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   32817篇
  免费   2918篇
  国内免费   37篇
耳鼻咽喉   241篇
儿科学   1110篇
妇产科学   1021篇
基础医学   4413篇
口腔科学   434篇
临床医学   4237篇
内科学   6409篇
皮肤病学   364篇
神经病学   2743篇
特种医学   821篇
外科学   3902篇
综合类   727篇
一般理论   59篇
预防医学   4284篇
眼科学   470篇
药学   2323篇
中国医学   30篇
肿瘤学   2184篇
  2023年   191篇
  2022年   261篇
  2021年   641篇
  2020年   414篇
  2019年   668篇
  2018年   723篇
  2017年   567篇
  2016年   568篇
  2015年   658篇
  2014年   903篇
  2013年   1385篇
  2012年   2004篇
  2011年   2084篇
  2010年   1089篇
  2009年   1027篇
  2008年   1681篇
  2007年   1887篇
  2006年   1753篇
  2005年   1804篇
  2004年   1599篇
  2003年   1560篇
  2002年   1398篇
  2001年   694篇
  2000年   691篇
  1999年   653篇
  1998年   391篇
  1997年   316篇
  1996年   314篇
  1995年   303篇
  1994年   245篇
  1993年   229篇
  1992年   479篇
  1991年   512篇
  1990年   481篇
  1989年   435篇
  1988年   387篇
  1987年   414篇
  1986年   378篇
  1985年   359篇
  1984年   323篇
  1983年   267篇
  1982年   190篇
  1981年   182篇
  1980年   138篇
  1979年   208篇
  1978年   162篇
  1977年   158篇
  1976年   140篇
  1974年   191篇
  1973年   168篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
To better understand the impact of incident Parkinson's disease (PD) on the Veteran's Health Administration (VHA) and to develop methods applicable to future epidemiological research, we performed a medical record review study at a tertiary referral VHA medical center. Searching the local data base, we identified 782 veterans with diagnostic codes for PD or secondary parkinsonism (SP) between 1998 and 2000. Based on structured medical record review, a movement disorders specialist confirmed diagnoses for incident parkinsonism cases. Among the 782, 191 incident parkinsonism cases were identified (100 PD, 75 SP, and 16 Parkinson's Plus). Incident PD cases were older at diagnosis (74.5 vs. 70.4 yr; P < 0.05) and more likely to be white (81% vs. 62; P < 0.07) than incident SP cases. Diagnostic codes were insufficient to distinguish between incident PD and SP (positive predictive value, 57% and 39%, respectively), and VHA sources failed to identify 21% of confirmed deaths among the incident PD cohort by November 2004. Although the large number of incident cases identified suggests PD is an important cause of disability among elderly VHA users, observed limitations of VHA sources for identifying incident PD cases and determining their vital status should be considered when designing future studies.  相似文献   
62.
Salivary disease in childhood is uncommon. Clinical features are much the same as in adult disease, however, congenital, inflammation, and functional disease is more common. Management is governed by the same general principles in all age groups. Congenital abnormalities are rare. Inflammation, either bacterial or viral, is the most common disease. Chronic sialadenitis usually resolves at puberty. Neoplasia is rare, and the majority of tumors are benign and occur in the parotid gland. Malignancy is suggested by rapid growth, pain, skin fixation, and lymphadenopathy. Surgical treatment of sialorrhea should only be considered after careful assessment. Relocation of the submandibular ducts is the treatment of choice.  相似文献   
63.
The effects of exercise training and dietary chromium intake on rat liver and muscle glycogen metabolism, tissue and body weight and feed consumption were examined. After 16 wk of training, liver, gastrocnemius and biceps femoris glycogen concentrations were higher in the trained compared to sedentary groups, independent of dietary chromium. There was a chromium x training interaction on glycogen synthase activities in the liver and gastrocnemius muscle. Liver glycogen phosphorylase activities (expressed per g liver) were lower in the chromium-supplemented rats as compared to the non-supplemented rats after 5 wk of dietary treatment, but were similar after 8 wk and higher after 18 wk. Gastrocnemius phosphorylase activity (expressed per mg protein) was lower in the trained rats as compared to the sedentary rats after 16 wk, independent of dietary chromium. Biceps femoris phosphorylase activities were not altered due to training or dietary chromium. Total protein concentration increased in the liver but decreased in the gastrocnemius due to dietary chromium. In summary, liver glycogen synthase and phosphorylase activities were dependent upon dietary chromium. Dietary chromium altered gastrocnemius synthase, but not phosphorylase activities. Changes in enzyme activities may be related to the chromium-dependent effects on liver protein and the chromium and training-dependent effects on gastrocnemius total protein.  相似文献   
64.
65.
66.
We present a case of rapid failure of a total hip arthroplasty caused by infection with Haemophilus parainfluenzae. The septic loosening occurred over a period of 3 months and followed a dental extraction that had not been covered by prophylactic antibiotics. This failure occurred in a previously well-functioning and asymptomatic prosthetic joint.  相似文献   
67.
Public knowledge about AIDS increasing   总被引:4,自引:0,他引:4  
In response to concern over the perceived limited effectiveness of Department of Health and Social Security (UK) advertising campaigns to inform the public of the basic facts of Acquired Immunodeficiency Syndrome (AIDS), a prospective questionnaire study was undertaken in Southampton, England to test the effectiveness of government education prior to a January, 1987 government television/leaflet advertising campaign. 300 questionnaires about AIDS were mailed in December of 1986 to a sample drawn from electoral rolls. The response rate was 61%. Most of the questions were drawn from material covered in the campaign. The results seemed to indicate a small overall increase in knowledge about AIDS. Some changes from a June survey were noted, e.g.: more people were aware that AIDS is a virus for which there is no cure and that it is not readily transmitted by sharing washing, eating or drinking utensils; more people believed that the statement that women are at greater risk for catching AIDS is false. Respondents were generally favorable to the government's continued use of television, even with explicit language, and to its use of the schools, for AIDS education. Many were not aware of the dangers to intravenous drug users or of the symptoms of AIDS. Other surveys have shown an increasing knowledge of AIDS dangers. It is possible that television coverage of the problem will continue to be necessary, in order that less literate populations be reached. Further AIDS health education in general is needed.  相似文献   
68.
Sensory and motor task performance was assessed at 3 to 4 month intervals in chronically underfed and ad libitum-fed control rats from maturity into senescence. Diet-restricted rats weighed less than controls and lived significantly longer. Diminished body mass improved the underfed rats' abilities to hang suspended from a wire, to maintain balance on a narrow beam, and to descend from a wire mesh pole in a coordinated fashion. Underfed rats, however, lost these abilities at the same rate as did control rats. Undernutrition did not affect the startle response to acoustic stimulation, nor did it influence auditory or visual lead stimulus inhibition of the startle response. Both groups of animals showed progressive, age-related losses of sensory-motor function which proceeded at the same rate in each group. Life-prolonging undernutrition did not appear to retard aging of these simple, reflexive behaviors.  相似文献   
69.
One hundred patients who presented to the accident and emergency (A&E) department with an acute ankle sprain were entered into a study to determine the efficacy of topical ibuprofen cream by using a double-blind placebo controlled design in a single type of soft-tissue injury. The subjects were given either topical ibuprofen cream or a placebo cream in addition to the standard management of the department. Patients kept diaries recording walking ability and pain visual analogue scales for resting, standing and walking. A total of 51 patients returned diaries that were suitable for analysis. Patients using the topical ibuprofen cream had significant reduction in pain scores over the first 48 h of treatment.  相似文献   
70.
Even though continued smoking by cancer patients adversely affects survival and quality of life, about one third of patients who smoked prior to their diagnosis continue to smoke after their diagnosis. The implementation of smoking cessation treatments for cancer patients has been slowed by the lack of data on correlates of tobacco use in this population. Thus, this longitudinal study assessed demographic, medical, addiction, and psychological predictors of tobacco use among 74 head, neck, and lung cancer patients. Multivariable binary logistic regression analyses, with outcome categorized as smoker or nonsmoker, indicated that the likelihoodthat patients would be a smoker was associated with lower levels of perceived risk and a higher level of quitting cons. Multivariable nominal logistic regression, with outcome classified as continuous smoker, continuous quitter, relapser, or follow-up quitter, indicated that: (a) patients categorized as continuous smokers reported significantly lower quitting self-efficacy than follow-up quitters and continuous quitters, (b) relapsers reported a significantly lower level of quitting self-efficacy than either follow-up quitters or continuous quitters, and (c) continuous smokers exhibited a significantly lower level of risk perceptions than continuous abstainers. These findings can be useful for the development and evaluation of treatments to promote smoking cessation among cancer patients. Support for this study was provided by National Institutes of Health Grants CA57708, CA06927, CA88610, CA95678, and CA76644.  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