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   100530篇
  免费   29392篇
  国内免费   1072篇
耳鼻咽喉   2461篇
儿科学   2856篇
妇产科学   2407篇
基础医学   2694篇
口腔科学   5084篇
临床医学   25958篇
内科学   25279篇
皮肤病学   3324篇
神经病学   12287篇
特种医学   3723篇
外科学   18535篇
综合类   231篇
现状与发展   40篇
一般理论   3篇
预防医学   13302篇
眼科学   2261篇
药学   1429篇
  3篇
中国医学   17篇
肿瘤学   9100篇
  2024年   795篇
  2023年   5284篇
  2022年   1336篇
  2021年   2872篇
  2020年   5378篇
  2019年   2109篇
  2018年   6993篇
  2017年   7379篇
  2016年   7971篇
  2015年   8044篇
  2014年   10524篇
  2013年   12139篇
  2012年   3847篇
  2011年   3604篇
  2010年   6826篇
  2009年   9101篇
  2008年   3517篇
  2007年   2394篇
  2006年   3575篇
  2005年   2109篇
  2004年   1512篇
  2003年   1170篇
  2002年   1080篇
  2001年   1904篇
  2000年   1246篇
  1999年   1802篇
  1998年   2072篇
  1997年   1918篇
  1996年   1971篇
  1995年   1697篇
  1994年   1091篇
  1993年   925篇
  1992年   829篇
  1991年   720篇
  1990年   569篇
  1989年   593篇
  1988年   560篇
  1987年   438篇
  1986年   412篇
  1985年   371篇
  1984年   288篇
  1983年   332篇
  1982年   239篇
  1981年   211篇
  1980年   130篇
  1978年   137篇
  1977年   136篇
  1976年   96篇
  1974年   104篇
  1972年   97篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
21.
Psychological Consequences of Food Restriction   总被引:1,自引:0,他引:1  
A review of the literature and research on food restriction indicates that inhibiting food intake has consequences that may not have been anticipated by those attempting such restriction. Starvation and self-imposed dieting appear to result in eating binges once food is available and in psychological manifestations such as preoccupation with food and eating, increased emotional responsiveness and dysphoria, and distractibility. Caution is thus advisable in counseling clients to restrict their eating and diet to lose weight, as the negative sequelae may outweigh the benefits of restraining one's eating. Instead, healthful, balanced eating without specific food restrictions should be recommended as a long-term strategy to avoid the perils of restrictive dieting. J Am Diet Assoc. 1996; 96:589-592.  相似文献   
22.
Summary: This is the first report of the largest study of blood pressure measurement in pregnancy in a New Zealand population using standardized definitions and methodology. Over 3,800 women who delivered in an 8-month period in the Wellington region were included in the study. Blood pressure measurement and the presence of oedema and proteinuria were recorded from booking until delivery and in the puerperium. Only 2.7% of women were unable to be contacted after delivery for details on outcomes. The results established normal ranges for blood pressure throughout pregnancy. The data show that Mood pressure greater than 140/90 until 35 weeks' gestation is outside 2 standard deviations at all gestations and justifies using these measurements as the definition of hypertension in pregnancy. The fall in blood pressure in the 2nd trimester was less than 1 mm Ffg per week in both the systolic and diastolic pressures. This fall was smaller than previously recorded in other studies. Gestational hypertension was the commonest blood pressure abnormality occurring in 15.2% of the population. This represented 69% of the pregnant women with a hypertensive disorder. The overall incidence of both gestational hypertension and preeclampsia was 18.5% which is higher than reported in other parts of the world. In this study obesity was significantly associated with hypertensive disorders in pregnancy. An arm circumference of >33 cm, one of the measurements of obesity, was found in 6.8% of the study population. Even after the effect of arm circumference was taken into account, hypertensive disorders were also more common in Pacific Island women. Ankle oedema was significantly associated with the development of both gestational hypertension and preeclampsia but the incidence of oedema was noted in only 11.9% of the subjects.  相似文献   
23.
Entering the postmodern world in which society is confronting crossroads, paradoxes, and complexity, the health care system is encountering a transformation more comprehensive and revolutionary than has ever been seen before. Analysis of the state of nursing vis a vis these transformations indicates that the current paradigm does not ensure the existence of the profession in the postmodern health care system. That is because of increased difficulties in consolidating the economic and quality issues into the core of nursing, and in understanding the complexity inherent in health related situations.  相似文献   
24.
Society often expects mothers and fathers to share equally in the perinatal grief process because the child was a common bond between them. Unfortunately, in perinatal grief, this is not always the case. The mother and the father can experience incongruent grieving and use discordant coping mechanisms. It is important to evaluate these differences to facilitate communication between the distraught parents. Improved communication can in turn facilitate the grieving process.  相似文献   
25.
26.
27.
Directors of nursing at 23 nursing homes with Alzheimer's units in Southwestern Pennsylvania completed a self‐reported survey of 12 questions. Responses from the self‐administered questionnaires (100% response rate) revealed a wide variation in the staff categories assessing the oral health status of newly admitted residents with AD. The respondents described oral examinations that were incomplete when compared to the oral indicators listed in the Minimum Data Set. All nursing homes reported that oral hygiene was provided each day. The number of residents in a facility had a significant effect on the frequency of oral hygiene provided. Only 52% of the facilities reported yearly oral examinations for this population. According to the respondents, dental treatment was typically performed on‐site. The oral health care costs were paid by Medicare, Medicaid, the residents/family members, or by other undescribed resources. Insufficient time, staff, and training, as well as uncooperative behavior, were identified as barriers to optimum oral health care for residents with AD. Additional staff, specialized training, and increased government reimbursement were suggested to improve the oral health care for this group of older adults. For future studies, review of medical records and on‐site evaluation of the oral health care at these facilities should be required to verify the reported practices.  相似文献   
28.
We investigated the degree and time course of neutrophil sequestration into human lungs during cardiac operations. At the same time, measurement of the concentration of peroxidation products in the plasma was used as an index of oxidant free radical activity. The study was performed in two groups of patients. Group A (n = 11) had studies extending over the entire operative period and showed a highly significant sequestration of neutrophils into the lung, together with a highly significant (p less than 0.001) rise in peroxidation products from 2.8 +/- 0.12 nmol/ml(mean +/- standard error of the mean)before bypass to a peak of 5.05 +/- 0.13 nmol/ml at the end of bypass. As these changes occurred only during the time after release of the aortic cross-clamp, we investigated this period in more detail in a second group of patients (Group B, n = 7). Results from this group showed that significant release of peroxidation products occurred at the same time as pulmonary neutrophil sequestration. This study has produced evidence of increased oxidant activity in the lung associated with cardiac operations. Nevertheless, it is not known whether the neutrophils sequestered into the lung alone induced the increased activity. Similarly, whether neutrophil-derived oxidant species are the sole cause of lung tissue injury remains unproved.  相似文献   
29.
30.
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