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   5732篇
  免费   558篇
  国内免费   94篇
耳鼻咽喉   20篇
儿科学   959篇
妇产科学   211篇
基础医学   406篇
口腔科学   68篇
临床医学   852篇
内科学   441篇
皮肤病学   11篇
神经病学   351篇
特种医学   72篇
外科学   314篇
综合类   483篇
预防医学   1638篇
眼科学   8篇
药学   375篇
  4篇
中国医学   104篇
肿瘤学   67篇
  2024年   11篇
  2023年   115篇
  2022年   272篇
  2021年   404篇
  2020年   271篇
  2019年   251篇
  2018年   234篇
  2017年   227篇
  2016年   203篇
  2015年   198篇
  2014年   329篇
  2013年   392篇
  2012年   284篇
  2011年   381篇
  2010年   261篇
  2009年   236篇
  2008年   224篇
  2007年   236篇
  2006年   186篇
  2005年   166篇
  2004年   127篇
  2003年   117篇
  2002年   99篇
  2001年   111篇
  2000年   88篇
  1999年   78篇
  1998年   63篇
  1997年   52篇
  1996年   46篇
  1995年   50篇
  1994年   68篇
  1993年   33篇
  1992年   39篇
  1991年   36篇
  1990年   31篇
  1989年   31篇
  1988年   35篇
  1987年   32篇
  1986年   37篇
  1985年   59篇
  1984年   41篇
  1983年   37篇
  1982年   41篇
  1981年   36篇
  1980年   23篇
  1979年   17篇
  1978年   24篇
  1977年   10篇
  1976年   12篇
  1975年   10篇
排序方式: 共有6384条查询结果,搜索用时 15 毫秒
11.
Breast feeding has nutritional, immunologic and antiallergicadvantages for the infant. Although it has been widely recommendedthat infants be exclusively breast fed until 4–6 monthsof age, only about half of all Australian babies currently receiveextended breast feeding. The present study evaluated an intensiveprogramme designed to increase the proportion ofprimi-parousmothers who breast fed for 4 months or longer. Women who registeredwith the hospital at least 20 weeks before delivery and whointended to breastfeed were eligible for the study. Two hundredand thirty-five women were allocated to receive either usualcare or an intensive breast feeding programme when they registeredwith the hospital. The intensive programme consisted of writtenmaterials, and group and individual sessions with a lactationcounsellor. It also included a visit from a breastfeeding consultantwhile in hospital after the birth and contact on return home.Women were followed up 6 weeks and 4 months after delivery.There were no significant differences in breastfeeding ratesbetween the control and intervention groups at either follow-uppoint. Breast feeding until 4 months was more likely among womenwhose baby did not receive a bottle feed while still in hospitaland who did not smoke, use the combined oral contraceptive pillor introduce solid food before 4 months. Those mothers who enjoyedand felt satisfied with breastfeeding were more likely to continueto 4 months. It seems likely that programmes designed to increasebreastfeeding will need to address underlying factors such ashospital policy rather than simply providing more health education.  相似文献   
12.
Recent evidence suggests that a variety of hypothalamic neuropeptides may mediate interneuronal communication to coordinate diverse neuroendocrine and behavioral functions. In this work, we describe the effects of neuropeptide Y (NPY) on feeding and sexual behaviors. We observed that central administration of bolus NPY stimulated a robust, dose-related feeding response in satiated male and female rats. Continuous NPY receptor activation also evoked dose-related, intermittent feeding in a manner normally observed during nocturnal feeding. It appears that the paraventricular nucleus in the hypothalamus may be the primary site of NPY action because the anticipated reciprocal changes in NPY concentrations, in response to food deprivation followed by ad libitum food intake, occurred only in this site. Additional findings revealed that NPY-induced feeding may follow either substantial reduction or complete restraint of an inhibitory influence on feeding mediated by alpha 2-adrenoreceptor systems in satiated rats. Further, NPY was found to suppress male and female sexual behaviors. The suppressive effects on sexual behavior were apparent prior to or at the time of the onset of feeding after NPY administration. These observations may provide a neurochemical basis for clinical and animal studies on disorders of feeding associated with diminished reproductive functions.  相似文献   
13.
产后4个月内未能坚持纯母乳喂养的因素分析   总被引:4,自引:0,他引:4  
通过239对母婴产后4个月的跟踪随访发现,在130位母亲未能自始至终坚持纯母乳喂养的因素中,最主要的是自觉奶量不够或者因孩子哭吵、怕孩子吃不饱而添加辅助液体或食品,其次是按旧习惯从出生后3个月起添加米糊类食品,以及医务人员的错误指导和母亲上班等。纯母乳喂养的关键在于必须排除一切干扰,增强母亲的信心。因此,尽快转变旧观念,大力宣传出生后4~6个月纯母乳喂养的重要性,普及泌乳生理知识和哺乳中常见问题的处理方法,加强随访工作,是提高4个月内纯母乳喂养率的重要措施。  相似文献   
14.
极低出生体重儿两种喂养效果观察   总被引:4,自引:0,他引:4  
目的:探讨极低出生体重儿(VLBW)的早期微量持续鼻饲喂养(CNG)与间断鼻饲喂养(ING)的喂养耐受性及喂养效果.方法:将60例VLBW进行随机分组,CNG组起始奶量1-2ml/h,以后泵速增加1-2ml/h.ING组奶量以1-2ml/kg开始, 以后每天增加1-2ml/kg/次.所有VLBW均同时进行部分静脉营养,直至达到完全胃肠道喂养时间(FEF).对比两组喂养不耐受性、达到FEF、停止静脉补液时间及黄疸持续时间.结果:CNG组较ING组患儿发生腹胀、呕吐者明显减少(P<0.05),黄疸持续时间、吸吮动作出现时间及住院时间较对照组明显缩短(P<0.05),但两组体重增长情况统计学无差异(P>0.05).结论:CNG更适合VLBW的早期微量喂养.  相似文献   
15.
Fourteen adult patients (mean age 22.5 years, range 18–35) with cystic fibrosis undertook nocturnal nasogastric feeding for a mean period of 14.7 (range 6–18) months consuming an average of 1042 ml of a high energy feed on five nights of each week. Following this protocol all patients gained weight (mean weight gain 5.4 kg, range 2–17). For the group as a whole, lung function remained stable during the period of feeding; however a significant correlation between improvement in lung function and weight gain was demonstrated. Hyperglycaemia during feeding in this adult population was common (9/14, 64%) but was easily controlled with insulin therapy.  相似文献   
16.
Thirty mothers, attending either a paediatric clinic at a Government hospital or a private paediatrician's surgery, both in Tirupati, Andhra Pradesh, South East India, were questioned about their infant feeding practices. A sample of milk from their child's bottle was requested and subsequently analysed for the presence of dilution. Over-dilution, defined as less than 75% of the standard concentration, was found to be common (P<.05). No significant correlations were found between the incidence of over-dilution and either family income or educational status of the mothers due to the small sample size. The study suggests the need for practical education on the reconstitution of milk feeds.  相似文献   
17.
18.
An automated method was used to record the temporal pattern of feeding of lines of mice selected over 15 generations for high and low body weight (L-mice and S-mice, respectively). Both L-mice and S-mice eat in meals concentrated during the night, and meal frequency is similar in the two lines, but L-mice consume much larger meals, each made up of many more separate feeding bouts. The outbred strain from which the selected lines were derived has a similar basic pattern of feeding in meals, which becomes like that of L-mice when the animal's thermogenic metabolic rate is high, and like that of S-mice when it is low, suggesting that the differences between the feeding patterns of the two selected lines are a secondary consequence of alterations in whole body metabolic rate.  相似文献   
19.
At the age of 28 days, male Sprague-Dawley rats received bilateral electrolytic lesions in the ventromedial (VMN) and dorsomedial (DMN) hypothalamic nuclei, repectively. Sham-operated rats served as controls. Food intake and body weight gains were measured for 13 days at the beginning of the light period (0800–2000 hr) and prior to the start of the dark period (2000-0800 hr). Both types of hypothalamic lesions caused a disruption of the naturally occurring diurnal feeding and weight gaining cycles. In accordance with previous data, the VMN rats remained normophagic and made normal weight gains while DMN animals were hypophagic and gained weight subnormally; linear growth was reduced in both types of lesioned animals, but only the VMN rats became obese. The data suggest the existence in the medial hypothalamus of an area that is involved in feeding and weight gaining cycles. From the standpoint of overall-caloric intake, this area consists of two types of neuronal assemblies that differ fuctionally as profoundly as they are anatomically separate.  相似文献   
20.
The effects, on operant feeding, of injection into the lateral cerebral ventricle of 50 μmoles CaCl2, 4 mmoles D-glucose, 2-deoxy-D-glucose (2DG) or xylose, or NaCl, have been studied in five pigs. All the sugars and CaCl2 were given in 1 ml of normal saline. Each of the sugar solutions produced transient drinking. Only CaCl2 and 2DG significantly increased food intake during the hour following injection. The results show that the mechanism by which the pig responds to intracerebroventricular 2DG is similar to that of the rat and different from that of the sheep.  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