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   18774篇
  免费   1679篇
  国内免费   52篇
耳鼻咽喉   165篇
儿科学   652篇
妇产科学   288篇
基础医学   2390篇
口腔科学   515篇
临床医学   2124篇
内科学   3835篇
皮肤病学   196篇
神经病学   1635篇
特种医学   608篇
外科学   2924篇
综合类   469篇
一般理论   37篇
预防医学   1592篇
眼科学   333篇
药学   1522篇
中国医学   7篇
肿瘤学   1213篇
  2023年   103篇
  2022年   144篇
  2021年   357篇
  2020年   215篇
  2019年   353篇
  2018年   432篇
  2017年   287篇
  2016年   308篇
  2015年   320篇
  2014年   569篇
  2013年   744篇
  2012年   1038篇
  2011年   1109篇
  2010年   603篇
  2009年   597篇
  2008年   997篇
  2007年   1024篇
  2006年   965篇
  2005年   1040篇
  2004年   936篇
  2003年   868篇
  2002年   782篇
  2001年   478篇
  2000年   417篇
  1999年   402篇
  1998年   222篇
  1997年   162篇
  1996年   162篇
  1995年   149篇
  1994年   135篇
  1993年   140篇
  1992年   324篇
  1991年   288篇
  1990年   293篇
  1989年   273篇
  1988年   258篇
  1987年   265篇
  1986年   257篇
  1985年   248篇
  1984年   199篇
  1983年   171篇
  1982年   151篇
  1981年   127篇
  1980年   99篇
  1979年   127篇
  1978年   96篇
  1976年   109篇
  1974年   103篇
  1973年   121篇
  1972年   99篇
排序方式: 共有10000条查询结果,搜索用时 46 毫秒
11.
1. The present study aimed to determine the feasibility of conducting a 5 year cardiovascular outcome trial of the treatment of 6000 elderly hypertensive patients in Australian general practices. 2. General practitioners (GPs) were invited to participate by mail and personal follow-up. Patient records were reviewed to identify subjects for a blood pressure (BP) screening programme. Blood pressure was measured on three occasions and eligible subjects were included if the average BP was 160 mmHg systolic or 90 mmHg diastolic if systolic BP was 140 mmHg. 3. Seven hundred and forty-one GPs were approached and 89 were enrolled in the study (12% of mail invites and 75% of those receiving a personal contact). In 16 practices where screening was completed, 82 000 records were reviewed to identify 4% patients eligible for screening. Twenty-two per cent of eligible subjects attended screening. Of 1938 subjects screened, 180 (9%) had BP 5=160/90 mmHg. Forty-seven percent of subjects (n = 916) were receiving antihypertensive therapy and 184 (20%) were withdrawn from therapy. One hundred and sixteen (63%) of these subjects had BP return to study entry levels within 6 weeks. Fifty-seven newly diagnosed and 81 previously treated subjects were randomized (7% of the screened population). 4. Based on the high participation rate of GPs, the response rate of patients to attend a BP screening programme and the 7% randomization to screening ratio for entry into the study, the ANBP2 pilot study has demonstrated that it is feasible to recruit subjects from Australian general practices to a cardiovascular outcome trial.  相似文献   
12.
13.
A visual word identification task was used to measure the type of selective attention that occurs spontaneously when there are multiple stimuli, all potentially relevant, and insufficient time to process each of them fully. This task presents two words simultaneously, one above the other, for 200 ms, and periodically requires the subject to identify either the upper or the lower word. We tested schizophrenic patients, manic-depressive patients, and normal controls under a baseline divided attention condition with no predictability and then introduced a degree of predictability into the upper location that normally results in selective attention to the lower nonpredictable location. In both the divided attention and the selective attention conditions, the schizophrenic group was just as accurate in identifying words as the other two groups, indicating no deficit in the rate of information processing. However, spontaneous selective attention under conditions of predictability was abnormal in the schizophrenic patients: They paid more attention to the predictable than to the nonpredictable source of information, consequently processing different, not less, information than normal subjects. Abnormal values on a ratio measure of selective attention occurred in 85% of the schizophrenic patients compared with only 30% of the manic-depressives and 20% of the normal subjects.  相似文献   
14.
The purpose of this investigation was to determine the site utilized by nurses for administering Diphtheria and Tetanus Toxoids and Pertussis (DPT) injections to infants under 7 months of age. Twenty-six of the 28 agencies identified in a metropolitan area as administering DPT injections chose to participate in the study. Those individuals administering DPT injections in the agencies completed a questionnaire with a return rate of 69% (n = 55). Forty-four participants indicated that they used the anterolateral thigh, the recommended site, 100% of the time. The participants in the study administered a total of 1,453 DPT injections per month. Eighty-seven percent of those injections were administered in the anterolateral thigh, 3.6% were given in the deltoid, 5.1% were given in the dorsal gluteal, and 4% were given in the ventrogluteal. The estimated proportion of DPT injections administered at the correct site was 84.65% which is much lower than the critical value 94.06% for alpha = .05 (p less than .00001).  相似文献   
15.
16.
17.
Fasting plasma proinsulin, insulin and glucose concentrations were measured in ten women with mild gestational diabetes and ten controls matched for race, age (32 +/- 6 vs 31 +/- 6 years), body mass index (28 +/- 8 vs 27 +/- 6) and gestational week (24 +/- 4 vs 25 +/- 4 weeks). There was no significant difference in fasting plasma glucose between these gestational diabetics and their controls (median 4.7, range 3.7-6.0 mmol/l vs 4.5, range 3.4-5.3 mmol/l). The fasting proinsulin levels were significantly higher in the gestational diabetics compared with the controls (median 12.2, range less than 4-14.8 pmol/l vs 5.8, range less than 4-12.8 pmol/l, P less than or equal to 0.02, Wilcoxon Summed Rank Test), while the calculated intact insulin levels (immunoreactive insulin minus proinsulin) were significantly lower (median 14.5, range 6.3-81.8 pmol/l vs 51.6, range 11.7-312 pmol/l, P less than or equal to 0.01). The ratio of proinsulin to calculated intact insulin was significantly higher in the gestational diabetics than the controls (median 0.66, range 0.16-2.04 vs 0.12, range 0.03-0.62), P less than or equal to 0.01). These results demonstrate that gestational diabetics, with normal fasting plasma glucose values, have abnormalities in pancreatic beta-cell secretion, which are likely to be important both in the aetiology of gestational diabetes and non-insulin dependent diabetes.  相似文献   
18.
19.
20.
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