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   256442篇
  免费   10535篇
  国内免费   566篇
耳鼻咽喉   3655篇
儿科学   7805篇
妇产科学   5862篇
基础医学   35813篇
口腔科学   8868篇
临床医学   15728篇
内科学   57132篇
皮肤病学   6975篇
神经病学   21260篇
特种医学   6648篇
外国民族医学   3篇
外科学   31151篇
综合类   1204篇
一般理论   59篇
预防医学   28203篇
眼科学   6385篇
药学   19106篇
中国医学   1072篇
肿瘤学   10614篇
  2023年   1435篇
  2022年   1167篇
  2021年   4228篇
  2020年   2395篇
  2019年   4599篇
  2018年   8079篇
  2017年   5172篇
  2016年   5156篇
  2015年   5758篇
  2014年   6347篇
  2013年   9693篇
  2012年   16301篇
  2011年   17289篇
  2010年   8682篇
  2009年   6349篇
  2008年   13965篇
  2007年   15089篇
  2006年   14152篇
  2005年   13921篇
  2004年   12809篇
  2003年   12073篇
  2002年   11340篇
  2001年   7568篇
  2000年   8399篇
  1999年   6526篇
  1998年   1232篇
  1992年   3229篇
  1991年   2831篇
  1990年   2721篇
  1989年   2316篇
  1988年   2191篇
  1987年   2065篇
  1986年   2098篇
  1985年   1939篇
  1984年   1434篇
  1983年   1209篇
  1979年   1524篇
  1978年   1018篇
  1977年   979篇
  1976年   962篇
  1975年   1114篇
  1974年   1414篇
  1973年   1489篇
  1972年   1396篇
  1971年   1349篇
  1970年   1250篇
  1969年   1330篇
  1968年   1361篇
  1967年   1200篇
  1966年   1078篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
72.
73.
Hepatic encephalopathy is a reversible state of altered cognition that may occur in patients with acute or chronic liver disease or porto-systemic shunt, and in which known neurological or psychiatric signs may develop. Nitrogenated substances from intestinal digestion reach the brain without being cleared by their passage through the liver due to the presence of porto-systemic shunt. We report two cases of patients with porto-systemic shunt diagnosed with recurrent chronic hepatic encephalopathy refractory to conventional medical treatment. They were satisfactorily treated with shunt embolization using interventionist radiology techniques.  相似文献   
74.
Ligneous periodontitis (LP) is a rare periodontal disease in which plasminogen deficiency and fibrin deposition both play a part, resulting in characteristic gingival enlargement and periodontal breakdown. Recent data suggest that oxidant/antioxidant changes are significant in the pathology of oral diseases. This study examines the gingival histopathology in 2 cases with LP. To examine the antioxidant (AO) status, the activity of the major AOs glutathione (GSH), catalase (CAT), and glutathione S-transferase (GST) and the malondialdehyde (MDA) levels, a product of lipid peroxidation, were measured and compared with healthy control subjects. The histopathologic examination of the gingiva revealed subepithelial fibrin accumulation and irregular extensive downward proliferation of the epithelium. Biochemical analysis showed that the CAT, GST, and MDA levels were higher in LP patients than in the control subjects, and the GSH level was lower. Our preliminary findings show that in LP, the AO capacity of the gingiva changes or decreases and lipid peroxidation increases, which suggests that oxidative stress is involved in the pathology of the periodontal breakdown observed in this disease.  相似文献   
75.
Five patients with idiopathic transient osteoporosis were examined. Bone scanning and MRI was helpful in the diagnosis to differentiate of necrosis and all patients recovered completely with conservative and symptomatic treatment. There was no history of trauma in all patients. MRI was realized previously in all cases to confirm the diagnosis and after the resolution of symptomathology.  相似文献   
76.
Members of the R7 subfamily of regulators of G-protein signaling (RGS) proteins (RGS6, RGS7, RGS9-2, and RGS11) are found in the mouse CNS. The expression of these proteins was effectively reduced in different neural structures by blocking their mRNA with antisense oligodeoxynucleotides (ODNs). This was achieved without noticeable changes in the binding characteristics of labeled beta-endorphin to opioid receptors. Knockdown of R7 proteins enhanced the potency of antinociception promoted by morphine and [D-Ala(2), N-MePhe(4), Gly-ol(5)]-enkephalin (DAMGO)-both agonists at mu-opioid receptors. The duration of morphine analgesia was greatly increased in RGS9-2 and in RGS11 knockdown mice. The impairment of R7 proteins brought about different changes in the analgesic activity of selective delta agonists. Knockdown of RGS11 reduced [D-Ala(2)]deltorphin II analgesic effects. Those of RGS6 and RGS9-2 proteins caused [D-Ala(2)]deltorphin II to produce a smoothened time-course curve-the peak effect blunted and analgesia extended during the declining phase. RGS9-2 impairment also promoted a similar pattern of change for [D-Pen(2,5)]-enkephalin (DPDPE). RGS7-deficient mice showed an increased response to both [D-Ala(2)]deltorphin II and DPDPE analgesic effects. A single intracerebroventricular (i.c.v.) ED(80) analgesic dose of morphine gave rise to acute tolerance in control mice, but did not promote tolerance in RGS6, RGS7, RGS9-2, or RGS11 knockdown animals. Thus, R7 proteins play a critical role in agonist tachyphylaxis and acute tolerance at mu-opioid receptors, and show differences in their modulation of delta-opioid receptors.  相似文献   
77.
Abstract – Traumatic dental injuries often occur to the teeth and their supporting tissues and they are the main reasons for emergency visit to a dental clinic. Management of a fracture depends on its position and the extent of root involvement. Horizontal root fractures are not seen frequently and the treatment consists of reduction and long‐term rigid fixation of the coronal segment. The present case demonstrates the successful management of two horizontally fractured maxillary central incisors with a follow‐up period of 9 months.  相似文献   
78.
79.
80.
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