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   746篇
  免费   60篇
  国内免费   7篇
儿科学   29篇
妇产科学   23篇
基础医学   72篇
口腔科学   8篇
临床医学   55篇
内科学   138篇
皮肤病学   5篇
神经病学   25篇
特种医学   88篇
外科学   142篇
综合类   19篇
预防医学   137篇
眼科学   6篇
药学   39篇
肿瘤学   27篇
  2021年   6篇
  2020年   6篇
  2019年   14篇
  2018年   16篇
  2017年   3篇
  2016年   12篇
  2015年   13篇
  2014年   9篇
  2013年   22篇
  2012年   22篇
  2011年   21篇
  2010年   27篇
  2009年   23篇
  2008年   27篇
  2007年   28篇
  2006年   26篇
  2005年   24篇
  2004年   20篇
  2003年   26篇
  2002年   31篇
  2001年   23篇
  2000年   11篇
  1999年   24篇
  1998年   27篇
  1997年   29篇
  1996年   31篇
  1995年   24篇
  1994年   26篇
  1993年   21篇
  1992年   18篇
  1991年   11篇
  1990年   18篇
  1989年   16篇
  1988年   10篇
  1987年   12篇
  1986年   13篇
  1985年   9篇
  1984年   4篇
  1983年   5篇
  1982年   4篇
  1981年   9篇
  1980年   8篇
  1979年   6篇
  1978年   9篇
  1977年   6篇
  1976年   10篇
  1975年   4篇
  1971年   3篇
  1962年   5篇
  1914年   3篇
排序方式: 共有813条查询结果,搜索用时 15 毫秒
1.
2.
3.
This paper investigates the association between individually measured socioeconomic status (SES) and all-cause survival in colorectal cancer patients, and explores whether factors related to the patient, the disease, or the surgical treatment mediate the observed social gradient.  相似文献   
4.
5.
6.
Rigor and resistance to stretch in vertebrate smooth muscle   总被引:2,自引:0,他引:2  
  相似文献   
7.
8.
BACKGROUND: The less favorable trend in smoking prevalence in women compared to men may be due to lower cessation rates. We analyzed determinants of spontaneous smoking cessation with particular reference to gender differences. METHODS: Data on smoking were collected by questionnaire in three samples of the adult population, examined for the first time at intervals between 1976 and 1984. In total 11,802 (59%) subjects were smokers, and 9085 of them attended a reexamination after 5 years. Ten to 16 years later 6053 were examined once again. Logistic regression was performed to study the relation of determinants to having quit after 5 and 10-16 years. RESULTS: The prevalence of quitting was 12 and 22% at first and second follow-up, respectively. At both reexaminations, quitting smoking was positively associated with male sex and cigar smoking and negatively associated with the amount of tobacco smoked, inhalation, and alcohol consumption. Furthermore, in women, smoking cessation was positively associated with level of education and body mass index (BMI). Smoking cessation was not affected by cohabitation status, leisure activity, or bronchitis symptoms. CONCLUSIONS: Smoking cessation initiatives should be targeted at heavy cigarette smokers, and at women, in particular the lean and poorly educated.  相似文献   
9.
The purpose of the present study was to evaluate the capacity of the 'Determine Your Nutritional Health' Checklist (NSI Checklist) and the 'Mini Nutritional Assessment' (MNA) methods to predict nutrition-related health problems. Data were from the Danish part of the 'Survey in Europe of Nutrition in the Elderly, a Concerted Action' (SENECA) baseline survey from 1988, and the follow-up study from 1993. Based on the baseline survey thirty-nine (19.3%) of the subjects were classified at high nutritional risk, 103 (51%) were considered at moderate nutritional risk and sixty (29.7%) were within the 'good' range according to the criteria in the NSI Checklist. With the MNA, 171 subjects were classified according to their nutritional risk into a well-nourished group, comprising 78.4%, and a group who were at risk of undernutrition, comprising 21.6% at baseline. A total of 115 subjects participated in the follow-up study. The mortality rate and the prevalence of various morbidity indicators were compared between the different risk groups. The analysis showed that subjects with a high MNA score (> or = 24) had significantly lower mortality (rate ratio estimate: 0.35; 95% Cl 0.18, 0.66) compared with subjects with a low MNA score (< or = 23.5). In contrast, the NSI Checklist score was not a significant predictor of mortality (rate ratio estimate: 1.45; 95% Cl 0.78, 2.71). The sixteen Danes judged to be at high nutritional risk by the NSI Checklist in 1988, had more acute diseases (P < 0.001) than the rest of the participants, between 1988 and 1993. No significant differences were found in the participation rates, hospitalization rates, physician visits, need of help or weight loss between the groups. The thirteen Danes judged to be at risk of undernutrition in 1988 by the MNA, had a lower participation rate (P < 0.01) and higher occurrence of acute disease (P < 0.05), need of help (P < 0.05), and weight loss (P < 0.001) than the well-nourished group, between 1988 and 1993. No significant differences were found in hospitalization rates and physician visits between the two groups. In conclusion, the results indicate that modified versions of the NSI Checklist and the MNA are capable of identifying a group of 70-75-year-old subjects with increased risk of certain nutrition-related health problems. Further, an MNA score < or = 23.5 predicts mortality in a Danish population.  相似文献   
10.
OBJECTIVE: Because the survival rate has increased for extremely low birth weight neonates, many have raised the concern that the rate of developmental disability among survivors will also increase. To address this concern, we analyzed changes over time in survival and major neurosensory impairment in a sample of extremely low birth weight infants born between July 1, 1979, and June 30, 1994. METHODS: The study sample included 513 infants with birth weights of 501 to 800 g who were cared for in either of the two neonatal intensive care units that serve a 17-county region in northwest North Carolina and who were born to mothers residing in that region. At 1 year of age (corrected for gestation), survivors were examined by a pediatrician and were tested using the Bayley Scales of Infant Development. Major neurosensory impairment was defined as cerebral palsy, a Bayley Mental Developmental Index <68, or blindness. A total of 209/216 (97%) of survivors were examined at 1 year of age. Epoch of birth was defined as follows: epoch 1, July 1, 1979 to June 30, 1984; epoch 2, July 1, 1984 to June 30, 1989; and epoch 3, July 1, 1989 to June 30, 1994. RESULTS: Survival rates for epochs 1, 2, and 3 were, respectively, 24/120 (20%), 63/175 (36%), and 129/218 (59%). In contrast, the proportions with a major neurosensory impairment did not increase over time; rates for successive epochs were 6/24 (25%), 17/61 (28%), and 26/124 (21%). Rates of cerebral palsy were 3/24 (13%), 12/61 (20%), and 9/124 (7%); rates of delayed mental development were 4/24 (17%), 12/61 (20%), and 17/124 (14%); and rates of blindness were 2/24 (8%), 0/62, and 5/124 (4%), respectively. CONCLUSIONS: This analysis suggests that the increasing survival of extremely low birth weight neonates since the late 1970s has not resulted in an increased rate of major developmental problems identifiable at 1 year of age.  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