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   777188篇
  免费   60561篇
  国内免费   28975篇
耳鼻咽喉   8371篇
儿科学   13457篇
妇产科学   14834篇
基础医学   97539篇
口腔科学   18402篇
临床医学   84899篇
内科学   133973篇
皮肤病学   12947篇
神经病学   47457篇
特种医学   28468篇
外国民族医学   312篇
外科学   97215篇
综合类   80759篇
现状与发展   88篇
一般理论   100篇
预防医学   46461篇
眼科学   20747篇
药学   73658篇
  437篇
中国医学   26824篇
肿瘤学   59776篇
  2023年   6147篇
  2022年   15628篇
  2021年   21120篇
  2020年   16131篇
  2019年   14627篇
  2018年   16902篇
  2017年   15281篇
  2016年   14434篇
  2015年   20962篇
  2014年   26906篇
  2013年   26962篇
  2012年   39070篇
  2011年   42794篇
  2010年   28107篇
  2009年   23827篇
  2008年   31531篇
  2007年   32112篇
  2006年   31085篇
  2005年   29183篇
  2004年   22178篇
  2003年   21487篇
  2002年   18954篇
  2001年   38887篇
  2000年   39158篇
  1999年   33893篇
  1998年   10976篇
  1997年   9804篇
  1996年   8188篇
  1995年   7509篇
  1994年   6522篇
  1993年   5134篇
  1992年   19575篇
  1991年   17846篇
  1990年   16797篇
  1989年   16238篇
  1988年   14502篇
  1987年   13735篇
  1986年   12498篇
  1985年   11436篇
  1984年   7605篇
  1983年   6114篇
  1982年   2989篇
  1979年   5808篇
  1978年   3479篇
  1977年   3077篇
  1975年   2729篇
  1974年   3174篇
  1973年   2992篇
  1972年   2928篇
  1971年   2855篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
101.
102.
103.
李艳蓉 《河南中医》2007,27(1):18-18
笔者毕业后十余年中,临床上遇到心脑血管病人大部分正在应用西药治疗,中医讲究辨证论治,西药是否影响中医的辨证,临床上脉象是否随着西药运用而改变呢?中医脉象学是中医诊病、治病重要手段,望闻问切中“切诊”是主要组成部分。脉象变化是辨证论治重要依据,求证离不开脉象,组成脉象的主要因素及原因有:①脉位:脉动显现部位的浅深,脉位表浅为浮脉,深沉为沉弦;②至数:脉搏的频率,以一个呼吸周期为单位,一息脉来四~五至为平脉,一息六至为数脉,一息三至为迟脉;③脉长:脉动应指的轴向范围长短,越超三部脉象称为长脉,应指不及三部,但见关部或寸部者…  相似文献   
104.
105.
BACKGROUND: Stress can aggravate the allergic inflammation, but determinants of disturbed immune regulation are largely unknown. OBJECTIVE: To determine systemic immunological, local inflammatory and functional airway responses to stress in healthy and atopic individuals. METHODS: Forty-one undergraduate students, 22 with allergy of whom 16 had asthma, and 19 healthy controls, were studied in a low-stress period and in association with a large exam. Subjects completed questionnaires on stress and health behaviours, underwent lung function tests, bronchial methacholine challenge, measurements of exhaled nitric oxide and urine cortisol. Blood cells were phenotyped, and cytokines from mononuclear blood cells were analysed. RESULTS: Perceived stress and anxiety increased in both groups during the exam period while cortisol increased only in the atopy group. Cytokine production decreased broadly in response to stress in both groups, which was paralleled by an increase in the proportion of regulatory T cells (CD4(+)CD45RO(+)CD25(bright)). Interestingly, atopic individuals, but not controls, reacted with a decreased T-helper type 1/T-helper type 2 (Th1/Th2) ratio and a decrease in natural killer (NK) cell numbers in response to stress. In control subjects only, exhaled nitric oxide decreased and forced expiratory volume in one second increased during stress. CONCLUSION: Atopic and non-atopic subjects shared some immune changes in response to stress, such as a dramatic decline in cytokines and an increase in the number of regulatory T cells in peripheral blood. However, other stress-induced immune changes were unique to atopic individuals, such as a skewed Th1/Th2 ratio and reduced NK cell numbers, indicating that some pathogenic mechanisms in atopics may be more strongly affected by stress than others.  相似文献   
106.
107.
Paradoxical embolism, describing the passage of venous or right-sided cardiac thrombus into the arterial or systemic circulation through patent foramen ovale, is an uncommon cause of acute arterial occlusion. Here, we report acute Leriche syndrome in a young woman attributable to paradoxical embolism. Ischaemia, patent foramen ovale, and venous thrombosis were the triad of evidence for paradoxical embolism.  相似文献   
108.
BACKGROUND: Although many histopathologic factors in squamous cell carcinoma of the tongue predict the prognosis, the major predictive factors have not been identified clearly. This study analyzed the prognostic value of the histologic grade at the deep invasive front of tongue squamous cell carcinoma. METHODS: The clinicopathologic features of 124 consecutive patients seen between January 1985 and December 1999 with previously untreated squamous cell carcinoma of the tongue were reviewed. Their mean age was 58.5 years (range: 23-90) and the male-female ratio was 1.8: 1 (79 men and 45 women). There were 41, 40, 30, and 13 cases at stage I to stage IV, respectively. The clinicopathologic factors, especially the histologic grade at the deep invasive front (invasive front grade, IFG), were analyzed to determine factors predicting prognosis. RESULTS: The 5-year disease-free survival rate of the patients treated with curative aim only was 66.7%. Clinicopathologic factors significantly associated with the prognosis were T classification, tumor size, stage classification, tumor depth, macroscopic appearance, cervical lymph node metastasis (nodal metastasis), microvascular invasion, and IFG. In a multivariate analysis, patients with tumor depth >/=4 mm, IFG >/=8 points, and nodal metastasis had a reduced disease-free survival and IFG >/=11 points had a predictive value for nodal metastasis (odds ratio: 7.34; P = 0.0019). CONCLUSION: This study found that a high IFG malignancy score had a high prognostic value for squamous cell carcinoma of the tongue.  相似文献   
109.
110.
Effects of human recombinant TNF on the tumor blood vessels and on the thrombus formation were investigated in relation to its mode of antitumor action against Meth-A sarcoma transplanted in BALB/c mice. The extent of the blood vessel lesion was evaluated by using transparent chamber placed in the mouse skin. Bleeding, hyperemia and congestion were observed at 1-2h, 4-6h and 24h after TNF (1 X 10(4)U/mouse) administration, respectively. In contrast, no histological changes in the normal blood vessels were observed microscopically following TNF injection. Thrombus formation was evoked in the tumor vessels 4h after TNF injection. However, when thrombus formation was prevented by heparin, no difference was observed among antitumor action of TNF against Meth-A fibrosarcoma necrotic response and the rate of complete cure. These results suggest that the direct effects of TNF causing lesions in the tumor blood vessels plays an important role in its antitumor action.  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