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   7027篇
  免费   537篇
  国内免费   141篇
耳鼻咽喉   150篇
儿科学   118篇
妇产科学   130篇
基础医学   831篇
口腔科学   192篇
临床医学   729篇
内科学   1617篇
皮肤病学   82篇
神经病学   451篇
特种医学   158篇
外科学   1058篇
综合类   293篇
一般理论   7篇
预防医学   431篇
眼科学   116篇
药学   552篇
  1篇
中国医学   147篇
肿瘤学   642篇
  2023年   47篇
  2022年   100篇
  2021年   197篇
  2020年   117篇
  2019年   169篇
  2018年   191篇
  2017年   144篇
  2016年   185篇
  2015年   219篇
  2014年   280篇
  2013年   304篇
  2012年   457篇
  2011年   480篇
  2010年   309篇
  2009年   271篇
  2008年   397篇
  2007年   431篇
  2006年   354篇
  2005年   402篇
  2004年   356篇
  2003年   332篇
  2002年   282篇
  2001年   240篇
  2000年   196篇
  1999年   148篇
  1998年   55篇
  1997年   51篇
  1996年   42篇
  1995年   35篇
  1994年   36篇
  1993年   22篇
  1992年   82篇
  1991年   87篇
  1990年   75篇
  1989年   47篇
  1988年   37篇
  1987年   32篇
  1986年   42篇
  1985年   42篇
  1984年   30篇
  1983年   26篇
  1979年   34篇
  1978年   28篇
  1977年   18篇
  1976年   18篇
  1974年   26篇
  1973年   24篇
  1970年   25篇
  1969年   29篇
  1967年   26篇
排序方式: 共有7705条查询结果,搜索用时 15 毫秒
11.
Thymolipoma is a very rare mediastinal tumor. We reported a case of 52-year-old female with thymolipoma which was located in the cervicomediastinal area. The chest X-ray film revealed an abnormal shadow in the superior mediastinum. Computed Tomography (CT) clearly showed the existence of a large mass in the left side of the trachea. The angiogram showed that there was a stenosis on the left brachiocephalic vein. On June 13, 1988, median sternotomy was performed. A large tumor, about 5.5 x 13 x 5.5 cm, was found arising from the left cervical area. This tumor was excised completely and thymolipoma was diagnosed histopathologically. The post-operative course was very satisfactory.  相似文献   
12.
L M Chuang  H P Wu  T S Jou  T Y Tai  B J Lin 《Pancreas》1992,7(4):472-476
Islet amyloid polypeptide (IAPP) has been recently identified as the principal constituent of amyloid deposits in pancreatic islets of patients with type 2 (non-insulin-dependent) diabetes mellitus and causes insulin resistance in some target cells. In addition, glucose-induced insulin secretion is inhibited by IAPP. We studied the effect of IAPP on proinsulin biosynthesis in rat insulinoma (RINr) cells. Glucose at concentrations of 0, 15, 30, 60, 100, and 300 mg/dl stimulated proinsulin biosynthesis in a dose-responsive and and actino-mycin D-inhibitable manner after 6 h of incubation. At a glucose concentration of 300 mg/dl, IAPP decreased the mean responses of proinsulin biosynthesis to 61.2 and 29% at concentrations of 0.1 and 1 microM, respectively, compared with the IAPP-free control. In conclusion, IAPP inhibits glucose-induced proinsulin biosynthesis in RINr cells. IAPP might play an important role in the pathogenesis of type 2 diabetes mellitus.  相似文献   
13.
Paroxysmal nocturnal hemoglobinuria (PNH) is an acquired chronic hemolytic anemia associated with an unusual susceptibility to hemolytic crisis, infection, and venous thrombosis which would be aggravated by a number of factors including surgery. We report a case of PNH undergoing percutaneous transluminal coronary angioplasty and discuss the corresponding perioperative management.  相似文献   
14.
An acceleration transducer elicits an output voltage proportional to the deformation of the piezo crystal, in accordance with the twitch responses of the applied fingers. The reliability of such a transducer was evaluated by comparing induced twitch responses with those from a force transducer applied on the contralateral arm of an individual during neuromuscular block with vecuronium. The results obtained from twitch responses with the acceleration transducer during neuromuscular block were almost identical to those obtained with the force transducer. Also, the twitch heights due to acceleration of the examined thumb correlated extremely well with the twitch height due to twitch tension with the force transducer. It is concluded that the acceleration transducer may be a useful and reliable device for monitoring neuromuscular block, although responses during tetanic stimulation such as tetanic fade cannot be determined by the transducer.  相似文献   
15.
目的:总结重度烧伤传统疗法无效改为再生医学(MEBT/MEB0)技术治疗变化规律和临床验.方法:将我科l995年5月至2002年5月收治的院外采用传统疗法无效改用MEBT/MEBO技术治疗的38例重度烧伤病人临床资料进行回顾性总结,病人一旦入院创面均改用MEBT/MEBO治疗,初始予以彻底清创,规范用药、规范操作,规范认识;全身实行系统综合治疗措施.以临床观察和病人感觉评价治疗效果。结果:本组38例全部治愈,末植皮自行愈合者21例.占55.26%.深Ⅲ度创面自愿要求植皮者17例,占44.74%。经随访多数无增生性瘢痕,部分愈后有局限性瘢癌,质软无残废。结论:重度烧伤经传统疗法久治不愈或疗效欠佳病人.病情复杂,并发症较多治疗难度也较大,再生医学可有效改善以上缺陷和病症.是重度烧伤病人传统治疗无效时的理想疗法。  相似文献   
16.
BACKGROUND: This study investigated the utility of the alveolar - arterial oxygen pressure difference (AaDO (2)) in predicting the short-term prognosis of acute pulmonary embolism (PE). METHODS AND RESULTS: This study retrospectively enrolled 114 consecutive patients with acute PE, diagnosed by either spiral computed tomography or high probability ventilation - perfusion lung scans. During the first 24 h of admission, all patients had initial artery blood gas collected under room air. Patient exclusion criteria were chronic lung disease, septic emboli, and moderate and low probability lung scans. Patients were assigned to 2 groups based on either 30-day death or a 30-day composite event. Receiver operating characteristic analyses was used to determine the AaDO(2) cut-off value for predicting primary and composite endpoints. Statistical analysis demonstrated significant differences in AaDO(2) between the 30-day composite endpoint group and the 30-day composite event-free survival group (p=0.012). The AaDO(2) had a strong trend between the 30-day death group and the survival group (p=0.062). The best cut-off value for AaDO(2) was 53 mmHg and using this, the positive predictive value for 30-day death was 25% and the negative predictive value was 92%. For the 30-day composite endpoint, the positive predictive value for AaDO(2) was 35%, and the negative predictive value was 84%. In this study, thrombocytopenia was also an indicator of poor prognosis for patients with acute PE. CONCLUSION: The AaDO(2) measurement is a highly useful and simple measurement for predicting short-term prognosis in patients with acute PE. It has high negative predictive value and moderate positive predictive value for 30-day death and 30-day composite event. Aggressive thrombolytic treatment strategies should be considered for patients with an initial poor prognostic parameter (ie, AaDO(2) >or=53 mmHg).  相似文献   
17.
Hypertrophic scars (HS) are a consequence of abnormal wound healing. We examined fatty acids that are contained within, and participate in, every reaction through the membrane; then, we analyzed the percentage composition of the fatty acids in deepithelialized normal dermis (ND) and HS. In vivo HS samples were obtained from six patients undergoing surgical excision, and ND samples from five patients undergoing skin grafting surgery for excess. In vitro, cultured fibroblasts from HS and ND were also analyzed. The percentage composition of fatty acids extracted from all the samples was analyzed. In vivo, arachidonic acid (20:4) was significantly more abundant in HS than in ND, in the phospholipids from both whole tissue and cell membranes. In vitro, there were no significant differences among ND, HS, and 10% fetal calf serum. The results suggest that HS formation does not necessarily involve simple excess of 20:4; however, there are considerable differences in the percentage composition of 20:4 between ND and HS. Arachidonic acid probably participates in the formation and maintenance of HS, whereas in vitro cultured fibroblasts are affected largely by fetal calf serum.  相似文献   
18.
19.
BACKGROUND AND PURPOSE: Nosocomial methicillin-resistant Staphylococcus aureus (MRSA) infection is difficult to control. Due to a dramatic increase in the nosocomial MRSA infection rate at our hospital from 2000 to 2001, this study was conducted to identify the source of these infections and the effectiveness of control measures. METHODS: 179 healthcare workers (HCWs) were screened for carriage of MRSA. Starting in April 2001, all patients with MRSA infection or colonization were put in strict contact and cohort isolation. The bacterial isolates of HCW carriers and patients with MRSA infection from April 2001 to September 2001 were subjected to antimicrobial susceptibility testing by disk-diffusion method and molecular typing by pulsed-field gel electrophoresis (PFGE). RESULTS: Fifteen HCWs were found to be carriers of MRSA. They were all given topical mupirocin treatment. After these interventions, the nosocomial MRSA infection rate decreased from 1.23 to 0.53 per 1000 patient-days. All 61 MRSA isolates available for antimicrobial susceptibility testing and molecular typing were multidrug resistant. PFGE study revealed 2 predominant types, type C and type Y, comprising 36 and 12 isolates, respectively. CONCLUSIONS: The current study demonstrates the importance of measures to control nosocomial MRSA infections in hospitals that already have a high incidence of endemic MRSA infection. Elimination of carriage by healthcare workers, and strict contact and cohort isolation are the main effective measures.  相似文献   
20.
The purpose of this work was to evaluate the efficacy of labeling human mesenchymal stem cells (hMSCs) by ionic superparamagnetic iron oxide (SPIO) without a transfection agent and verifying its capability to be detected with clinical 1.5 T magnetic resonance (MR) at the single-cell level. Human hMSCs were incubated for 24 h with an ionic SPIO, Ferucarbotran. The labeling efficiency of hMSCs was determined by iron content measurement spectrophotometrically, and the influence of labeling on cell behavior was ascertained by examination of cell viability using the trypan blue exclusion method, cell proliferation analysis using MTT (3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay, mitochondrial membrane potential (MMP) change, differentiation capacity, and reactive oxygen species (ROS) production measured by dichlorofluorescein diacetate (DCFDA) fluorescent probe. Labeled hMSCs were scanned under 1.5 T MRI with three-dimensional (3D) and two-dimensional (2D) T(2)-weighted gradient echo (GRE) pulse sequences. Human hMSC labeling without transfection agent was efficient. The iron content in hMSCs was 23.4 pg Fe/cell. No significant change was found in viability, proliferation, MMP change, ROS production, or differentiation capacity. About 45.2% of the hMSCs could be detected using 1.5 T MRI at the single cell level with 3D GRE and four repetitions.  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