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   496篇
  免费   24篇
耳鼻咽喉   8篇
儿科学   25篇
妇产科学   6篇
基础医学   53篇
口腔科学   24篇
临床医学   55篇
内科学   63篇
神经病学   25篇
特种医学   12篇
外科学   132篇
综合类   1篇
预防医学   81篇
眼科学   1篇
药学   21篇
肿瘤学   13篇
  2024年   1篇
  2023年   1篇
  2022年   8篇
  2021年   5篇
  2020年   6篇
  2019年   6篇
  2018年   7篇
  2017年   10篇
  2016年   5篇
  2015年   13篇
  2014年   18篇
  2013年   25篇
  2012年   21篇
  2011年   27篇
  2010年   19篇
  2009年   18篇
  2008年   33篇
  2007年   34篇
  2006年   38篇
  2005年   28篇
  2004年   37篇
  2003年   39篇
  2002年   20篇
  2001年   8篇
  2000年   7篇
  1999年   8篇
  1998年   5篇
  1997年   9篇
  1996年   7篇
  1995年   2篇
  1994年   1篇
  1993年   4篇
  1992年   6篇
  1991年   9篇
  1990年   5篇
  1989年   3篇
  1988年   6篇
  1987年   2篇
  1986年   1篇
  1985年   2篇
  1984年   3篇
  1982年   3篇
  1981年   2篇
  1980年   4篇
  1979年   2篇
  1978年   1篇
  1976年   1篇
排序方式: 共有520条查询结果,搜索用时 15 毫秒
11.
As pregnancy may trigger overweight in women, new means for its prevention are being sought. The aim here was to investigate the effect of individual dietary counselling during and after pregnancy on post‐partum weight and waist circumference up to 4 years post‐partum. A cohort of women (n = 256) were randomized to receive repeated individual dietary counselling by a nutritionist during and after pregnancy, or as controls not receiving dietary counselling, from the first trimester of pregnancy until 6 months after delivery. Counselling aimed to bring dietary intake into line with recommendations, with particular focus on the increase in the intake of unsaturated fatty acids instead of saturated. Pre‐pregnancy weight was taken from welfare clinic records. Weight and waist circumference were measured at 4 years after delivery. The proportion of overweight women increased from 26% prior to pregnancy to 30% at 4 years after delivery among women receiving dietary counselling, as against considerably more, from 32% to 57%, among controls. The prevalence of central adiposity was 31% in women receiving dietary counselling, 64% in controls. Likewise, both the risk of overweight (odds ratio: 0.23, 0.08–0.63, P = 0.005) and central adiposity (odds ratio: 0.18, 0.06–0.52, P = 0.002) were lower in women receiving dietary counselling compared with controls. Repeated dietary counselling initiated in early pregnancy can be beneficial in long‐term weight control after delivery.  相似文献   
12.
13.
14.
15.
Although DNA aneuploidy and high proliferative activity (S-phase fraction, SPF) of tumour cells, measured by flow cytometry, have proved to be indicators of poor prognosis in most solid tumours, there have been conflicting results in lung cancer studies. During a four-year period we studied the prognostic significance of DNA ploidy and SPF in 99 surgically treated lung cancer patients. Flow cytometric analysis was done from archival, formalin-fixed, paraffin-embedded tumour specimens. DNA index and SPF were determined, using MultiCycle software with sliced nuclear correction to compensate for debris. There were 61 DNA diploid and 38 DNA aneuploid tumours. The median SPF was 10.2%. Neither ploidy nor SPF was associated with previously known prognostic factors. Survival was poorer in patients with aneuploid tumours than in the other patients, but the difference was not statistically significant. DNA ploidy and SPF thus do not seem to be useful prognostic indicators in surgically treated lung cancer.  相似文献   
16.
Objectives. We aimed to assess the spontaneous healing of myocardial function after occlusion of a chronically stenosed coronary vessel in a porcine model. Design. Ischemia and infarction was produced by Ameroid constrictor placement and a subsequent ligation of the left circumflex artery. Cardiac MRI and 18FDG-PET were performed one and five weeks later. Ki67 staining was used to identify proliferating cells. Results. Restoration of perfusion defect was detected by MRI (p=0.0065), reduced systolic function of the lateral segment spontaneously recovered (p=0.03). There was also a suggestive raise in impaired ejection fraction (p=0.06). Left ventricular early diastolic filling and peak filling rate were substantially improved (p=0.039 and p=0.0078). Scar size reduced (p=0.03). On the 18FDG-PET, deranged metabolism was alleviated (p=0.03). Cardiomyocytes with positive Ki-67 staining were located principally in the non-infarcted myocardium as compared to the infarction or border areas (p=0.037). Conclusions. We demonstrated spontaneous functional healing of ischemic and infarcted left ventricle, suggesting border zone perfusion recovery. Scar reduction was detected. Different pattern of myocyte proliferation between infarction and non-ischemic myocardium was seen.  相似文献   
17.
Background contextReduced vertebral strength is a clear risk factor for vertebral fractures. Men and women with vertebral fractures often have reduced vertebral size and bone mineral density (BMD). Vertebral strength is controlled by both genetic and developmental factors. Malnutrition and low levels of physical activity are commonly considered to result in reduced bone size during growth. Several studies have also demonstrated the general relationship between BMD and physical activity in the appendicular skeleton.PurposeIn this study, we wanted to clarify the role of physical activity on vertebral bodies. Vertebral dimensions appear to generally be less pliant than long bones when lifetime changes occur. We wanted to explore the association between physical activity during late adolescence and vertebral strength parameters such as cross-sectional size and BMD.Study designThe association between physical activity and vertebral strength was explored by measuring vertebral strength parameters and defining the level of physical activity during adolescence.Patient sampleThe study population consisted of 6,928 males and females who, at 15 to 16 and 19 years of age, responded to a mailed questionnaire inquiring about their physical activity. A total of 558 individuals at the mean age of 21 years underwent magnetic resonance imaging (MRI) scans.MethodsWe measured the dimensions of the fourth lumbar vertebra from the MRI scans of the Northern Finland Birth Cohort 1986 and performed T2* relaxation time mapping, reflective of BMD. Vertebral strength was based on these two parameters. We analyzed the association of physical activity on vertebral strength using the analysis of variance.Results and conclusionsWe observed no association between the level of physical activity during late adolescence and vertebral strength at 21 years.  相似文献   
18.
19.
The aim of this national cross‐sectional study was to explore the prevalence of pressure injuries and incidence of hospital‐acquired pressure injuries, and the relating factors in somatic‐specialised inpatient care in Finland. The study was conducted in 16 (out of 21) Finnish health care organisations offering specialised health care services. Data were collected in 2018 and 2019 from adult patients (N = 5902) in inpatient, emergency follow‐up, and rehabilitation units. Pressure injury prevalence (all stages/categories) was 12.7%, and the incidence of hospital‐acquired pressure injuries was 10%. Of the participants, 2.6% had at least one pressure injury at admission. The risk of hospital‐acquired pressure injuries was increased for medical patients with a higher age, the inability to move independently, mode of arrival, being underweight, and the absence of a skin assessment or pressure injury risk assessment at admission. For surgical patients, the risk was associated with the inability to move independently, mode of arrival, and lack of skin assessment at admission, while being overweight protected the patients. Overall, medical patients were in greater risk of hospital‐acquired pressure injuries than the surgical patients. An assessment of the pressure injury risk and skin status should be carried out more systematically in Finnish acute care hospitals.  相似文献   
20.
Background: Chronic pain is associated with depression. Self‐treatment of depression with herbal over‐the‐counter medicine St John's wort makes pain patients prone to drug interactions. Aims: The aim of this study was to assess the potential of St John's wort to alter the CYP3A‐mediated metabolism of a μ‐opioid receptor agonist, oxycodone. Methods: The study design was placebo‐controlled, randomized, cross‐over with two phases at intervals of 4 weeks and was conducted with 12 healthy participants. St John's wort (Jarsin®) or placebo was administered t.i.d. for 15 days and oral oxycodone hydrochloride 15 mg on day 14. Oxycodone pharmacokinetics and pharmacodynamics were compared after St John's wort or placebo. Behavioural and analgesic effects were assessed with subjective visual analogue scales and cold pressor test. Plasma drug concentrations were measured from 0 to 48 h, behavioural and analgesic effects from 0 to 12 h. Results: Following St John's wort administration the oxycodone AUC decreased 50% (p < 0.001). Oxycodone elimination half‐life shortened from a mean ± SD 3.8 ± 0.7 to 3.0 ± 0.4 h (p < 0.001). The self‐reported drug effect of oxycodone as measured by AUEC0–12 decreased significantly (p = 0.004). Differences between St John's wort and placebo phases in cold pain threshold and intensity AUEC0–12 were not observed. Conclusions: St John's wort greatly reduced the plasma concentrations of oral oxycodone. The self‐reported drug effect of oxycodone decreased significantly. This interaction may potentially be of some clinical significance when treating patients with chronic pain.  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