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   7685篇
  免费   688篇
  国内免费   14篇
耳鼻咽喉   59篇
儿科学   238篇
妇产科学   106篇
基础医学   895篇
口腔科学   164篇
临床医学   866篇
内科学   1517篇
皮肤病学   96篇
神经病学   444篇
特种医学   511篇
外科学   1038篇
综合类   176篇
一般理论   1篇
预防医学   873篇
眼科学   97篇
药学   603篇
中国医学   4篇
肿瘤学   699篇
  2023年   47篇
  2022年   43篇
  2021年   109篇
  2020年   72篇
  2019年   106篇
  2018年   143篇
  2017年   108篇
  2016年   132篇
  2015年   121篇
  2014年   191篇
  2013年   271篇
  2012年   365篇
  2011年   341篇
  2010年   219篇
  2009年   179篇
  2008年   330篇
  2007年   364篇
  2006年   328篇
  2005年   292篇
  2004年   299篇
  2003年   272篇
  2002年   274篇
  2001年   268篇
  2000年   284篇
  1999年   217篇
  1998年   116篇
  1997年   104篇
  1996年   95篇
  1995年   113篇
  1994年   101篇
  1993年   82篇
  1992年   188篇
  1991年   168篇
  1990年   158篇
  1989年   149篇
  1988年   185篇
  1987年   153篇
  1986年   123篇
  1985年   145篇
  1984年   104篇
  1983年   103篇
  1982年   60篇
  1981年   56篇
  1979年   94篇
  1978年   68篇
  1977年   49篇
  1976年   52篇
  1974年   55篇
  1973年   62篇
  1970年   43篇
排序方式: 共有8387条查询结果,搜索用时 15 毫秒
61.
62.
The Pittsburgh Sleep Diary   总被引:5,自引:3,他引:2  
SUMMARY  Increasingly, there is a need in both research and clinical practice to document and quantify sleep and waking behaviors in a comprehensive manner. The Pittsburgh Sleep Diary (PghSD) is an instrument with separate components to be completed at bedtime and waketime. Bedtime components relate to the events of the day preceding the sleep, waketime components to the sleep period just completed. Two-week PghSD data is presented from 234 different subjects, comprising 96 healthy young middle-aged controls, 37 older men, 44 older women, 29 young adult controls and 28 sleep disorders patients in order to demonstrate the usefulness, validity and reliability of various measures from the instrument. Comparisons are made with polysomnographic and actigraphic sleep measures, as well as personality and circadian type questionnaires. The instrument was shown to have sensitivity in detecting differences due to weekends, age, gender, personality and circadian type, and validity in agreeing with actigraphic estimates of sleep timing and quality. Over a 12–31 month delay, PghSD measures of both sleep timing and sleep quality showed correlations between 0.56 and 0.81 ( n = 39, P < 0.001).  相似文献   
63.
Demyelination of axons within the spinal cord represents a significant component of the pathology of contusive and compressive spinal cord injury (SCI) and the associated conduction deficits most probably contribute to the paralysis and sensory loss experienced by SCI patients. 4-Aminopyridine (4-AP) is a potassium (K+) channel blocking agent that has been shown capable of restoring conduction across demyelinated internodes in neurons of the spinal cord. Recent clinical trials of 4-AP provide evidence that limited and transient neurological gain may be derived by some SCI patients with longstanding injury. The present review traces the historical development of 4-AP, describes the mechanism of action and rationale for use in SCI, and provides an overview of the clinical trials conducted to date. The early trials give rise to optimism that pharmaceutical management of conduction deficits may have a role to play in restoring neurological function in some patients with SCI.  相似文献   
64.
Bioabsorbable implants have been advocated for use in repair of a torn glenoid labrum to correct shoulder instability. These implants have been thought to be safe and to have little toxicity, antigenicity, or adverse side effects. However, similar implants have been shown to cause nonspecific granulomatous reactions when implanted into bone or soft tissues in studies in both animals and human beings. This article reports the adverse effects of these implants in six shoulders of five patients who had repair of a damaged glenoid labrum. All patients reported increasing pain and loss of shoulder motion after insertion of these devices. All required a further arthroscopic lavage and debridement to reduce the inlracapsular synovitis. Granulomatous reactions were identified histologically in all cases. No long-term side effects were encountered, and all patients recovered satisfactorily.  相似文献   
65.
In view of the economic constraints in acquiring sophisticated equipments in service hospitals, a new suspension device for endolaryngeal surgery using anaesthetic laryngoscope and routinely available tonsillectomy instruments has been developed. This device is a modification of Ijadoula''s suspension laryngoscope.KEY WORDS: Suspension laryngoscope, Laryngeal endoscopy  相似文献   
66.
67.
BACKGROUND: Vitamin A supplementation is being used successfully to treat some forms of cancer and the degenerative eye disease retinitis pigmentosa. The daily biological need for vitamin A is estimated to be 800 retinol equivalents (RE)/d (2667 IU/d) for adult women and 1000 RE/d (3300 IU/d) for adult men; doses > or = 7500 RE (> or = 25000 IU)/d are considered potentially toxic over the long term. OBJECTIVE: We assessed the safety in adults of long-term vitamin A supplementation with doses above the daily biological need but <7500 RE (<25000 IU)/d. DESIGN: Adults aged 18-54 y with retinitis pigmentosa but in generally good health (n = 146) were supplemented with 4500 RE (15000 IU) vitamin A/d for < or = 12 y (group A) and compared with a similar group (n = 149) that received 23 RE (75 IU)/d (trace group). Mean total consumption of vitamin A in group A was 5583 RE (18609 IU)/d (range: 4911-7296 RE/d, or 16369-24318 IU/d) and that in the trace group was 1053 RE (3511 IU)/d (range: 401-3192 RE/d, or 1338-10638 IU/d). RESULTS: Patients in group A showed an 8% increase in mean serum retinol concentration at 5 y and an 18% increase at 12 y (P < 0.001); no retinol value exceeded the upper normal limit (3.49 micromol/L, or 100 microg/dL). Mean serum retinyl esters were elevated approximately 1.7-fold at 5 y and remained relatively stable thereafter. No clinical symptoms or signs of liver toxicity attributable to vitamin A excess were detected. CONCLUSIONS: Prolonged daily consumption of <7500 RE (<25000 IU) vitamin A/d can be considered safe in this age group.  相似文献   
68.
Population health promotion illustrates most robustly that health is a shared responsibility. Improving our understanding of the social production of health and the purchase population health promotion has on shaping social welfare policy presents a number of challenges to the future development of this discourse. Three are briefly discussed in this paper. First is the matter of language we use to describe our understanding of processes and influences. Second is the conceptualization of the pathways that shape population health status. Finally, cultural practices both extant and required to improve health status and reduce inequalities are addressed.  相似文献   
69.
70.
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