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   1855857篇
  免费   124519篇
  国内免费   3782篇
耳鼻咽喉   22782篇
儿科学   61584篇
妇产科学   48913篇
基础医学   256263篇
口腔科学   50163篇
临床医学   162472篇
内科学   361544篇
皮肤病学   39277篇
神经病学   146226篇
特种医学   72217篇
外国民族医学   242篇
外科学   283760篇
综合类   41173篇
现状与发展   4篇
一般理论   531篇
预防医学   140744篇
眼科学   42770篇
药学   132261篇
  7篇
中国医学   5100篇
肿瘤学   116125篇
  2021年   12805篇
  2019年   13542篇
  2018年   40051篇
  2017年   31038篇
  2016年   34407篇
  2015年   19789篇
  2014年   26900篇
  2013年   38588篇
  2012年   58988篇
  2011年   74709篇
  2010年   49945篇
  2009年   41248篇
  2008年   69416篇
  2007年   74722篇
  2006年   55690篇
  2005年   54462篇
  2004年   53869篇
  2003年   52161篇
  2002年   48656篇
  2001年   92044篇
  2000年   94011篇
  1999年   77114篇
  1998年   19905篇
  1997年   17460篇
  1996年   17453篇
  1995年   16837篇
  1994年   15381篇
  1993年   14126篇
  1992年   57425篇
  1991年   55358篇
  1990年   53091篇
  1989年   50827篇
  1988年   46197篇
  1987年   44975篇
  1986年   42254篇
  1985年   40016篇
  1984年   29378篇
  1983年   24939篇
  1982年   13926篇
  1979年   25539篇
  1978年   17587篇
  1977年   14910篇
  1976年   13883篇
  1975年   14572篇
  1974年   17654篇
  1973年   16946篇
  1972年   15678篇
  1971年   14459篇
  1970年   13454篇
  1969年   12540篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
Abstract –  The aim of this study was to investigate mechano-sensory responses of injured and uninjured incisor teeth. Twenty-five children who had experienced dental trauma, together with age- and gender-matched controls, were studied prospectively. Touch thresholds of incisor teeth from both groups were determined using calibrated sets of von Frey hairs (force range 0.5–10.0 g in 0.5 g increments) using a forced choice staircase method. Forces were applied perpendicular to the buccal enamel surfaces along the midline, 2 mm from the incisal edge. Touch threshold was defined as the lowest force detected in three out of the five occasions. Following statistical analysis, P  < 0.05 was considered significant. At initial examination, the touch threshold values of 25 traumatised teeth were significantly greater than the untraumatised controls ( P  < 0.001), and these values approached those of the control teeth over 3–12 months ( P  > 0.05). Dental trauma was associated with increased touch thresholds in permanent incisor teeth, with recovery toward healthy control values usually occurring between 3–12 months.  相似文献   
82.
The finer branches of the biliary tree (FBBT) contain a regenerative compartment. We hypothesized that preservation of the FBBT together with its microvasculature will lead to recovery of biliary damage and prolonged preservation of bile ductules during the development of chronic liver allograft rejection. The interlobular bile ducts, portal bile ductules and extraportal biliary cells with and without microvessels were studied in sequential biopsies in five patients who fulfilled the Banff criteria of early chronic rejection (CR) (imminence group). Biopsies of CR patients (n = 12) served as controls. Biopsies were double immunostained with CD34 (microvessels) and cytokeratin 7 (biliary structures). Proliferation and proangiogenic activity were assessed with Ki67 and VEGF-A immunostaining. Severe damage of bile ducts in the imminence group did not progress to significant bile duct loss. This was associated with a high proliferative activity in all biliary structures and preservation of the microvascular compartment. VEGF-A expression was increased in all but the reperfusion biopsies. In conclusion, both regenerative activity of the FBBT and an intact microvascular compartment are associated with less damage of the biliary tree and could therefore be prerequisites for biliary regeneration.  相似文献   
83.
The reliable change index (RCI) expresses change relative to its associated error, and is useful in the identification of post-operative cognitive dysfunction (POCD). This paper examines four common RCIs that each account for error in different ways. Three rules incorporate a constant correction for practice effects and are contrasted with the standard RCI that had no correction for practice. These rules are applied to 160 patients undergoing coronary artery bypass graft (CABG) surgery who completed neuropsychological assessments preoperatively and 1 week post-operatively using error and reliability data from a comparable healthy non-surgical control group. The rules all identify POCD in a similar proportion of patients, but the use of the within subject standard deviation, expressing the effects of random error, as an error estimate is a theoretically appropriate denominator when a constant error correction, removing the effects of systematic error, is deducted from the numerator in a RCI.  相似文献   
84.
85.
BACKGROUND: We prospectively evaluated the usefulness of IgA tissue transglutaminase antibodies (IgA tTG) in the initial diagnosis of celiac disease (CD) and compared its diagnostic potential with that of IgA anti-endomysial antibodies (IgA EMA) and anti-IgA and IgG gliadin antibodies (AGA and AGG, respectively). METHODS: Sera of 23 untreated children fulfilling the revised ESPGHAN criteria for diagnosis of CD (Group I; mean age 10.8 y); 19 disease controls (Group II; mean age 8.5 y) presenting with chronic diarrhea, short stature or both; and 22 healthy children (Group III; mean age 8.8 y) were studied. These were tested in a blinded manner for AGA, AGG, IgA tTG (guinea pig as antigen) and IgA EMA. RESULTS: In Group I, IgA EMA was positive in 19, IgA tTG in 17, AGA in 14 and AGG in 17 patients. In Group II, these tests were positive in 1, 0, 2 and 14 patients, respectively and in Group III, in 0, 0, 0 and 1 child, respectively. Analyzing data from Group I and II, IgA EMA, IgA tTG, AGA and AGG had sensitivity rates of 83%, 74%, 61% and 74%, respectively; the specificity rates were 95%, 100%, 89% and 26%; positive predictive values were 95%, 100%, 88% and 55% and negative predictive values were 82%, 74%, 65% and 45%, respectively. CONCLUSION: IgA tTG is useful for the diagnosis of CD, with sensitivity and specificity rates comparable to those of EMA and this test is well suited for use in tropical countries like India.  相似文献   
86.
87.
Relationship-centered care reflects both knowing and feeling: the knowledge that physician and patient bring from their respective domains of expertise, and the physician’s and patient’s experience, expression, and perception of emotions during the medical encounter. These processes are conveyed and reciprocated in the care process through verbal and nonverbal communication. We suggest that the emotional context of care is especially related to nonverbal communication and that emotion-related communication skills, including sending and receiving nonverbal messages and emotional self-awareness, are critical elements of high-quality care. Although nonverbal behavior has received far less study than other care processes, the current review argues that it holds significance for the therapeutic relationship and influences important outcomes including satisfaction, adherence, and clinical outcomes of care.  相似文献   
88.
89.
90.
OBJECTIVES: Pseudotumour cerebri has been previously recognized as a neurological side effect of combined oral contraceptives but has not been diagnosed with a delay of 3 years after initiation of combined oral contraceptives. CASE REPORT: A 19-year-old obese woman developed visual impairment and headache, 4 months after starting combined oral contraceptives. Three years later symptoms deteriorated and she presented with prominent tendon-jerks and congested optical-discs. Normal CSF drained with high pressure from the spinal tap. Pseudotumour cerebri was diagnosed. Headache and visual impairment resolved within 3 weeks after discontinuation of combined oral contraceptives. CONCLUSIONS: Combined oral contraceptives-induced pseudotumour cerebri may remain undetected for years. Young, obese women with visual impairment and headache under combined oral contraceptives should undergo immediate neurological and ophthalmological investigation.  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