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   550篇
  免费   21篇
  国内免费   1篇
儿科学   17篇
妇产科学   26篇
基础医学   48篇
口腔科学   7篇
临床医学   69篇
内科学   107篇
皮肤病学   4篇
神经病学   52篇
特种医学   7篇
外科学   86篇
综合类   5篇
预防医学   61篇
眼科学   3篇
药学   49篇
中国医学   2篇
肿瘤学   29篇
  2024年   4篇
  2023年   2篇
  2022年   2篇
  2021年   8篇
  2020年   9篇
  2019年   12篇
  2018年   10篇
  2017年   5篇
  2016年   4篇
  2015年   14篇
  2014年   18篇
  2013年   24篇
  2012年   31篇
  2011年   36篇
  2010年   18篇
  2009年   10篇
  2008年   27篇
  2007年   39篇
  2006年   37篇
  2005年   32篇
  2004年   44篇
  2003年   25篇
  2002年   28篇
  2001年   8篇
  2000年   12篇
  1999年   8篇
  1998年   9篇
  1997年   4篇
  1996年   2篇
  1994年   2篇
  1993年   3篇
  1992年   4篇
  1991年   10篇
  1990年   7篇
  1989年   4篇
  1988年   2篇
  1987年   6篇
  1986年   4篇
  1985年   9篇
  1984年   5篇
  1983年   5篇
  1982年   2篇
  1981年   3篇
  1980年   2篇
  1979年   4篇
  1977年   2篇
  1976年   3篇
  1967年   5篇
  1965年   2篇
  1930年   1篇
排序方式: 共有572条查询结果,搜索用时 15 毫秒
561.
562.
563.
The purpose of this study was to evaluate the inertial properties and forces required to initiate movement on two different surfaces in a sample of three commonly prescribed gait trainers. Tests were conducted in a laboratory setting to compare the Prime Engineering KidWalk, Rifton Pacer, and Snug Seat Mustang with and without a weighted anthropometric test dummy configured to the weight and proportions of a 4-year-old child. The Pacer was the lightest and the KidWalk the heaviest while footprints of the three gait trainers were similar. Weight was borne fairly evenly on the four casters of the Pacer and Mustang while 85% of the weight was borne on the large wheels of the mid-wheel drive KidWalk. These differences in frame style, wheel, and caster style and overall mass impact inertial properties and forces required to initiate movement. Test results suggest that initiation forces on tile were equivalent for the Pacer and KidWalk while the Mustang had the highest initiation force. Initiation forces on carpet were lowest for the KidWalk and highest for the Mustang. This initial study of inertia and movement initiation forces may provide added information for clinicians to consider when selecting a gait trainer for their clients.  相似文献   
564.
OBJECTIVES: No reliable methods are available for determining application of percutaneous coronary intervention for treatment of equivocal tandem lesions. We investigated whether coronary pressure measurement is useful for determining the lesion that requires percutaneous coronary intervention in tandem lesions. METHODS: We measured coronary pressure in 72 consecutive patients with tandem lesions. Myocardial fractional flow reserve (FFRmyo) was obtained as the ratio of coronary pressure distal to the lesion/aortic pressure under maximal hyperemia. If the FFRmyo across the tandem lesions was >or=0.75, we deferred percutaneous coronary intervention for the lesion. When the tandem lesions showed FFRmyo<0.75, percutaneous coronary intervention was performed on the lesion that showed angiographically higher stenosis. When FFRmyo was <0.75 after one-lesion percutaneous coronary intervention, this intervention was carried out on the remaining lesion. RESULTS: We deferred percutaneous coronary intervention for 26 patients (36.1%), and performed percutaneous coronary intervention in 46 patients (63.8%). We performed percutaneous coronary intervention for one lesion in 19 patients (26.4%) and for both lesions in 27 patients (37.5%). Among patients in whom percutaneous coronary intervention was deferred, only two patients (7.7%) required target lesion revascularization during the follow-up period. This rate was not higher than that in the 46 patients who underwent percutaneous coronary intervention for one or two lesions (six patients, 13.0%). Similarly, the target lesion revascularization in lesions with initially deferred percutaneous coronary intervention (5.6%, 4/71 lesions) was not higher than that in lesions with percutaneous coronary intervention (15.1%, 11/73 lesions). Major cardiac events, cardiac death and acute myocardial infarction, did not occur in patients with deferred percutaneous coronary intervention and in those with percutaneous coronary intervention during the follow-up period. CONCLUSION: Our results clearly showed that coronary pressure measurement was clinically useful for identifying equivocal tandem lesions requiring percutaneous coronary intervention.  相似文献   
565.
BACKGROUND: Erythrocytapheresis (ECP), automated red blood cell exchange, is increasingly being used for chronic transfusion therapy in sickle cell disease (SCD) as it is an isovolumetric transfusion, is more effective in lowering hemoglobin (Hb)S, and can limit iron overload. Because ECP requires increased blood exposure compared to simple transfusions there is concern for increased transfusion complications, including alloimmunization. We compared alloimmunization rates between patients receiving simple or exchange chronic transfusions. STUDY DESIGN AND METHODS: Data were retrospectively collected for 45 SCD patients (n = 23 simple, n = 22 ECP) on a chronic transfusion program as of December 2010 to determine the rate of antibody formation (antibodies formed per 100 units transfused). RESULTS: The 45 patients received 10,949 units and formed six new alloantibodies during the study period (1994‐2010); therefore, the overall alloimmunization rate was 0.055 alloantibodies per 100 U. There were three antibodies formed in three patients on ECP, one allo (anti‐rhi) and two autoantibodies. There were six antibodies in four patients on a simple transfusion program, five allo (anti‐Lea, M, D, C, and Kpa) and one autoantibody. The ECP group received significantly more blood (338.5 units/patient vs. 152.2 units/patient, p = 0.001). The rate of antibody formation (auto plus allo) was 0.040 antibodies per 100 U in the ECP group and 0.171 antibodies per 100 U in the simple transfusion group (p = 0.04). The alloantibodies formed per 100 units was 0.013 in the ECP group and 0.143 in the simple transfusion group (p = 0.03). CONCLUSION: Chronic ECP should be considered in patients requiring optimal management of HbS levels and iron burden. Concerns about increased alloimmunization with ECP may be unjustified.  相似文献   
566.
The ethics of invasive mechanical ventilation for children with the neurodegenerative disease Spinal Muscular Atrophy Type I (SMA I) is highly debated, and wide variability in clinical outcomes exists internationally. We conducted this international survey to identify physician characteristics associated with recommendation for tracheostomy and ventilation for SMA I. A cross-sectional online survey was distributed to 1,772 pediatric pulmonologists and pediatric intensivists from online membership directories of American Thoracic Society, American College of Chest Physicians, and European Respiratory Society. Questions explored physician demographics, attitudes and experience with SMA and end-of-life care, knowledge of consensus guidelines, and recommendations for respiratory care of SMA I. A logistic regression model assessed the independent effects of physician variables on the recommendation for invasive ventilation for SMA I. A total of 367 (21%) physicians completed the survey; 82% were pediatric pulmonologists; and 16% pediatric intensivists. Seventy percent of respondents were from the U.S. Fifty percent of physicians were aware of SMA consensus guidelines. Physicians from Commonwealth countries (U.K., Canada, Australia, etc.) were less likely to recommend tracheostomy/ventilation than U.S. physicians (7% vs. 25%, P = 0.005). Logistic regression modeling identified years of experience, pediatric pulmonology specialty, agreement with a pro-life statement, and recommendation for non-invasive ventilation as predictive of recommendation for long-term invasive ventilation for SMA I. In the largest international survey on this topic, we identified regional differences in physician recommendation for invasive ventilation for children with SMA I. Our data demonstrate a need for increased awareness of consensus guidelines and further dialog about the physician role in variability of care for children with SMA I.  相似文献   
567.
Profound intraventricular hemorrhage (IVH) has devastating effects on neonates, leading to significant neurodevelopmental morbidity. We have developed a flexible fiberoptic ventriculoscope (Yamadori-type 8), which has a conspicuously high resolving power and is equipped with a bipolar coagulator and a working channel for irrigation. Four neonates with IVH were examined and treated for the first time using the flexible ventriculoscope. The patients had grade III or IV IVH on computed tomography scans and received endoscopic operations three to four weeks after birth. In patients with IVH, fragments of old hematomas were observed as brown masses because of the presence of hemosiderin, a characteristic endoscopic finding. We have found, for the first time, IVH due to rupture of the varices of septal veins, which could be cauterized endoscopically. Hydrocephalus was relieved by irrigation, third ventriculostomy, coagulation of the choroid plexus, and adequate placement of ventriculoperitoneal shunting was performed endoscopically. The flexible ventriculofiberscope could be a useful modality for early treatment of IVH in neonates because of the minimal invasiveness. The pathogenesis of IVH should be reviewed to include septal vein varices as a possible cause of IVH.  相似文献   
568.
569.
We report a case of a patient with primary cerebral neuroblastoma who has survived for 8 years. A 10-year-old boy was admitted to our hospital because of headache and nausea. CT scan on admission revealed a large cystic tumor on the right frontal lobe. Subtotal tumor resection was carried out. A second operation was performed for the residual tumors which were removed meticulously with confirmation of the absence of tumor cells on each frozen section. After tumor removal, YAG laser was applied at each local area. Histological diagnosis disclosed primary cerebral neuroblastoma. Because of postsurgical meningitis and parent's refusal, neither chemotherapy nor radiation therapy was performed. There have been no findings of the tumor recurrence during the last eight years, and now the patient is enjoying high school life to the full, without any neurological deficits. In reviewing the literature, outcomes of neuroblastoma cases are very poor. Our case seems to be one of the rare long-survival cases.  相似文献   
570.
    
Adverse childhood experiences are potentially traumatic events with long-lasting effects on the health and well-being of patients with autism spectrum disorder (ASD). It is important to clarify which types of long-lasting autism-related symptoms are influenced by childhood experiences to design future intervention studies. However, few studies have examined the association between childhood experiences and autistic symptoms in large samples of adults with ASD and individuals with typical development (TD). In this study, we evaluate the effects of adverse childhood experiences on multiple ASD phenotypes among both individuals with ASD and those with TD.  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