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   563篇
  免费   27篇
  国内免费   7篇
耳鼻咽喉   1篇
儿科学   39篇
妇产科学   3篇
基础医学   42篇
口腔科学   18篇
临床医学   43篇
内科学   150篇
皮肤病学   8篇
神经病学   9篇
特种医学   79篇
外科学   73篇
综合类   62篇
预防医学   20篇
眼科学   8篇
药学   22篇
肿瘤学   20篇
  2024年   1篇
  2023年   2篇
  2022年   5篇
  2021年   6篇
  2020年   5篇
  2019年   3篇
  2018年   7篇
  2017年   4篇
  2016年   10篇
  2015年   16篇
  2014年   11篇
  2013年   17篇
  2012年   10篇
  2011年   13篇
  2010年   22篇
  2009年   34篇
  2008年   12篇
  2007年   25篇
  2006年   35篇
  2005年   11篇
  2004年   10篇
  2003年   3篇
  2002年   7篇
  2001年   12篇
  2000年   8篇
  1999年   15篇
  1998年   42篇
  1997年   32篇
  1996年   40篇
  1995年   17篇
  1994年   18篇
  1993年   22篇
  1992年   4篇
  1991年   9篇
  1990年   6篇
  1989年   10篇
  1988年   26篇
  1987年   9篇
  1986年   8篇
  1985年   17篇
  1984年   9篇
  1983年   4篇
  1982年   3篇
  1981年   3篇
  1980年   3篇
  1977年   3篇
  1976年   5篇
  1975年   3篇
排序方式: 共有597条查询结果,搜索用时 31 毫秒
591.
592.

Background

Nasal modes of respiratory support cause variable amounts of gastric dilatation which may increase gastro-oesophageal reflux (GER) in preterms. To compare the incidence of GER in nasally ventilated, preterm babies with controls (babies not on ventilation). Type of study: A prospective, observational comparative study.

Method

Twenty-three preterm babies of gestational age 28–36 weeks and weight ranging between 1,000 g and < 2,500 g on either nasal continuous positive airway pressure (nCPAP) or nasal intermittent positive pressure venti-lation (nIPPV) were assessed for GER. They were compared with controls not on ventilation some of who were test babies when off ventilation (subgroup A) and some were unrelated babies not on ventilator but matched for gestational age and weight with test babies (subgroup B). All babies were subjected to continuous, oesophageal pH monitoring with dual sensor (upper and lower oesophageal) catheters. Reflux index (RI) was calculated as the percentage of study time the lower oesophageal pH was < 4. Primary outcome was the RI in the test and controls groups. Secondary outcome was the temporal relation of the reflux with symptoms if any. Numerical data were shown as mean with standard deviation and statistical comparisons were done using the χ2-test, Fischer test, and t-test wherever applicable.

Results

The RI was higher in ventilated babies as compared to the control group, particularly in the subgroup A, where test babies formed their own controls. Grade IV reflux (7 cases) was seen only in the ventilated babies. There was no difference in the incidence of GER in babies on nCPAP as compared with nIPPV. Grade IV reflux could not be reliably predicted by RI alone. No definite temporal relation between episodes of reflux and symptoms could be determined in this study.

Conclusion

There is an increase in GER in preterms on nasal modes of ventilation. A combination of upper (pharyngeal) and lower oesophageal sensors are preferred to a single lower oesophageal sensor when assessing GER by oesophageal pHmetry in neonates.  相似文献   
593.
594.
While disorders of neuronal migration are associated with as much as 25% of recurrent childhood seizures, few of the genes required to establish neuronal position in cerebral cortex are known. Subcortical band heterotopia (SBH) and lissencephaly (LIS), two distinct neuronal migration disorders producing epilepsy and variable cognitive impairment, can be inherited alone or together in a single pedigree. Here we report a new genetic locus, XLIS, mapped by linkage analysis of five families and physical mapping of a balanced X;2 translocation in a girl with LIS. Linkage places the critical region in Xq21-q24, containing the breakpoint that maps to Xq22.3-q23 by high-resolution chromosome analysis. Markers used for somatic cell hybrid and fluorescence in situ hybridization analyses place the XLIS region within a 1 cM interval. These data suggest that SBH and X-linked lissencephaly are caused by mutation of a single gene, XLIS, that the milder SBH phenotype in females results from random X-inactivation (Lyonization), and that cloning of genes from the breakpoint region on X will yield XLIS.   相似文献   
595.
Few studies exist on the physiological changes in the concentrations of growth hormone (GH), insulin-like growth factors (IGF) and IGF-binding proteins (IGFBP) within the menstrual cycle, and some controversy remains. We therefore decided to study the impact of endogenous sex steroids on the GH-IGF-IGFBP axis during the ovulatory menstrual cycle in 10 healthy women (aged 18-40 years). Blood sampling and urinary collection was performed every morning at 0800 h for 32 consecutive days. Every second day the subjects were fasted overnight before blood sampling. Follicle stimulating hormone, luteinizing hormone (LH), oestradiol, progesterone, IGF-I, IGFBP-3, sex hormone-binding globulin, dihydroepiandrosterone sulphate and GH were determined in all samples, whereas insulin and IGFBP-1 were determined in fasted samples only. Serum IGF-I concentrations showed some fluctuation during the menstrual cycle, with significantly higher values in the luteal phase compared to the proliferative phase (P < 0.001). Mean individual variation in IGF-I concentrations throughout the menstrual cycle was 13.2% (SD 4.3; range 0.1-18.3%). There were no cyclic changes in IGFBP-3 serum concentrations and no differences in IGFBP-3 concentrations between the luteal and the proliferative phases. Mean individual variation in IGFBP- 3 concentrations throughout the menstrual cycle was 8.8% (SD 2.7; range 3.2-14.1). IGFBP-1 concentrations were inversely associated with insulin concentrations, and showed a significant pre-ovulatory increase that returned to baseline at the day of the LH surge. Fasting insulin concentrations showed large fluctuations throughout the menstrual cycle without any distinct cyclic pattern. No cyclic changes in urinary GH excretion during menstrual cycle were detected. We conclude that, although IGF-I concentrations are dependent on the phase of the menstrual cycle, the variation in IGF-I concentrations throughout the menstrual cycle is relatively small. Therefore, the menstrual cycle does not need to be considered when evaluating IGF-I or IGFBP-3 serum values in women suspected to have GH deficiency.   相似文献   
596.
Background  There are concerns that there is no uniform approach towards the management of vitiligo.
Objectives  To explore attitudes and strategies for the management of vitiligo among dermatologists.
Methods  A self-administered questionnaire containing 22 questions was distributed to 160 dermatologists attending a national dermatology conference in 2007.
Results  One hundred and twelve dermatologists responded to the questionnaire (70% response rate). We had 105 completed questionnaires (seven were excluded due to incompleteness). Active treatment of vitiligo was recommended by 96% in more than half of patients, while 79% recommended treatment at non-visible sites. Repigmentation was regarded as main treatment goal by 54%. Mid-potent topical steroids were widely prescribed for focal vitiligo (72% in children and 65% in adults). Use of tacrolimus and pimecrolimus was limited. The most common used phototherapy was 'narrowband ultraviolet B' (NBUVB; 36% and 40% for generaliased vitiligo in children and adults, respectively). The use of oral psoralen plus UVA (PUVA) was limited (8% for generalized vitiligo in adults). Few respondents (1–8% for different types of vitiligo) prescribed outdoor topical PUVA. Vitiligo surgery was advised mainly for segmental type (18% in adults and 5% in children). Depigmentation was the first option for universal vitiligo by 50% and 30% in adults and children, respectively.
Conclusions  Most dermatologists are enthusiastic about active treatment of vitiligo even in hidden sites. Overall, the most two common treatment modalities were topical steroids and NBUVB. Vitiligo surgery is underutilized. Development of national practice guidelines is needed.  相似文献   
597.
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