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   4690篇
  免费   315篇
  国内免费   67篇
耳鼻咽喉   71篇
儿科学   105篇
妇产科学   99篇
基础医学   355篇
口腔科学   317篇
临床医学   973篇
内科学   289篇
皮肤病学   22篇
神经病学   210篇
特种医学   184篇
外科学   806篇
综合类   630篇
预防医学   362篇
眼科学   140篇
药学   246篇
  9篇
中国医学   121篇
肿瘤学   133篇
  2024年   10篇
  2023年   79篇
  2022年   151篇
  2021年   244篇
  2020年   236篇
  2019年   146篇
  2018年   159篇
  2017年   188篇
  2016年   196篇
  2015年   209篇
  2014年   347篇
  2013年   308篇
  2012年   334篇
  2011年   290篇
  2010年   255篇
  2009年   221篇
  2008年   218篇
  2007年   223篇
  2006年   196篇
  2005年   131篇
  2004年   115篇
  2003年   107篇
  2002年   85篇
  2001年   70篇
  2000年   64篇
  1999年   50篇
  1998年   56篇
  1997年   38篇
  1996年   61篇
  1995年   19篇
  1994年   33篇
  1993年   26篇
  1992年   19篇
  1991年   23篇
  1990年   18篇
  1989年   19篇
  1988年   13篇
  1987年   16篇
  1986年   17篇
  1985年   18篇
  1984年   4篇
  1983年   7篇
  1982年   13篇
  1981年   9篇
  1980年   14篇
  1979年   3篇
  1977年   7篇
  1976年   1篇
  1974年   3篇
  1973年   2篇
排序方式: 共有5072条查询结果,搜索用时 234 毫秒
11.
Supine loss of consciousness is a relatively rare occurrence prompting investigations for underlying causes as diverse as cardiac arrhythmia, hypoglycaemia and nocturnal epilepsy. Neurally mediated syncope is rarely implicated as the cause of symptoms in supine loss of consciousness because of the absence of orthostatic stress and gravitational relative preservation of cerebral perfusion, but we report here on a case of recurrent, atypical and troublesome vasovagal syncope occurring at night while supine. Diagnosis aided by head-up tilt table testing and conservative management brought about complete resolution of symptoms.  相似文献   
12.
OBJECTIVE: To estimate the association of passenger seating position with the risk of death for passengers in traffic crashes. Design, setting, PARTICIPANTS: Matched cohort analysis of data from the National Highway Traffic Safety Administration Fatality Analysis Reporting System regarding 56 644 passengers in 23 308 passenger cars, light trucks, vans, and sport utility vehicles that crashed during 1990-2001. MAIN OUTCOME MEASURE: The adjusted risk ratio (aRR) for death of a rear seat passenger compared with a front seat passenger within 30 days of a crash. RESULTS: The aRR for all passengers in the rear seat in a crash was 0.79 (95% CI 0.77 to 0.82). This estimate varied by age, restraint use, and the presence of a front passenger airbag (p<0.001). For restrained passengers in cars with a front passenger airbag, the aRR was 0.62 (95% CI 0.48 to 0.81) for children 0-12 years, 0.96 (95% CI 0.88 to 1.06) for passengers 13-29 years, 1.03 (95% CI 0.93 to 1.15) for passengers 30-59 years, and 1.06 (95% CI 0.90 to 1.26) for passengers 60 years or older. The rear seat was associated with more protection in cars without front airbags and more protection for unrestrained passengers compared with restrained passengers. CONCLUSIONS: Previous studies have reported that the rear seat was safer for persons of all ages; thus seating a young child in the rear has often meant that older children and adults had to assume an increased risk of death by sitting in the front. These results suggest that when front passenger airbags are present and passengers are restrained, putting adults in front and children in back enhances child safety without sacrificing adult safety.  相似文献   
13.
目的 观察中药高臀位灌肠治疗慢性肾功能衰竭(chronic renal failure,CRF)的临床疗效.方法 将100例CRF患者随机分为两组,治疗组70例采用中药高臀化灌肠治疗,对照组30例口服活性炭治疗.结果 治疗组总有效率为88.6%,对照组总有效率为50.0%.结论 中药高臀位灌肠治疗CRF有效.  相似文献   
14.
根管治疗术远期疗效的影响因素   总被引:6,自引:1,他引:5  
根管治疗术(root canal therapy,RCT)是治疗牙髓病、根尖周病的主要方法.影响根管治疗术远期疗效的因素较多,而RCT前根尖周状态和根充位置是两大主要因素.  相似文献   
15.
Abstract Maxillary and mandibular anterior permanent teeth in 38 children aged 7–12 years were examined 2 × with an interval of 2 years to determine whether spontaneous facial/lingual tooth position changes were related to alterations of the widths of keratinized and attached gingiva and the clinical crown height. Measurements included dental plaque, gingival inflammation, probing depth, and width of keratinized and attached gingiva. In addition, study casts from the baseline and 2-year examinations were used to measure clinical crown height and tooth position. The results showed that significant alterations in the widths of the keratinized and attached gingiva took place when the teeth changed positions in facial or lingual directions. The changes in gingival widths could to some extent be coupled to changes in clinical crown height. In teeth moving lingually, the gingival widths increased and the clinical crown height decreased. In teeth moving facially, the gingival widths decreased, and the facial gingiva sometimes receded. These gingival alterations call for examination of the facial gingiva as part of the monitoring of the development of the permanent dentition.  相似文献   
16.
目的:研究开He患者的舌位置有无特征性变异。方法:利用舌背碘油造影方法,增加头颅侧位定位X线片上舌背的显影效果,在头颅侧位定位X线片上以舌体在固有口腔内的相对位置确定舌体的位置,通过开He与正常He者知位置的团体t检验比较,找出开He患者的舌位置变异特性。结果:开He患者与正常He者比较,舌根部与悬雍垂之间的间隙增大,舌背部与腭表面之间的间隙减小,舌尖部更靠近牙齿,结论:开He个体相对于正常He个体舌位置有向前,向上的变化特点,这可能是开He的病因之一。  相似文献   
17.
We studied how posture influences the effects of transdermal scopolamine on autonomic cardiovascular regulation in a randomized, double-blind, placebo-controlled crossover study of 10 healthy young volunteers. We recorded the electrocardiogram and auscultatory sphygmomanometric and continuous non-invasive finger arterial pressure (Finapres device) to obtain signals for the beat-by-beat R–R interval and systolic, mean and diastolic pressures. R–R interval and arterial pressure variabilities were characterized by power spectral analysis. Scopolamine increased the mean R–R intervals and reduced arterial pressure in both the supine and the standing positions, but did not affect blood pressure variability. Scopolamine increased the total variability of R–R interval and its mid- (0·07–0·15 Hz) and high- (0·15–0·40 Hz) frequency band power in the standing position during controlled breathing at 0·25 Hz. In the supine position, scopolamine did not affect R–R interval variability. In the deep breathing test, scopolamine increased the maximal expiratory–inspiratory R–R interval ratio. This study showed that low-dose scopolamine increases vagal cardiac inhibition in both supine and standing positions in healthy volunteers. However, scopolamine increases heart rate variability only in the standing position during partial vagal withdrawal. The study also demonstrates that transdermal scopolamine decreases blood pressure in healthy young subjects.  相似文献   
18.
本文采用俯卧拍背法缓解胆绞痛41例,其中23例经此法治疗后疼痛立即消失(56.1%);15例明显缓解(36.6%);3例缓解不明显(7.3%)。具有操作简便、安全,易被患者接受,值得推广。  相似文献   
19.
目的探讨原位低温阻断肾血管肾实质切开取石术治疗复杂性肾结石的效果。方法2000年3月~2005年1月采用原位低温阻断肾血管肾实质切开取石术治疗肾内型肾盂复杂性肾结石患者22例,术中快速静脉滴注肌苷2.0g,静滴20%甘露醇250ml。根据术前影像检查结果及术中所见选择肾切口径路:13例充填于各盏的鹿角状结石,行肾背侧Brodt线肾实质肾盏切开取石;5例肾下盏肾盂鹿角状结石,行肾盂肾实质联合切开取石;4例结石过多者,于肾皮质最薄处另作放射状切口取石。结果肾血管阻断时间平均45(30~60)min;手术时间平均110(90~180)min;平均失血量150(80~400)ml。结石一次取净21例,1例残余结石,术后2个月带双J管行ESWL碎石排出。术后1~2月复查肾功能,术前有肾功能损害的8例,血清Cr平均110.2μmol/L,血清BUN平均8.0mmol/L,均明显改善,其余患者肾功能无损害,无严重术后并发症。18例随访6个月~3年无一例复发。结论原位低温阻断肾血管肾实质切开取石术治疗复杂性肾结石安全有效、出血少、结石残留率低。  相似文献   
20.
Lymphoblastic lymphoma, an aggressive mediastinal mass, is recognized as serious threat to the patient in developing cardiac tamponade or airway obstruction. Surgical procedure is often required to relieve clinical emergency and to establish prompt pathological diagnosis. However, in such a patient, acute respiratory occlusion in the spine position can be a life-threatening complication during general anesthesia. We describe a 17-year-old man whose cardiac tamponade was treated by pericardial-pleural window through a left anterior thoracotomy in the lateral position. The patient recovered from hemodynamic compromise without showing respiratory occlusion during general anesthesia and remained in the lateral position until extubation. Pathological diagnosis was precursor T-lymphoblastic lymphoma. There were no complications attributable to the operative procedure. Further chemotherapy reduced the mediastinal mass in size after two weeks when the patient developed sepsis and died. Lateral position prevents respiratory occlusion during surgical procedure under general anesthesia in the patient of huge anterior mediastinal tumor with airway obstruction.  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