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   21125篇
  免费   1832篇
  国内免费   31篇
耳鼻咽喉   235篇
儿科学   629篇
妇产科学   506篇
基础医学   2642篇
口腔科学   469篇
临床医学   2460篇
内科学   3697篇
皮肤病学   226篇
神经病学   2110篇
特种医学   534篇
外科学   2708篇
综合类   580篇
一般理论   25篇
预防医学   2302篇
眼科学   535篇
药学   1619篇
中国医学   18篇
肿瘤学   1693篇
  2023年   122篇
  2022年   179篇
  2021年   343篇
  2020年   249篇
  2019年   342篇
  2018年   387篇
  2017年   301篇
  2016年   348篇
  2015年   387篇
  2014年   498篇
  2013年   767篇
  2012年   1113篇
  2011年   1078篇
  2010年   607篇
  2009年   546篇
  2008年   977篇
  2007年   1044篇
  2006年   938篇
  2005年   948篇
  2004年   922篇
  2003年   836篇
  2002年   861篇
  2001年   627篇
  2000年   577篇
  1999年   516篇
  1998年   263篇
  1997年   203篇
  1996年   219篇
  1995年   208篇
  1994年   188篇
  1993年   182篇
  1992年   393篇
  1991年   389篇
  1990年   418篇
  1989年   377篇
  1988年   368篇
  1987年   353篇
  1986年   345篇
  1985年   301篇
  1984年   241篇
  1983年   195篇
  1982年   136篇
  1981年   122篇
  1979年   235篇
  1978年   157篇
  1977年   133篇
  1976年   122篇
  1975年   144篇
  1974年   164篇
  1973年   131篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
21.
22.
Poverty influences health status, life expectancy, health behaviours, and use of health services. This study examined factors influencing the use of health-related services by people living in poverty. In the first phase, 199 impoverished users of health-related services in 2 large Canadian cities were interviewed by their peers. In the second phase, group interviews with people living in poverty (n = 52) were conducted. Data were analyzed using thematic content analysis. Diverse health-related services were used to meet basic and health needs, to maintain human contact, and to cope with life's challenges. Use of services depended on proximity, affordability, convenience, information, and providers' attitudes and behaviours. Use was impeded by inequities based on income status. To promote the health of people living in poverty, nurses and other health professionals can enhance the accessibility and quality of services, improve their interactions with people living in poverty, provide information about available programs, offer coordinated community-based services, collaborate with other sectors, and advocate for more equitable services and policies.  相似文献   
23.
24.
Corneal thickness measurements and endothelial cell counts were carried out in 34 patients undergoing treatment for glaucoma with 4% pilocarpine gel between 18 to 78 months after initiation of therapy. The corneal thickness and endothelial cell population were found to be within normal limits in all cases except two, one patient with increased corneal thickness who had recently undergone cataract and glaucoma filtering surgery and another patient with decreased cell count who had an old endothelial scar sustained prior to pilocarpine gel therapy. There was a very close correlation for both of these parameters noticed in patients treated with pilocarpine gel and in age-matched control group of patients with glaucoma. The present study has shown that there are no adverse corneal effects with pilocarpine gel therapy.  相似文献   
25.
26.
This paper reports the results of a survey in which pregnant women in London and Edinburgh were asked about their knowledge and understanding of the recent recommendations of expert committees (James, 1983; DHSS, 1984). In general, Londoners had a better understanding, although in both regions manual groups were less knowledgeable, with the Edinburgh manual group the least well informed.  相似文献   
27.
1. The kidney bean lectin, phytohaemagglutinin (PHA), induced a marked atrophy of skeletal muscle which was evident from the changes in tissue composition (protein, RNA, DNA and polyamine content) and from the reduction in weight and protein synthesis of hind leg muscles of rats fed on kidney bean-diets for four days. The beta-adrenoceptor agonist, clenbuterol, induced skeletal muscle hypertrophy by transiently stimulating protein synthesis. As a consequence, the muscle loss caused by a short exposure to PHA was, in part, ameliorated by clenbuterol treatment. 2. Cardiac muscle was affected to a lesser extent than skeletal muscle by both clenbuterol and the lectin. However, there was evidence that protein synthesis in heart was reduced by PHA. 3. PHA had opposite effects on the gut, the lectin-induced hyperplasia of the jejunum was accompanied by a large increase in protein synthesis. Clenbuterol alone had no effect on the jejunum whereas a combination of PHA and clenbuterol appeared to exacerbate the effect of the lectin on gut. 4. Both the lectin-induced gut growth and the hypertrophy of skeletal muscle caused by clenbuterol were preceded by the accumulation of polyamines in the respective tissues. Of particular note was the observation that a significant increase in the proportion of the intraperitoneally injected 14C-labelled spermidine or putrescine taken up by the growing tissues could be detected by the second day. Therefore, the measurement of uptake of labelled polyamines may be used as a sensitive indicator of early alterations in tissue metabolism.  相似文献   
28.
OBJECTIVE: This study prospectively evaluates the effectiveness and patient acceptability of professionally-led support groups in alleviating psychologic distress in infertility patients. METHOD: Sixty-four consecutive patients in a university hospital infertility program were administered a battery of psychologic tests before and after attendance at an 8 weekly session support group. The comparison group consisted of 35 consecutive infertility referrals to the same unit who were not initially offered the support group and were similarly tested over an 8 week period. RESULTS: Support group patients had significantly greater (p less than or equal to 0.01) entry than exit scores on several measures of psychologic distress and depression (the Beck Depression Inventory, the Hamilton Rating Scale for Depression, and the Global Severity Index, Anxiety, Depression, Hostility and Obsessive Compulsive Subscales of the Brief Symptom Inventory). The Avoidance Coping Style on the Moos Coping Responses Inventory was correlated with a higher Global Severity Index (p less than or equal to 0.01). Comparison group patients had similar psychometric scores to the support group patients at entry but showed no change over 8 weeks. Attenders expressed a high rate of satisfaction with the support group. CONCLUSIONS: Professionally-led support groups are a highly acceptable and effective intervention in self-referred patients in alleviating psychological distress related to infertility.  相似文献   
29.
D Stewart  R B Leman  J Kaiser  D L Mann 《Chest》1991,99(3):651-655
The incidence and severity of catheter-induced tricuspid regurgitation has not been studied extensively. Given the frequency with which right heart catheters are employed to measure cardiac output, it is important to know whether the severity of catheter-induced tricuspid regurgitation is sufficient to invalidate the measurement of thermodilution cardiac output. Accordingly, the purpose of the present prospective study was to determine the incidence and severity of catheter-induced tricuspid regurgitation in 25 men (mean age, 58.1 +/- 1.4 years) using Doppler ultrasound. The tricuspid valve was interrogated from two orthogonal views using pulsed-wave and color flow Doppler, either in the presence or absence of a 7-French catheter across the tricuspid valve. The severity of catheter-induced tricuspid regurgitation was graded semiquantitatively using a validated scoring system. Pulsed-wave Doppler studies showed that the incidence of catheter-induced tricuspid regurgitation was 48 percent, and that the average tricuspid regurgitation score increased from 0.41 +/- 0.16 to 0.61 +/- 0.17 (p less than 0.01). Color flow Doppler studies showed similar findings. Further, the incidence of catheter-induced tricuspid regurgitation was not related to the patient's underlying hemodynamic status or right ventricular geometry. In conclusion, this study shows for the first time that the quantitative extent of catheter-induced tricuspid regurgitation is small, and is therefore unlikely to be important clinically, particularly with regard to the assessment of thermodilution cardiac output.  相似文献   
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