2003年   664篇
  2002年   636篇
  2001年   113篇
  2000年   103篇
  1999年   85篇
  1998年   122篇
  1997年   105篇
  1996年   73篇
  1995年   75篇
  1994年   63篇
  1993年   54篇
  1992年   57篇
  1991年   62篇
  1990年   43篇
  1989年   42篇
  1988年   55篇
  1987年   44篇
  1986年   38篇
  1985年   44篇
  1984年   32篇
  1983年   28篇
  1982年   28篇
  1981年   28篇
  1980年   46篇
  1979年   18篇
  1978年   13篇
  1977年   16篇
  1976年   16篇
  1975年   14篇
  1974年   13篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
991.
We report here the genetic findings of a new isolated familial somatotropinoma (IFS) kindred in which the mother (subject I:2) and one daughter (subject II:2) are affected; their ages at diagnosis were 25 and 14 years respectively. Additionally, patient I:2 developed virilization due to an androgen-secreting adrenocortical mass, presenting clinical and molecular features of sporadic adrenal carcinoma. To genotype this family and to narrow down the candidate interval of the putative IFS gene at 11q13, we performed haplotyping on the DNA from all five members of the family and allelotyping of one available somatotropinoma using polymorphic microsatellite markers from chromosome region 11q12.1-11q13.5. Results indicated that the disease haplotype, between markers D11S956 and D11S527, was transmitted from subject I:2 only to subject II:2. A meiotic recombination event was detected in the fraternal twin sister of II:2 (subject II:1), but her disease status is unknown. Since she is only 18 years old this genetic event cannot yet narrow down the area involved in the pathogenesis of IFS. Allelotyping of the somatotropinoma from II:2 revealed loss of the chromosome carrying the wild-type copy of the putative IFS gene inherited from her father. These results support the involvement of a tumor suppressor gene at 11q13.1-q13.3 in the pathogenesis of IFS.  相似文献   
992.
993.
994.
995.
996.
BACKGROUND AND AIMS: The combination of high prevalence of inactivity in the older population, and high risk of ill-health and disability associated with inactivity, suggests that interventions that are successful in increasing levels of activity may have a great impact on population health in later life. With advancing age, the risk of developing serious nutritional deficiencies also increases. This study was designed to assess the effects of dietary amino acid supplementation on effort tolerance in healthy elderly subjects with reduced physical activity. METHODS: Forty-four subjects (age > 65 years) with sedentary life-style and lower health-related quality of life were studied. Subjects, in an open-label fashion, received an oral amino acid mixture (AAM, 12 g/day) containing essential and non-essential amino acids for a 3-month period. Ambulatory dysfunction resulting in sedentary life-style was assessed by a 6-min walk test. A walking impairment questionnaire (WIQ) was used to evaluate self-perceived ambulatory dysfunction. Maximal isometric muscular strength of the right hand was measured during isometric exercise by a handgrip dynamometer. RESULTS: The 6-min walk distance increased from 214.5 +/- 32 to 262.8 +/- 34.8 m (p < 0.001) after AAM treatment. The baseline scores on the three subscales of WIQ changed significantly during treatment: WIQ distance increased from 56.2 +/- 12.9 to 66.3 +/- 12.8% (p < 0.001); WIQ speed from 52 +/- 12.6 to 69.2 +/- 14.8% (p < 0.001) and WIQ stairs from 74.4 +/- 22.6 to 94.2 +/- 25% (p < 0.001), as did maximal isometric muscular strength (16.6 +/- 2.4 vs 19.2 +/- 2.2 kg, p < 0.001). Changes in plasma glucose (+11 +/- 11 mg/dL), total cholesterol (0 +/- 39 mg/dL), HDL cholesterol (0 +/- 17 mg/dL), and triglycerides (-11 +/- 58 mg/dL) were not significant between baseline and AAM. CONCLUSIONS: An oral amino acid supplement, as used in this pilot study, improves ambulatory capacity and maximal isometric muscle strength in elderly subjects without affecting the main metabolic parameters. Amino acid supplementation may thus represent useful non-pharmacological intervention to maintain physical fitness in these subjects.  相似文献   
997.
In the past decade, different modalities of antiviral therapy have been adopted aimed at eradicating hepatitis C virus infection. Initially, interferon was used in monotherapy, then interferon combined with ribavirin and amantadine. Recently, interferon has been conjugated with polyethylene glycol to allow optimization of its pharmacokinetic properties and to improve its antiviral activity. This study focused on the characteristics of the skin reactions that we observed in 27 patients with na?ve hepatitis C who received polyethylene glycol interferon-ribavirin-amantadine or polyethylene glycol interferon-ribavirin and in 10 previous non-responders to interferon monotherapy who were retreated with triple therapy. In 9 patients (7 on triple therapy) dermatitis-like lesions were observed, and in 5 the severity of the lesions necessitated withdrawal from therapy.  相似文献   
998.
999.
1000.
We developed a summary score of data obtained from nerve conduction studies (NCS). The principle of such approach is that when a nonrandom trend to lower amplitudes or conduction velocities is present, it may be revealed by a summary nerve conduction score. In a group of normal subjects, peroneal, sural, ulnar, and superficial radial nerves were studied; age- and height-related F-wave and soleus H-reflex latencies were also examined. Z-scores of distal latencies, amplitudes, conduction velocities, F-wave latencies, and H-index were averaged in order to obtain three electroneurography (ENG) indices: a simple arithmetic (ENG index 1) and two weighted means (index 2 and index 3), assigning a double or triple weight to lower limb z-scores. Reference limits were established using multiple regression equations of ENG indices against age and height. This technique could be useful in providing a better cut-off between normal and diseased populations and in improving test-retest variability of NCS when follow-up studies are required.  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