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   46885篇
  免费   4969篇
  国内免费   115篇
耳鼻咽喉   453篇
儿科学   1295篇
妇产科学   1108篇
基础医学   6982篇
口腔科学   1098篇
临床医学   5811篇
内科学   8647篇
皮肤病学   552篇
神经病学   4490篇
特种医学   1920篇
外国民族医学   57篇
外科学   6046篇
综合类   1018篇
一般理论   43篇
预防医学   5185篇
眼科学   1129篇
药学   3460篇
中国医学   29篇
肿瘤学   2646篇
  2021年   667篇
  2020年   414篇
  2019年   649篇
  2018年   751篇
  2017年   594篇
  2016年   641篇
  2015年   674篇
  2014年   997篇
  2013年   1576篇
  2012年   2053篇
  2011年   2090篇
  2010年   1291篇
  2009年   1122篇
  2008年   1995篇
  2007年   1990篇
  2006年   2014篇
  2005年   1923篇
  2004年   1956篇
  2003年   1724篇
  2002年   1699篇
  2001年   1500篇
  2000年   1614篇
  1999年   1370篇
  1998年   640篇
  1997年   560篇
  1996年   519篇
  1995年   519篇
  1994年   460篇
  1993年   436篇
  1992年   1086篇
  1991年   1130篇
  1990年   1040篇
  1989年   1018篇
  1988年   1029篇
  1987年   896篇
  1986年   881篇
  1985年   849篇
  1984年   711篇
  1983年   596篇
  1982年   384篇
  1981年   373篇
  1980年   353篇
  1979年   662篇
  1978年   517篇
  1977年   446篇
  1976年   422篇
  1975年   384篇
  1974年   438篇
  1973年   435篇
  1972年   377篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
21.
22.
23.
To measure intestinal absorption by using a single, random stool sample, polyethylene glycol (PEG), 1 g/d, and a constant diet were given to healthy infants, with a constant PEG-to-macronutrient ratio. After 10 d equilibration, apparent intestinal absorption of macronutrients was estimated from a standard 3-d metabolic balance and compared with that estimated by using the ratio of PEG to macronutrients in a single random sample of feces. Correlation coefficients for this comparison were 0.649, 0.715, and 0.924 for nitrogen, carbohydrate, and fat, respectively. Additionally, apparent intestinal absorptions estimated from two separate consecutive 3-d metabolic-balance studies were compared, showing correlation coefficients of 0.106, 0.653, and 0.463 for nitrogen, carbohydrate, and fat, respectively. The random sample-marker technique appears to be acceptable for measuring apparent absorption of macronutrients and is at least as accurate as a standard 3-d metabolic-balance study.  相似文献   
24.
Quantitative studies of morbidity, food intake, and somatic growth were done prospectively during 14 mo for 70 children aged 5-18 mo in two Bangladeshi villages. When random-effect regression models were used, monthly changes in weight were inversely related to proportions of days in the month with fever and diarrhea and positively related to energy intake per kilogram body weight. Interestingly, weight changes did not vary with age in this interval. Estimates indicate that increasing energy intakes to the recommended World Health Organization level would have a significantly greater effect on weight gain than would the elimination of diarrhea and fever. With energy at recommended intake and diarrhea and fever prevalence as found in US children, weight gain is predicted to be near that of the international reference population. Therefore, interventions aimed at improving dietary intake may be as important as infection-control programs for improving growth of children in poor developing nations.  相似文献   
25.
Breast pumps are medical devices used to express milk and maintain the milk supply. The purpose of this study was to characterize adverse events reported to the United States Food and Drug Administration (FDA) on breast pumps. Thirty-seven adverse event reports on breast pumps were identified from the Manufacturer and User Facility Device Experience database between 1992 and 2003. Four additional reports were found in the Device Experience Network database from 1992 to 1996. The most commonly reported adverse events for electric breast pumps were pain, soreness, or discomfort; the need for medical intervention; and breast tissue damage. Most frequently reported problems for manual breast pumps were breast tissue damage and infection. Contamination of breast milk during pumping was also reported. Breast pump adverse events are likely underreported to the FDA. Reporting adverse events is important for improving the design and manufacture of breast pumps and subsequently decreasing adverse events.  相似文献   
26.
ABSTRACT Freud's paper on the Schreber Case is considered from a contemporary perspective drawing on the object relations theorists. Some of Winnicott's ideas are used to illustrate how one might understand Schreber's predicament today. Although Freud's views on the role of repressed homosexual longings in the aetiology of Schreber's illness are not endorsed his prescience in the search for meaning in the patient's discourse is applauded.  相似文献   
27.
Many older treatments should not be discarded because of newer modalities. Various dermatologic disorders may be controlled effectively by prescribing these older topical agents.  相似文献   
28.
A variety of nutritional factors influence the bioavailability of calcium and increase a woman's risk of osteoporosis. Eight healthy women completed an 8-week metabolic study designed to investigate the effect of nonalcoholic carbonated beverage consumption on calcium metabolism. Compared with women receiving a control diet, women consuming a diet high in nonalcoholic carbonated beverages demonstrated similar mean serum levels of calcium, ionized calcium, phosphorus, alkaline phosphatase, parathyroid hormone, 1,25-dihydroxyvitamin D3, and osteocalcin. Twenty-four-hour urine volume, creatinine clearance, calcium-creatinine ratio, and phosphorus-creatinine ratio were similar during consumption of the diet high in nonalcoholic carbonated beverages and the control diet. Twenty-four-hour cyclic adenosine monophosphate-creatinine ratio was significantly lower in women consuming the diet high in nonalcoholic carbonated beverage compared with women receiving the control diet (342 +/- 27.4 nmol/mmol vs 409 +/- 22.1 nmol/mmol). Consumption of a diet high in nonalcoholic carbonated beverages on a short-term basis does not appear to affect adversely the serum or urinary markers of calcium metabolism.  相似文献   
29.
The assessment of the medical lethality and intent of suicide attempts has been considered an important area of research for those interested in suicide. The current study examined the usefulness of the Risk-Rescue Rating Scale with 109 adolescent suicide attempters and found a restricted range of variability, which, in turn, resulted in poor interrater reliability on a number of items. Results suggest that the Risk-Rescue Rating Scale is of limited usefulness with adolescents, and alternative approaches to assessing lethality and suicidal intent with this age group are discussed.  相似文献   
30.
Diabetic polyneuropathy   总被引:1,自引:0,他引:1  
  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