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   6692篇
  免费   616篇
  国内免费   40篇
耳鼻咽喉   51篇
儿科学   262篇
妇产科学   85篇
基础医学   882篇
口腔科学   238篇
临床医学   877篇
内科学   1384篇
皮肤病学   97篇
神经病学   550篇
特种医学   297篇
外科学   953篇
综合类   173篇
一般理论   2篇
预防医学   527篇
眼科学   93篇
药学   352篇
中国医学   6篇
肿瘤学   519篇
  2023年   39篇
  2022年   46篇
  2021年   105篇
  2020年   68篇
  2019年   99篇
  2018年   130篇
  2017年   123篇
  2016年   137篇
  2015年   152篇
  2014年   192篇
  2013年   272篇
  2012年   316篇
  2011年   300篇
  2010年   229篇
  2009年   207篇
  2008年   265篇
  2007年   315篇
  2006年   279篇
  2005年   237篇
  2004年   250篇
  2003年   228篇
  2002年   200篇
  2001年   193篇
  2000年   177篇
  1999年   198篇
  1998年   169篇
  1997年   150篇
  1996年   141篇
  1995年   118篇
  1994年   113篇
  1993年   75篇
  1992年   119篇
  1991年   115篇
  1990年   125篇
  1989年   157篇
  1988年   133篇
  1987年   116篇
  1986年   105篇
  1985年   125篇
  1984年   85篇
  1983年   67篇
  1982年   64篇
  1981年   56篇
  1980年   48篇
  1979年   60篇
  1978年   47篇
  1977年   36篇
  1975年   31篇
  1973年   49篇
  1969年   34篇
排序方式: 共有7348条查询结果,搜索用时 15 毫秒
91.
92.
The impact of a pharmacy officer on patient compliance and blood pressure control on a deployed nuclear-powered aircraft carrier for a 2-week at-sea period was evaluated. Before any counseling by a pharmacy officer, 43 crewmembers on chronic medications anonymously completed a compliance questionnaire. The pharmacy officer then counseled these crewmembers. A follow-up compliance questionnaire was completed 2 weeks later. After counseling, compliance had increased 58% (p < 0.0001) from compliance measured before counseling. The pharmacy officer also initiated therapeutic interventions. Among 26 crewmembers diagnosed as hypertensive, preintervention blood pressure (BP) measurements were obtained. Ten to 14 days after the initial BP measurement, BP was remeasured. After intervention, 31% (p < 0.02) more crewmembers were at BP goal compared with before intervention. A pharmacy officer, working closely with a medical officer, improved patient compliance and blood pressure control. One problem identified was that these warships require computer software that can prospectively identify drug-drug interactions.  相似文献   
93.
BACKGROUND: Standardised measures of behaviour have failed to detect short term improvement in children with autism following treatment with secretin. However, it is possible that standardised measures are insensitive to dimensions of child behaviour that are nonetheless detectable by parents. AIM: To determine the ability of parents of children with autism to guess, under double blind conditions, whether their child had received secretin or placebo. METHODS: 2x2 crossover randomised blinded study, comparing the effect of synthetic human secretin 2 U/kg to placebo (saline). Sixty two children with autism (aged 43-103 months) were randomly allocated to two groups: group 1 received placebo, followed six weeks later by secretin, and group 2 received secretin followed by placebo. At the conclusion of the study, parents were asked to guess their child's group assignment. RESULTS: Twenty seven families guessed their child's group assignment correctly and 27 guessed incorrectly. In 48 instances, parents based their guess on perceived improvement; in six cases, parents based their guess on perceived deterioration. Six families saw no difference after either infusion, and offered no guess. One family dropped out after the first infusion, and one family was lost to follow up after the second infusion. CONCLUSION: In a controlled setting, parents of young children with autism are unable to distinguish the short term behavioural effects of secretin from placebo.  相似文献   
94.
BACKGROUND: It is unclear why some morbidly obese individuals have waking alveolar hypoventilation while others with similar obesity do not. Some evidence suggests that patients with the obesity hypoventilation syndrome (OHS) may have a measurable premorbid impairment of ventilatory chemoresponsiveness. Such an impairment of ventilatory chemoresponsiveness in OHS, however, may be an acquired and reversible consequence of severe obstructive sleep apnoea (OSA). We hypothesised that, in patients with OHS who do not have coincident severe OSA, there may be a familial impairment in ventilatory responses to hypoxia and hypercapnia. METHODS: Sixteen first degree relatives of seven patients with OHS without severe OSA (mean (SD) age 40 (16) years, body mass index (BMI) 30 (6) kg/m(2)) and 16 subjects matched for age and BMI without OHS or OSA were studied. Selection criteria included normal arterial blood gas tensions and lung function tests and absence of sleep apnoea on overnight polysomnography. Ventilatory responses to isocapnic hypoxia and to hyperoxic hypercapnia were compared between the two groups. RESULTS: The slope of the ventilatory response to hypercapnia was similar in the relatives (mean 2.33 l/min/mm Hg) and in the control subjects (2.12 l/min/mm Hg), mean difference 0.2 l/min/mm Hg, 95% confidence interval (CI) for the difference -0.5 to 0.9 l/min/mm Hg, p=0.5. The hypoxic ventilatory response was also similar between the two groups (slope factor A: 379.1 l/min * mm Hg for relatives and 373.4 l/min * mm Hg for controls; mean difference 5.7 l/min * mm Hg; 95% CI -282 to 293 l/min * mm Hg, p=0.7; slope of the linear regression line of the fall in oxygen saturation and increase in minute ventilation: 2.01 l/min/% desaturation in relatives, 1.15 l/min/% desaturation in controls; mean difference 0. 5 l/min/% desaturation; 95% CI -1.7 to 0.7 l/min/% desaturation, p=0. 8). CONCLUSION: There is no evidence of impaired ventilatory chemoresponsiveness in first degree relatives of patients with OHS compared with age and BMI matched control subjects.  相似文献   
95.
96.
97.
OBJECTIVE: To evaluate the impact of zinc supplementation on the clinical course, stool weight, duration of diarrhoea, changes in serum zinc, and body weight gain of children with acute diarrhoea. DESIGN: Randomised double blind controlled trial. Children were assigned to receive zinc (20 mg elemental zinc per day) containing multivitamins or control group (zinc-free multivitamins) daily in three divided doses for two weeks. SETTING: A diarrhoeal disease hospital in Dhaka, Bangladesh. PATIENTS: 111 children, 3 to 24 months old, below 76% median weight for age of the National Center for Health Statistics standard with acute diarrhoea. Children with severe infection and/or oedema were excluded. MAIN OUTCOME MEASURES: Total diarrhoeal stool output, duration of diarrhoea, rate of weight gain, and changes in serum zinc levels after supplementation. RESULTS: Stool output was 28% less and duration 14% shorter in the zinc supplemented group than placebo (p = 0.06). There were reductions in median total diarrhoeal stool output among zinc supplemented subjects who were shorter (less than 95% height for age), 239 v 326 g/kg (p < 0.04), and who had a lower initial serum zinc (< 14 mmol/l), 279 v 329 g/kg (p < 0.05); a shortening of mean time to recovery occurred (4.7 v 6.2 days, p < 0.04) in those with lower serum zinc. There was an increase in mean serum zinc in the zinc supplemented group (+2.4 v -0.3 mumol/l, p < 0.001) during two weeks of supplementation, and better mean weight gain (120 v 30 g, p < 0.03) at the time of discharge from hospital. CONCLUSIONS: Zinc supplementation is a simple, acceptable, and affordable strategy which should be considered in the management of acute diarrhoea and in prevention of growth faltering in children specially those who are malnourished.  相似文献   
98.
This study was designed to compare the growth of Pakistani schoolchildren in the UK with the 1990 UK growth standards. Measurements of height, weight, and sitting height were performed on 785 Pakistani schoolchildren aged 5-14 years with the mean values for each age and sex being plotted on the UK growth standards. The results were expressed as SD scores relative to the 1990 reference data. The mean height for the boys was only 0.2 SD scores below the mean for the new growth standards with the mean height for the girls being 0.4 SD scores below the mean. The mean values for weight and body mass index were 0.3 and 0.5 SD scores less than the mean for boys and girls respectively. This study demonstrates that the growth of Pakistani schoolchildren in the UK is comparable to the 1990 UK growth standards with only minor differences. It is not safe to assume that short stature or low body weight in a Pakistani child is due to his or her ethnic background.  相似文献   
99.
The objective of this study was to examine the effects of the intakeof dietary fat upon colorectal cancer risk in a combined analysis of datafrom 13 case-control studies previously conducted in populations withdiffering colorectal cancer rates and dietary practices. Original datarecords for 5,287 cases of colorectal cancer and 10,470 controls werecombined. Logistic regression analysis was used to estimate odds ratios (OR)for intakes of total energy, total fat and its components, and cholesterol.Positive associations with energy intake were observed for 11 of the 13studies. However, there was little, if any, evidence of anyenergy-independent effect of either total fat with ORs of 1.00, 0.95, 1.01,1.02, and 0.92 for quintiles of residuals of total fat intake (P trend =0.67) or for saturated fat with ORs of 1.00, 1.08, 1.06, 1.21, and 1.06 (Ptrend = 0.39). The analysis suggests that, among these case-control studies,there is no energy-independent association between dietary fat intake andrisk of colorectal cancer. It also suggests that simple substitution of fatby other sources of calories is unlikely to reduce meaningfully the risk ofcolorectal cancer.  相似文献   
100.
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