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   2131篇
  免费   126篇
  国内免费   75篇
耳鼻咽喉   1篇
儿科学   171篇
妇产科学   27篇
基础医学   238篇
口腔科学   58篇
临床医学   258篇
内科学   507篇
皮肤病学   73篇
神经病学   112篇
特种医学   393篇
外科学   95篇
综合类   51篇
预防医学   95篇
眼科学   32篇
药学   112篇
  2篇
肿瘤学   107篇
  2023年   4篇
  2022年   4篇
  2021年   11篇
  2020年   14篇
  2019年   15篇
  2018年   33篇
  2017年   22篇
  2016年   23篇
  2015年   40篇
  2014年   49篇
  2013年   64篇
  2012年   40篇
  2011年   44篇
  2010年   89篇
  2009年   91篇
  2008年   55篇
  2007年   97篇
  2006年   61篇
  2005年   61篇
  2004年   34篇
  2003年   22篇
  2002年   31篇
  2001年   41篇
  2000年   32篇
  1999年   34篇
  1998年   128篇
  1997年   156篇
  1996年   131篇
  1995年   108篇
  1994年   115篇
  1993年   98篇
  1992年   32篇
  1991年   38篇
  1990年   40篇
  1989年   56篇
  1988年   48篇
  1987年   47篇
  1986年   57篇
  1985年   48篇
  1984年   30篇
  1983年   18篇
  1982年   25篇
  1981年   34篇
  1980年   30篇
  1979年   8篇
  1978年   9篇
  1977年   18篇
  1976年   26篇
  1975年   14篇
  1970年   2篇
排序方式: 共有2332条查询结果,搜索用时 31 毫秒
111.
The aim of this study was to assess the clinical safety of performing microlaryngeal surgery (MLS) under general anaesthesia in selected patients in the ambulatory setting. Twenty-two adult patients were scheduled to have tissue specimens of the larynx taken by biopsy (54%), for vocal cord polypectomy (41%) or for vocal cord cyst excision (5%). Twenty-one ASA I and II patients (95%) were discharged home the same day of the procedure. Two of them presented with laryngospasm after extubation of the trachea. One ASA III patient (5%) had to be admitted overnight because of severe laryngospasm and bronchospasm, but was discharged the day after the operation. None of the patients had significant complications after leaving the recovery room (mean stay 85 min). There were no re-admissions to the hospital. Our data suggests that microlaryngeal surgery in selected patients can be safely performed on a day case basis.  相似文献   
112.
目的:目前有关骨髓间充质干细胞向内皮细胞诱导分化的研究较少。本实验分离和培养人骨髓间充质干细胞,用带有VEGF165的质粒转染人骨髓间充质干细胞,探讨血管内皮生长因子对其体外诱导分化的作用。 方法:实验于2005—04/2006—04在吉林大学人兽共患病教育部重点实验室完成。取成人的已排除血液系统肿瘤疾病的新鲜骨髓(自愿提供),采用Percoll梯度分离培养骨髓间充质干细胞,于倒置显微镜下观察细胞形态变化和生长情况。原代细胞培养至增殖接近融合状态时,单克隆培养法分离传代培养,扩增骨髓间充质干细胞。采用流式细胞术检测细胞免疫学表型。在原核细胞大肠杆菌DH5α中复制扩增和提取,纯化、克隆pcDNA3.0-VEGF165质粒。用脂质体转染法转染骨髓间充质干细胞:应用流式细胞术检测诱导后骨髓间充质干细胞免疫学表型变化j并采用免疫荧光染色鉴定转染情况,并设质粒空载和未转染的骨髓间充质干细胞为对照。 结果:人骨髓间充质干细胞原代培养1周后,造血细胞消失,贴壁细胞体积增大,呈现梭形外观,有粗大的细胞突起伸出。2周后细胞融合成单层,梭形突起变长,排列有明显的方向性,细胞排列成旋涡状、网状、辐射状。流式细胞术显示,人骨髓间充质干细胞免疫学表型CD44、CD29阳性,CD34、CD31、CD45阴性。VEGF165诱导骨髓间充质千细胞后CD44表达明显降低,CD31明显升高。免疫荧光染色显示,用FITC标记后的VEGF抗体使细胞显现绿色荧光,用cy3标记的CD31抗体使细胞显现了红色荧光。 结论:转染后的骨髓间充质干细胞细胞表型发生明显转变,CD31表达率明显增高,呈现典型的内皮细胞的表型特征,这说明骨髓间充质干细胞具有向内皮细胞分化的潜能。  相似文献   
113.
This community situational analysis determined factors impacting the utilization of maternal health services in South Africa. Quantitative and qualitative research methods were used, including semistructured household interviews, case studies of women with no antenatal care and/or home birth, and verbal/social autopsies of maternal and infant deaths, conducted in three diverse sites across the country. Data analysis used quantitative statistics for the semistructured interviews and a qualitative thematic content approach for the case studies and verbal/social autopsies. Each component was analyzed separately and then triangulated. The following themes emerged: 1) transport and distance to care were the biggest problems, particularly in rural areas; 2) providers' communication with families was very poor; 3) health-seeking behavior was better than anticipated; 4) treatment by health providers and quality of care showed mixed results; 5) HIV/AIDS is a major issue; however, basic maternity and neonatal service quality cannot be overlooked; and 6) families and communities are an untapped resource for improving maternal and neonatal health. Implications for maternal and infant health care in developing countries are discussed, with a particular focus on barriers to utilization and involvement of communities and families in maternity care.  相似文献   
114.
115.
The three D’s of Geriatric Psychiatry—delirium, dementia, and depression—represent some of the most common and challenging diagnoses for older adults. Delirium is often difficult to diagnose and treatment is sometimes controversial with the use of antipsychotic medications, but it is common in a variety of patient care settings and remains an independent risk factor for morbidity and mortality in older adults. Dementia may affect a significant number of older adults and is associated with delirium, depression, frailty, and failure to thrive. Treatment of dementia is challenging and while medication interventions are common, environmental and problem solving therapies may have some of the greatest benefits. Finally, depression increases with age and is more likely to present with somatic complaints or insomnia and is more likely to be reported to a primary care physician than any other healthcare provider by older adults. Depression carries an increased risk for suicide in older adults and proven therapies should be initiated immediately. These three syndromes have great overlap, can exist simultaneously in the same patient, and often confer increased risk for each other. The primary care provider will undoubtedly benefit from a solid foundation in the identification, classification, and treatment of these common problems of older adulthood.  相似文献   
116.
Ventilator-associated pneumonia (VAP) is a common cause of morbidity, antibiotic use, increased length of stay and, possibly, increased mortality in ICU patients. Colonization of the oropharyngeal cavity with potentially pathogenic micro-organisms is instrumental in the pathogenesis of VAP, and selective oropharyngeal decontamination (SOD) with antibiotics (AB-SOD) or antiseptics, such as chlorhexidine gluconate (CHX-SOD), has been associated with reduced incidences of VAP. In a recent issue of Critical Care Scannapieco and colleagues investigated differences in oropharyngeal colonization between mechanically ventilated patients receiving oropharyngeal decontamination with 0.12% CHX-SOD either once or twice daily compared to placebo. CHX-SOD was associated with a reduction in Staphylococcus aureus colonization, but the study was underpowered to demonstrate a reduction in VAP incidence. We urgently need well-designed and adequately powered studies to evaluate the potential benefits of CHX-SOD on patient outcome in ICUs.  相似文献   
117.
在当前医学教育持续变革的背景中,医学教师的专业发展成为广泛关注的焦点.为了解目前美国以提高教师的教学技能为目标的教师专业发展(faculty development,FD)活动的参与率、课程设计、教学方法和评估策略等情况,美国约翰·霍普金斯大学预防、流行病学和临床研究中心采取邮件调查的方式,对美国277家教学医院进行了调查.  相似文献   
118.
Background Bedbugs (Cimex lectularius) have been feeding on sleeping human beings since prehistory. In Europe, bed bugs were common and endemic until World War II when improved body and home hygiene, and widespread use of insecticides led to almost complete eradication. Current evidence indicates that bedbugs are making a comeback in Europe, USA, Canada and Australia. In our practice in Southern France, we observed several cases within a period of only 1 year. Objectives Based on this experience, we conducted an epidemiological study to evaluate the status of bedbugs in France. Methods During summer 2009, we mailed a short questionnaire to all hospital professors in the CEDEF (Collège des Enseignants de Dermatologie de France) asking four questions: number of suspected diagnosis of bedbugs in the year 2009, and number of certain positive diagnosis, difficulties in treatment, use of a pest control professional for treatment, and finally personal opinion on actual incidence of bedbugs, compared with past years. Results Of the 84 questionnaires sent, there were only 26 responses despite two reminders. The responses were predominantly southern France, probably as a result of intensive immigration and increased travel and trade. Difficulties encountered during diagnosis and treatment are also mentioned. Utilizing the services of entomological experts and pest control professionals is essential. Conclusions France has the same experience regarding the resurgence of bedbugs as several European countries, USA, Canada and Australia, especially the southern regions. This emerging health problem has to be known by dermatologists. A national programme has been launched in France to assess actual incidence and study C. lectularius‐ related diseases.  相似文献   
119.
Background Skin cancer surgery is usually performed on the face, and more specifically on and around the midfacial apertures. Each defect generated by the exeresis of a face tumor can be repaired by various advancement, rotation or transposition flaps techniques. Therefore the choice of the closure axis of a defect and its cicatricial and orificial consequences is decisive. Results The closure of a defect is usually made by symmetrically suturing its edges, across the incision axis according to the rule of halves. However, the closure axis of a defect is intentional and characterized by the subcutaneous suture axis which determines the induced tension orientation, and thus the possible displacement of the aperture free margins. The horizontal stretching principle guarantees the lack of impact on the 3 major apertures of the midfacial frame: eye, nostril and mouth. Conclusions This biomechanical concept is decisive to repair midfacial defect with functional and aesthetic results. It also provides objective arguments for the reparative techniques prioritization and the ability to codify those to be recommended as first‐line treatment in the surgical management of the face cutaneous tumours.  相似文献   
120.
Amyloid involvement of the breast is infrequently reported and may have clinical and radiological features suspicious for a primary breast malignancy. We describe a case of amyloid of the breast in which asymptomatic mammographic findings were suspicious for locally recurrent disease in a patient with previously treated breast cancer.  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