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   706篇
  免费   41篇
  国内免费   12篇
耳鼻咽喉   14篇
儿科学   53篇
妇产科学   11篇
基础医学   98篇
口腔科学   6篇
临床医学   61篇
内科学   123篇
皮肤病学   10篇
神经病学   50篇
特种医学   18篇
外科学   155篇
综合类   5篇
预防医学   22篇
眼科学   17篇
药学   49篇
中国医学   5篇
肿瘤学   62篇
  2023年   5篇
  2021年   11篇
  2018年   10篇
  2017年   11篇
  2016年   9篇
  2015年   9篇
  2014年   17篇
  2013年   24篇
  2012年   34篇
  2011年   40篇
  2010年   30篇
  2009年   31篇
  2008年   44篇
  2007年   41篇
  2006年   39篇
  2005年   55篇
  2004年   35篇
  2003年   20篇
  2002年   46篇
  2001年   26篇
  2000年   27篇
  1999年   20篇
  1998年   10篇
  1997年   6篇
  1996年   5篇
  1995年   3篇
  1994年   4篇
  1993年   5篇
  1992年   8篇
  1991年   8篇
  1990年   10篇
  1989年   10篇
  1988年   10篇
  1987年   8篇
  1986年   9篇
  1985年   6篇
  1984年   7篇
  1982年   3篇
  1979年   6篇
  1978年   3篇
  1977年   3篇
  1976年   4篇
  1975年   2篇
  1973年   5篇
  1972年   2篇
  1971年   3篇
  1970年   3篇
  1969年   2篇
  1964年   2篇
  1936年   2篇
排序方式: 共有759条查询结果,搜索用时 46 毫秒
1.
Polyploidization and centrosome hyperamplification in inflammatory bronchi   总被引:1,自引:0,他引:1  
OBJECTIVE AND DESIGN: Inflammatory and tumorous bronchi were screened in order to obtain new tumor relevant cytogenetic parameters. MATERIAL OR SUBJECTS: Bronchial cells of 32 patients were cultivated by standard cell culture procedures. METHODS: Tetraploidy and aneuploidy was determined by enumeration of chromosome 7 and 8 versus the number of centrosomes. The resulting data were correlated with histopathological data. RESULTS: Tetra- and aneuploidy of epithelial cells were detectable in 76% of tumor cell cultures, 75% of high grade inflammatory tissues and 40% of non- and low grade-inflammatory tissues. Additionally, we observed centrosome hyper-amplification and multipolar mitoses not only in the tumor but also in the early stages of inflammation. CONCLUSION: Inflammatory bronchi already show tumor-specific features and may consequently represent the preliminary genetic stage of cancer development in bronchi.  相似文献   
2.
FIRST DIAGNOSIS OF SEVERE HANDICAP: A STUDY OF PARENTAL REACTIONS   总被引:2,自引:2,他引:0  
This paper reports the results of interviews with 190 parents of severely mentally handicapped children. Questions were asked about parents' satisfaction with the way they were first informed of the child's impairment. Most parents were informed by a doctor, and almost two-thirds were dissatisfied with the first information given. Satisfaction was associated with being told early in the child's life. There was a significant association between the time of telling and the diagnostic condition of the child: parents of children with handicap of no known pathology were more likely to be told during or after the second year of the child's life, while parents of children with Down's syndrome were most likely to be told at birth. The authors discuss ways in which parents can be helped through this difficult time and suggest procedures for breaking the news to parents in a sensitive way.  相似文献   
3.
A necropsy study of the pathological findings in the digestive system of 19 renal transplant recipients revealed that gastrointestinal (GI), hepatobiliary, and pancreatic pathologies are common in renal transplant recipients. Fifteen of the 19 patients studied had GI pathology. Hepatobiliary pathology was the most common finding with all but one of the 19 cases exhibiting one or more abnormalities. Pancreatic abnormalities were less frequent with 11 patients demonstrating normal findings.  相似文献   
4.
The present study is based on the initiative for quality assurance in pathology of the German Society of Pathology and the Professional Association of German Pathologists. Four panel laboratories with experience and expertise in polymerase chain reaction (PCR) detection of Mycobacterium tuberculosis were selected to establish the prerequisites for continuous external laboratory trials, in particular, by providing pre-tested specimens and evaluation criteria for participating institutes. In the first step, the four panel laboratories performed an internal trial to test their own reliability and reproducibility. Paraffin sections and DNA preparations from 34 tissues (25 clinical specimens and 9 controls) totalling to 66 samples were evaluated by each panel institute according to their own protocols. The methodologies differed and are described in detail. Despite these differences, a high degree of inter-laboratory reliability was achieved. In this report, we summarise our results including the correlation with the histology and provide recommendations for applying PCR-based methodology for the detection of mycobacterial DNA in surgical specimens. Supplementary data are available online at (rubric Forschung). Pre-tested specimens are now available for the external trial and can be ordered from the steering institute via Oligene (). All molecular pathology laboratories are invited to participate in this quality assurance initiative.  相似文献   
5.
 Renal cell carcinomas belong to the small group of tumors that are able to induce antitumor responses. Here we describe two general types of cytotoxic effector lymphocytes that can eliminate autologous tumor cells and discuss the role that major histocompatibility complex encoded molecules play in governing their specificities. Improved understanding of the cellular and molecular basis of renal cell carcinoma recognition opens new avenues of research with the potential to develop better immunotherapies for patients with metastatic disease. Received: 24 July 1996 / Accepted: 1 November 1996  相似文献   
6.
Summary Interrelations between age and plasma renin, aldosterone and cortisol levels, urinary catecholamines, plasma and blood volumes, exchangeable body sodium and blood pressure were studied in 28 young (19 to 29 years), 16 middle-aged (32 to 58 years) and 15 elderly (60 to 74 years) healthy subjects. Supine and upright plasma renin and supine aldosterone levels decreased while urinary noradrenaline excretion rate increased progressively with aging (r0.34;p<0.05), with significant differences in mean values between young and elderly subjects (p<0.02). There was also an age-related decrease in upright plasma aldosterone concentration, although this was not statistically significant. Furthermore, mean plasma cortisol concentrations increased in response to upright posture in elderly (+50%;p<0.02), but not in young (–10%) or middle-aged (–8%) subjects. Blood pressure correlated with age (r=0.35;p<0.05) or noradrenaline excretion rate (r=0.34) in the entire study population and with blood volume in the elderly (r=0.68), but not in the young or middle-aged study groups. There were no significant age-related differences in the body sodium/volume state, basal plasma cortisol levels or urinary adrenaline excretion rate, and plasma renin or aldosterone levels did not correlate with these parameters or with blood pressure. It is concluded that the influence of age on plasma renin or aldosterone levels, plasma cortisol responsiveness to upright posture, and urinary noradrenaline excretion should be taken into consideration, whenever these factors have to be interpreted in patients with arterial hypertension or other clinical disorders. Furthermore, these data are consistent with the possibility that in normal man increases in supine blood pressure with aging may be related at least partly to concomitant changes in free peripheral noradrenaline.This investigation was supported by the Swiss National Science Foundation  相似文献   
7.
The gradual closure of a long-stay hospital is stressful for staff. Some may have doubts about the case for community care, and almost all are affected by uncertainty and by the provisional step-by-step changes as patients gradually move out. The maintenance of staff morale during the transition is therefore important and difficult. This article examines some of the stresses and misunderstandings, and suggests how they could be managed.  相似文献   
8.
Incidence of esophageal carcinoma With more than 300 000 new cases per year, cancerof the esophagus, predominantly squamous cell carcinoma(SCC), is one of the 10 most frequently diagnosed tumortypes. Esophageal cancer occurs often in developing coun-tries and shows great regional di?erences[1]. While in re-cent history the incidence of SCC has decreased slightly inregions of high risk and stayed constant in the USA andWestern Europe, the rate of adenocarcinoma of the esoph-agus (AC) has…  相似文献   
9.
Physical activity in early midlife has important implications for women's health. The present cross-sectional study investigated the relation of purposiveness to leisure-time physical activity, as mediated by health investment, in a sample of women in early midlife. Participants were 211 women between the ages of 35 and 45 years (mean 40.55 years, SD = 3.11) who responded to the second wave of the study of Midlife Development in the United States. Participants were originally selected by means of a nationally representative random-digit-dialing procedure. A structural equation analysis of data with latent variables was conducted with MPLUS. Purposiveness was indexed by measures of purpose in life, personal growth, and future planning. Health investment was indexed by thought and effort committed to health and the extent to which individuals worked hard to stay healthy. Leisure-time physical activity was indexed by both moderate and vigorous leisure-time activity. Results, controlling for sociodemographic factors, showed that purposiveness was associated with more physical activity and that the relation between purposiveness and leisure-time physical activity was fully mediated by health investment. These results suggest that women with a sense of purpose may be better able to achieve acceptable levels of physical activity.  相似文献   
10.

Aims and objectives

This study aimed to determine the influences of gender, BMI and observed body shape on subcutaneous fat and muscle thicknesses, and theoretical injection outcome, at the ventrogluteal and dorsogluteal intramuscular injection sites.

Background

Debate continues as to whether the dorsogluteal or ventrogluteal injection site is more reliable for a successful intramuscular injection outcome. Subcutaneous fat and muscle thicknesses at the injection site are direct determinants of intramuscular injection outcome. BMI and observed body shape influence gluteal subcutaneous fat and muscle thicknesses, and therefore injection outcome, with potentially distinct effects at the ventrogluteal and dorsogluteal sites.

Design

This was a cross‐sectional study.

Methods

Demographic data were collected, and subcutaneous fat and muscle thicknesses were quantified bilaterally at the dorsogluteal and ventrogluteal injection sites using ultrasound, for 145 participants (57% female).

Results

Subcutaneous fat and muscle were significantly thicker at the dorsogluteal than the ventrogluteal site, and 75% and 86% of participants would receive a successful intramuscular injection at these sites, respectively. There were significant effects of gender, BMI and observed body shape on subcutaneous fat thickness and theoretical injection outcome at both sites. Females, obese individuals and endomorph individuals had thicker subcutaneous fat and were more likely to have a subcutaneous injection outcome.

Conclusions

Gender, BMI and observed body shape could be used to guide site and needle length selection when administering gluteal intramuscular injections to increase the likelihood of a successful intramuscular injection outcome.

Relevance to clinical practice

Both gluteal injection sites should be avoided in obese individuals and endomorph individuals. An intramuscular injection will be successful: using a 32‐mm needle at the ventrogluteal site for all males and normal‐weight females and using a 38‐mm needle for all females at the ventrogluteal site, and for all males and at least 98% of females at the dorsogluteal site.  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