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   1338718篇
  免费   114849篇
  国内免费   6371篇
耳鼻咽喉   16719篇
儿科学   43156篇
妇产科学   36655篇
基础医学   183911篇
口腔科学   36313篇
临床医学   120894篇
内科学   278991篇
皮肤病学   31962篇
神经病学   110683篇
特种医学   55673篇
外国民族医学   275篇
外科学   210709篇
综合类   31562篇
现状与发展   2篇
一般理论   414篇
预防医学   106786篇
眼科学   28149篇
药学   93854篇
  5篇
中国医学   2238篇
肿瘤学   70987篇
  2018年   13427篇
  2017年   10670篇
  2016年   12859篇
  2015年   14344篇
  2014年   20004篇
  2013年   29807篇
  2012年   36353篇
  2011年   39011篇
  2010年   24439篇
  2009年   23971篇
  2008年   36482篇
  2007年   38900篇
  2006年   40049篇
  2005年   38623篇
  2004年   36848篇
  2003年   35932篇
  2002年   33917篇
  2001年   66119篇
  2000年   67964篇
  1999年   56651篇
  1998年   16748篇
  1997年   15045篇
  1996年   16044篇
  1995年   16259篇
  1994年   15119篇
  1993年   14169篇
  1992年   47145篇
  1991年   45784篇
  1990年   44007篇
  1989年   41854篇
  1988年   38784篇
  1987年   38122篇
  1986年   35887篇
  1985年   34670篇
  1984年   26383篇
  1983年   22123篇
  1982年   13854篇
  1981年   12457篇
  1980年   11723篇
  1979年   23574篇
  1978年   17086篇
  1977年   14394篇
  1976年   13196篇
  1975年   13734篇
  1974年   16101篇
  1973年   15411篇
  1972年   14179篇
  1971年   13043篇
  1970年   11883篇
  1969年   11106篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
62.
63.
Porocarcinoma is an unusual, locally aggressive and potentially fatal neoplasm. Several cutaneous malignancies have been described in association with porocarcinoma, including squamous cell carcinoma, basal cell carcinoma and tricholemmal carcinoma. Previous reports have indicated that the occurrence of malignant tumours in combination with porocarcinoma is extremely rare, in particular with regard to Bowen disease (BD). We report an uncommon case of porocarcinoma occurring synchronously in a single BD lesion in a 63‐year‐old woman with multiple BD lesions. The clinical and histological findings confirmed this diagnosis.  相似文献   
64.
Advancement in microelectromechanical system has facilitated the microfabrication of polymeric substrates and the development of the novel class of controlled drug delivery devices. These vehicles have specifically tailored three dimensional physical and chemical features which together, provide the capacity to target cell, stimulate unidirectional controlled release of therapeutics and augment permeation across the barriers. Apart from drug delivery devices microfabrication technology’s offer exciting prospects to generate biomimetic gastrointestinal tract models. BioMEMS are capable of analysing biochemical liquid sample like solution of metabolites, macromolecules, proteins, nucleic acid, cells and viruses. This review summarized multidisciplinary application of biomedical microelectromechanical systems in drug delivery and its potential in analytical procedures.  相似文献   
65.
Individuals with sudden unilateral deafness offer a unique opportunity to study plasticity of the binaural auditory system in adult humans. Stimulation of the intact ear results in increased activity in the auditory cortex. However, there are no reports of changes at sub-cortical levels in humans. Therefore, the aim of the present study was to investigate changes in sub-cortical activity immediately before and after the onset of surgically induced unilateral deafness in adult humans. Click-evoked auditory brainstem responses (ABRs) to stimulation of the healthy ear were recorded from ten adults during the course of translabyrinthine surgery for the removal of a unilateral acoustic neuroma. This surgical technique always results in abrupt deafferentation of the affected ear. The results revealed a rapid (within minutes) reduction in latency of wave V (mean pre = 6.55 ms; mean post = 6.15 ms; p < 0.001). A latency reduction was also observed for wave III (mean pre = 4.40 ms; mean post = 4.13 ms; p < 0.001). These reductions in response latency are consistent with functional changes including disinhibition or/and more rapid intra-cellular signalling affecting binaurally sensitive neurons in the central auditory system. The results are highly relevant for improved understanding of putative physiological mechanisms underlying perceptual disorders such as tinnitus and hyperacusis.  相似文献   
66.
67.
We present a patient with both dynamic left ventricular outflow tract obstruction and valvular aortic stenosis. The aortic valve was calcified, and velocities and gradients measured by continuous‐wave Doppler met standard criteria for severe aortic stenosis. The increased subvalvular velocities invalidated assumptions of the simplified Bernoulli equation; correction using the longer form of the Bernoulli equation suggested a lower but still significant gradient. The complex shape of the subvalvular spectral Doppler envelope indicated supranormal systolic function and dynamic left ventricular outflow obstruction. Left heart catheterization with an end‐hole catheter was required to determine the subvalvular and valvular components of the obstruction.  相似文献   
68.
69.
A 17‐year‐old boy presented with recurring severe dermatitis of the face of 5‐months duration that resembled impetigo. He had been treated with several courses of antibiotics without improvement. Biopsy showed changes consistent with allergic contact dermatitis and patch testing later revealed sensitization to benzoyl peroxide, which the patient had been using for the treatment of acne vulgaris.  相似文献   
70.
Guidelines and consensus on the management of patients with acne aim to give evidence-based, expert-group recommendations. This review compares current guidelines and consensus articles to provide a compilation of recommendations on the treatment of acne with oral isotretinoin. Ten common, relevant, clinical questions are addressed, based on published recommendations, including the indications of isotretinoin, the proposed daily dose, the cumulative isotretinoin dose and the laboratory monitoring needed. Recommendations on special considerations are also addressed, including the timing of procedures and the question of an association of depression or inflammatory bowel disease with isotretinoin. A major limitation is the use of different classification systems for acne across guidelines. The recommended daily dose ranges from 0.3 to 0.5 mg/kg in the European guidelines to up to 1 mg/kg in the US guidelines. A specific duration of treatment of at least 6 months is only recommended in the European guidelines. All guidelines report the need of strict pregnancy prevention measures. The European, French and US guidelines recommend to monitor for symptoms of depression. Important clinical questions that are inconsistently addressed in guidelines include the age indication, the recommendation for a cumulative dose, the timing of procedures, the association of isotretinoin with IBD, the recommendation for preventing acne flares and for appropriate laboratory monitoring. These topics should be clearly included in the recommendations of guidelines as they are often raised in everyday clinical practice.  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