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   2453318篇
  免费   188606篇
  国内免费   7970篇
耳鼻咽喉   33797篇
儿科学   80971篇
妇产科学   69049篇
基础医学   347834篇
口腔科学   68938篇
临床医学   215273篇
内科学   486686篇
皮肤病学   56397篇
神经病学   199444篇
特种医学   99927篇
外国民族医学   639篇
外科学   382698篇
综合类   53208篇
现状与发展   3篇
一般理论   712篇
预防医学   187975篇
眼科学   55375篇
药学   179406篇
  6篇
中国医学   4505篇
肿瘤学   127051篇
  2018年   24679篇
  2016年   22875篇
  2015年   25808篇
  2014年   35103篇
  2013年   52863篇
  2012年   68928篇
  2011年   73121篇
  2010年   44722篇
  2009年   42604篇
  2008年   69730篇
  2007年   75180篇
  2006年   76588篇
  2005年   75003篇
  2004年   71859篇
  2003年   70124篇
  2002年   67718篇
  2001年   111414篇
  2000年   114574篇
  1999年   96597篇
  1998年   28783篇
  1997年   25753篇
  1996年   26411篇
  1995年   25789篇
  1994年   24321篇
  1993年   22666篇
  1992年   78665篇
  1991年   77166篇
  1990年   75166篇
  1989年   72003篇
  1988年   67018篇
  1987年   65738篇
  1986年   62493篇
  1985年   60012篇
  1984年   45436篇
  1983年   38794篇
  1982年   23989篇
  1981年   21415篇
  1980年   20109篇
  1979年   42241篇
  1978年   30247篇
  1977年   25802篇
  1976年   23990篇
  1975年   25982篇
  1974年   30496篇
  1973年   29216篇
  1972年   27420篇
  1971年   25437篇
  1970年   23427篇
  1969年   22337篇
  1968年   21050篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
101.
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   
102.
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   
103.
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   
104.
105.
106.
107.
108.
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   
109.
110.
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   
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