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   775篇
  免费   63篇
  国内免费   15篇
耳鼻咽喉   5篇
儿科学   47篇
妇产科学   11篇
基础医学   103篇
口腔科学   31篇
临床医学   97篇
内科学   166篇
皮肤病学   34篇
神经病学   36篇
特种医学   130篇
外科学   48篇
综合类   42篇
预防医学   24篇
眼科学   5篇
药学   54篇
中国医学   2篇
肿瘤学   18篇
  2023年   4篇
  2022年   4篇
  2021年   13篇
  2020年   12篇
  2019年   17篇
  2018年   11篇
  2017年   17篇
  2016年   17篇
  2015年   23篇
  2014年   25篇
  2013年   33篇
  2012年   16篇
  2011年   11篇
  2010年   46篇
  2009年   42篇
  2008年   19篇
  2007年   26篇
  2006年   18篇
  2005年   17篇
  2004年   13篇
  2003年   14篇
  2002年   11篇
  2001年   11篇
  2000年   20篇
  1999年   12篇
  1998年   44篇
  1997年   40篇
  1996年   36篇
  1995年   23篇
  1994年   33篇
  1993年   30篇
  1992年   8篇
  1991年   7篇
  1990年   6篇
  1989年   19篇
  1988年   16篇
  1987年   17篇
  1986年   10篇
  1985年   8篇
  1984年   5篇
  1983年   10篇
  1982年   13篇
  1981年   9篇
  1980年   14篇
  1978年   4篇
  1977年   14篇
  1976年   7篇
  1975年   5篇
  1956年   4篇
  1955年   3篇
排序方式: 共有853条查询结果,搜索用时 312 毫秒
51.
52.
53.
The extent of length polymorphisms of the heterochromatic and euchromatic segment of the human Y chromosome were investigated in 15 boys with acute leukemia and were compared with 15 normal controls. A greater value of the Yh/F index in relation to controls was established (P < 0.05). The length of the euchromatic segment was also shorter in the patients than the controls (P < 0.05).  相似文献   
54.
ABSTRACT. Serial plasma glucose estimations were performed in 44 light-for-date infants and 17 infants of diabetic mothers fed 2, 3 or 4-hourly with feeds containing 10 % additional carbohydrate in the form of a glucose polymer (Caloreen). In the infants fed 2 and 3-hourly, plasma glucose was higher following the high carbohydrate feeds, particularly immediately before the next feed was due. Given 4-hourly, the high carbohydrate feed had little effect in most light-for-date infants, and in one light-for-date infant and two infants of diabetic mothers the plasma glucose was lower at the end of 4 hours than following normal formula. It is concluded that the addition of glucose polymer to feeds given 2 and 3 hourly has a potentially useful effect in neonates at risk of developing hypoglycaemia, but it cannot be used to increase the feed interval to 4 hours.  相似文献   
55.
A series of 73 hypopharyngeal (Zenker's) diverticula is reported and the choice of treatment and technique of excision are discussed. The problems of excision include operation on an infected site with limited access but few patients are unfit for the procedure. Preoperatively the sac should be packed and the oesophagus stented. The side of approach is unimportant as the condition is essentially midline. Cricopharyngeal myotomy appears to reduce the recurrence rate, possibly by improving coordination of pharyngeal contraction and upper oesophageal relaxation. The use of electrocoagulation is not recommended as 20% of patients require repeated general anaesthesia and the procedure fails in 13%. For all but the smallest pouches, excision is the treatment of choice.  相似文献   
56.
57.
OBJECTIVE: To evaluate pubertal development and peripheral concentrations of gonadotrophins and sex hormones in children with shunted hydrocephalus compared with healthy controls. STUDY DESIGN: 114 patients (52 females, 62 males) and 73 healthy controls (35 females, 38 males) aged 5 to 20 years were analysed for stage of puberty, age at menarche, testicular volume, basal serum follicle stimulating hormone (FSH), luteinising hormone (LH), sex hormone binding globulin (SHBG), testosterone and oestradiol concentrations, and free androgen index. RESULTS: Male gonadal and male and female pubic hair development occurred significantly earlier in the patients than in the controls. The mean age at menarche was significantly lower in the female patients than in their controls (11.7 v 13.2 years; p < 0.001), and lower than it had been for their mothers (v 13.1 years; p < 0.001). Relative testicular volume was higher in the male patients than in their controls (1.2 standard deviation score (SDS) v 0.2 SDS; p < 0.001). The prepubertal patients had higher basal LH (0.13 U/l v 0.08 U/l; p < 0.001) and SHBG (132.3 nmol/l v 109.1 nmol/l; p < 0.01) than the controls. Both the prepubertal and pubertal females had significantly higher basal FSH than their controls (1.57 U/l v 1.03 U/l; p < 0.05, and 4.0 U/l v 2.9 U/l; p < 0.01, respectively). CONCLUSIONS: Hydrocephalic children experience accelerated pubertal maturation, reflected in a younger age at menarche in females and an increased testicular volume in males. This may be because of enhanced gonadotrophin secretion, possibly resulting from unphysiological variations in intracranial pressure.  相似文献   
58.
Six adult patients with growth hormone receptor deficiency (GHRD) (2 men, 4 women) with an identical defect in the growth hormone receptor (GHR) gene, were treated with recombinant human insulin-like growth factor I (IGF-I), 40 μgikg S.C. twice daily, for 7 days. Serum concentrations of IGF peptide and IGF binding protein-3 (IGFBP-3) were measured by specific radioimmunoassays; serum IGFBPs were also measured by Western ligand blotting. The size distribution of both IGF-I and IGF-II was measured in serum following size-exclusion fast-performance liquid chromatography. IGF-I treatment resulted in a normalization of serum IGF-I levels on days 1–7 of treatment and a decrease in serum IGF-II levels. The fall in IGF-II levels and the simultaneous rise in IGF-I levels, however, resulted in an unchanged total serum IGF level. The low IGFBP-3 values did not significantly change during treatment, whereas there was a slight increase in IGFBP-2 levels. Preliminary analysis of size-fractionated sera suggested an increase in IGF-I levels in the 40 and 150 kDa regions at the expense of IGF-II levels. The results suggest that despite the failure of IGF-I treatment to increase IGFBPs significantly, serum IGFBP concentrations were sufficient to maintain normal levels of IGF-I. 0 Laron syndrome, growth hormone receptor deficiency, insulin-like growth factors, insulin-like growth factor binding protein  相似文献   
59.
60.
Characteristic lesions formed by mouse complement were visible in electron micrographs of Escherichia coli cell walls treated with aminoethylisothiouronium bromide and then incubated with normal mouse serum in vitro. However, lesions could not be detected in E. coli cell walls recovered from the blood of normal mice after intravenous injection.

Lesions were not produced by either heated or complement deficient mouse sera in any of the experiments.

After incubation with normal or complement deficient mouse serum E. coli cell walls were surrounded by a layer probably made up of complement components and immunoglobulins. This layer was less evident when the sera had been heated at 56° for 1 hour.

Numerous lesions formed by the in vivo action of guinea-pig complement were found in E. coli cell walls recovered from the animal after intravenous injection.

  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