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   8931篇
  免费   336篇
  国内免费   52篇
耳鼻咽喉   340篇
儿科学   355篇
妇产科学   445篇
基础医学   575篇
口腔科学   370篇
临床医学   740篇
内科学   2176篇
皮肤病学   130篇
神经病学   451篇
特种医学   343篇
外科学   2175篇
综合类   133篇
预防医学   186篇
眼科学   313篇
药学   313篇
中国医学   23篇
肿瘤学   251篇
  2024年   3篇
  2023年   82篇
  2022年   123篇
  2021年   260篇
  2020年   141篇
  2019年   180篇
  2018年   217篇
  2017年   191篇
  2016年   289篇
  2015年   343篇
  2014年   476篇
  2013年   546篇
  2012年   690篇
  2011年   640篇
  2010年   421篇
  2009年   426篇
  2008年   654篇
  2007年   712篇
  2006年   636篇
  2005年   632篇
  2004年   547篇
  2003年   449篇
  2002年   368篇
  2001年   48篇
  2000年   25篇
  1999年   24篇
  1998年   41篇
  1997年   29篇
  1996年   33篇
  1995年   22篇
  1994年   13篇
  1993年   9篇
  1992年   14篇
  1991年   7篇
  1990年   5篇
  1989年   3篇
  1988年   2篇
  1987年   2篇
  1986年   2篇
  1985年   4篇
  1984年   2篇
  1983年   1篇
  1982年   2篇
  1980年   2篇
  1974年   1篇
  1970年   1篇
  1966年   1篇
排序方式: 共有9319条查询结果,搜索用时 15 毫秒
71.
Objectives:It is suggested that excessive calcium entry into neurons is the main triggering event in the initiation of epileptic discharges. We aimed to investigate the role of T and N type calcium channels in absence epilepsy experimental model.Results:Beta and delta recording ratios in 1 μM/5 μl mibefradil group was significantly different from basal and other dose-injected groups. Beta, alpha, and theta recordings in 0.2 μM/5 μl w-Conotoxin MVIIA group was significantly different from basal and other dose-injected groups. In w-Conotoxin MVIIA after mibefradil group, beta, alpha, and theta recording ratios were significantly different from basal and mibefradil group. Mibefradil and w-Conotoxin MVIIA significantly decreased the frequency and duration of SWDs. The decrease of frequency and duration of SWDs in mibefradil group was significantly different from w-Conotoxin MVIIA group. The frequency and duration of SWDs significantly decreased in w-Conotoxin MVIIA after mibefradil group compared with basal, mibefradil, and w-Conotoxin MVIIA groups.Conclusions:We concluded that both T and L type calcium channels play activator roles in SWDs and have positive effects on frequency and duration of these discharges. These results are related with their central effects more than peripheral effects.KEY WORDS: Epilepsy, mibefradil, T and N type calcium channels, Wistar Albino Glaxo/Rij rats, w-Conotoxin MVIIA  相似文献   
72.
Pituitary - Our aim was to investigate the changes in the composition of oral and gut microbiota in patients with newly diagnosed acromegaly and their relationship with IGF-1 levels. Oral and fecal...  相似文献   
73.
Ergin  Nesrin  Kılıç  Bilge Betül  Ergin  Ahmet  Varlı  Sema 《Sleep & breathing》2022,26(3):1299-1307
Sleep and Breathing - The aim was to determine sleep quality and related factors including restless leg syndrome in the 6th year medical students and medical residents in Pamukkale University,...  相似文献   
74.
75.
There is increased risk of systemic embolism during cardiopulmonary bypass in patients with a severely atherosclerotic ascending aorta. We report a coronary-coronary bypass in a 74-year-old man with a porcelain aorta. He underwent a proximal right coronary-distal right coronary artery bypass with a saphenous vein graft, combined with a pedicled arterial graft (left internal mammary artery) to the left anterior descending artery, in the presence of a beating heart without cardiopulmonary bypass. The patient survived without evidence of perioperative myocardial infarction or cerebrovascular accident. One year later, follow-up angiography showed graft patency with good distal run-off. Coronary-coronary bypass on a beating heart without cardiopulmonary bypass can be performed safely in a patient with porcelain aorta.  相似文献   
76.
Carbohydrate antigen 19-9 (CA19-9) has been used as a tumor marker in the diagnosis and differentiation of pancreatic cancers. However, significantly high levels of CA 19-9 in the absence of pancreatic malignancy have also been reported. We present a 50-year-old woman with a common bile duct stone and cholangitis, whose CA 19-9 level of 1.500 U/ml returned to normal after definitive treatment of choledocholithiasis.  相似文献   
77.
Behçets disease is a systemic vasculitis of unknown aetiology. Endothelial cell injury plays an important role in the pathogenesis and immunopathology of Behçets disease. E-selectin is expressed by activated endothelial cells. Because the selectin adhesion molecules are shed from activated cells, soluble forms of these proteins can be used as activation markers of endothelium (E-selectin). The pathogenesis of Behçets disease (BD) is closely related to endothelial cells, leucocyte functions and immunity. The aim of this study was to investigate circulating E-selectin adhesion molecules, which are known to play a significant part in the immune response especially by regulating interaction of the leucocytes with endothelium in BD. Plasma E-selectin concentrations were evaluated in 23 patients with BD and 20 healthy control subjects. The disease activity was evaluated by clinical manifestations (oral aphthous ulcer, genital ulceration, positive pathergy test, skin lesions, eye involvement, thrombophlebitis and arthritis) and by laboratory investigations [erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP)]. The patients were newly or previously diagnosed cases not taking any drug for BD. Levels of E-selectin were measured with commercially available sandwich enzyme-linked immunosorbent assay (ELISA) kits using human sE-selectin (cat. no: BMS 205). Plasma E-selectin concentrations of patients and controls were compared with the Mann-Whitney U test. Statistical significance was assigned to p values lower than 0.05. Serum levels (mean±SD) of soluble E-selectin (sE-selectin) were significantly higher in 23 patients with BD than in 20 healthy controls (53.2±18.2 ng/ml vs 33.8±7.5 ng/ml, p<0.0001). A statistically significant positive correlation was observed between sE-selectin levels and CRP and ESR in patients with BD (r=0.78, p<0.001 and r=0.56, p<0.01, respectively). Increases in the E-selectin in BD may be a direct consequence of the leucocyte and endothelium activations observed during the disease process. The noninvasive investigations can be used as biochemical markers for inflammation. This may provide additional information regarding disease activity along with the traditional indices such as ESR and CRP.  相似文献   
78.
Hepatic rupture with resulting hemoperitoneum due to metastatic cancer is uncommon. Reports in the literature have described a wide variety of neoplasms causing this usually fatal phenomenon. We describe a rare case of spontaneous rupture of hepatic metastases from gastric leiomyosarcoma. A 72-year-old male patient with sudden onset severe epigastric pain was rushed into emergency service. After examination, the patient underwent urgent operation withe possible diagnosis of perforated gastric or duodenal ulcer. During exploration, we determined bleeding mass on the diaphragmatic side of the left lobe of the liver and a mass on the posterior wall of the stomach. Hemostasis was provided.  相似文献   
79.
OBJECTIVE: Insulin like growth factor 1 (IGF-1) is recognized as a potent mitogen for many cancer cell lines and there is good evidence that lung cancer cells produce both IGF-1 and insulin like growth factor binding protein 3 (IGFBP-3). The aim of this study was to investigate the clinical significance of IGF-1 and IGFBP-3 levels in serum and in bronchoalveolar lavage (BAL) fluid by comparing lung cancer patients with healthy controls. METHODS: BAL fluid and serum samples were obtained from 24 lung cancer patients and 12 healthy controls, and were analyzed for IGF-1 and IGFBP-3 levels by a two site immunoradiometric assay. The recovered BAL fluid was standardized by albumin to remove the variable of dilution and the data was expressed in epithelial lining fluid (ELF). RESULTS: Serum IGF-1 and IGFBP-3 levels were lower in lung cancer patients, but the difference between the groups did not reach a statistical significance. IGF-1/IGFBP-3 ratio in ELF was significantly lower in lung cancer patients (P=0.035). Mean IGF-1 level in ELF was determined to be significantly lower in patients with distant metastasis (P=0.04). Serum IGF-1/IGFBP-3 ratio was found to be significantly lower in patients with distant (P=0.04) and nodal metastasis (P=0.03). Tumor stage was negatively correlated with IGF-1 level in ELF (P=0.05, r=-0.4) and serum IGF-1/IGFBP-3 ratio (P=0.04, r=-0.4). CONCLUSION: IGF-1 and IGFBP-3 levels both in serum and ELF might serve a clinical significance in patients with lung cancer. However, further studies comprising more cases are needed to investigate the clinical significance of IGF-1 and IGFBP-3 in lung cancer.  相似文献   
80.
OBJECTIVE: The purpose of this trial was to determine the spectrum of diseases with fever of unknown origin (FUO) in Turkey. METHODS: A prospective multicenter study of 154 patients with FUO in twelve Turkish tertiary-care hospitals was conducted. RESULTS: The mean age of the patients was 42+/-17 years (range 17-75). Fifty-three (34.4%) had infectious diseases (ID), 47 (30.5%) had non-infectious inflammatory diseases (NIID), 22 (14.3%) had malignant diseases (MD), and eight (5.2%) had miscellaneous diseases (Mi). In 24 (15.6%) of the cases, the reason for high fever could not be determined despite intensive efforts. The most common ID etiologies were tuberculosis (13.6%) and cytomegalovirus (CMV) infection (3.2%). Adult Still's disease was the most common NIID (13.6%) and hematological malignancy was the most common MD (7.8%). In patients with NIID, the mean duration of reaching a definite diagnosis (37+/-23 days) was significantly longer compared to the patients with ID (25+/-12 days) (p=0.007). In patients with MD, the mean duration of fever (51+/-35 days) was longer compared to patients with ID (37+/-38 days) (p=0.052). CONCLUSIONS: Although infection remains the most common cause of FUO, with the highest percentage for tuberculosis, non-infectious etiologies seem to have increased when compared with previous studies.  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