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   3041篇
  免费   192篇
  国内免费   14篇
耳鼻咽喉   29篇
儿科学   65篇
妇产科学   58篇
基础医学   302篇
口腔科学   123篇
临床医学   324篇
内科学   717篇
皮肤病学   88篇
神经病学   245篇
特种医学   110篇
外科学   330篇
综合类   14篇
一般理论   1篇
预防医学   243篇
眼科学   70篇
药学   179篇
中国医学   4篇
肿瘤学   345篇
  2024年   5篇
  2023年   30篇
  2022年   65篇
  2021年   144篇
  2020年   95篇
  2019年   110篇
  2018年   131篇
  2017年   84篇
  2016年   91篇
  2015年   110篇
  2014年   121篇
  2013年   167篇
  2012年   253篇
  2011年   279篇
  2010年   142篇
  2009年   121篇
  2008年   211篇
  2007年   218篇
  2006年   179篇
  2005年   169篇
  2004年   130篇
  2003年   135篇
  2002年   127篇
  2001年   20篇
  2000年   18篇
  1999年   16篇
  1998年   15篇
  1997年   12篇
  1996年   14篇
  1995年   7篇
  1994年   8篇
  1993年   3篇
  1992年   1篇
  1991年   2篇
  1990年   2篇
  1989年   1篇
  1988年   1篇
  1985年   1篇
  1984年   1篇
  1982年   1篇
  1974年   2篇
  1973年   2篇
  1971年   1篇
  1966年   1篇
  1960年   1篇
排序方式: 共有3247条查询结果,搜索用时 0 毫秒
81.
Hb Adana (HBA2: c.179G>A) is found worldwide but is extremely rare and carriers are asymptomatic, with red cell indices similar to α+-thalassemia (α+-thal) carriers. First line screening tests are unable to detect the unstable hemoglobin (Hb). Coinheritance with the α-thal (–α3.7) deletion is herein presented and the challenges involving genetic counseling of couples carrying the mutations are discussed.  相似文献   
82.
Single-incision approach in robotic gynecology is a relatively new concept. The role of single-port systems in robotic hysterectomy, their advantages and disadvantages, as well as the technical challenges, are still under investigation. A systematic review was performed by searching in PubMed and Scopus databases. In 810 out of 1225 patients, hysterectomy was performed for non-neoplastic disease. Single-Site® was the most common port system. Duration of the procedure and relative blood loss ranged from 60 to 311 min and 7 to 750 ml, respectively. The weight of the removed uteri ranged from 39 to 520 g. 4.9% of the included patients presented complications, among which bleeding, vaginal haematoma, laceration and dehiscence, umbilical hernia, and visceral injuries. Conversion rate to laparotomy reached 2.8%. Although some technical difficulties are still described in the literature, the single-port approach is becoming more standardized nowadays and performed by more surgeons. The initial phase of the learning curve can be achieved after five cases, while a proficiency in intracorporeal cuff suturing after 14 cases. Uterus weight and previous abdominal surgical history can still be limitations of the technique. Compared to our previous study, we can see that the technique has been used in more elderly or obese patients. The complication rate can reach 4.9% while the conversion rate can reach 2.8%. However, we consider that complication and conversion rates as well as surgical time could be improved with experience. Regarding post-operative pain and cosmetic outcomes, the lack of information do not allow us to draw any safe conclusions.  相似文献   
83.
The growing role of targeted medicine has led to an increased focus on the development of actionable biomarkers. Current penalized selection methods that are used to identify biomarker panels for classification in high-dimensional data, however, often result in highly complex panels that need careful pruning for practical use. In the framework of regularization methods, a penalty that is a weighted sum of the L1 and L0 norm has been proposed to account for the complexity of the resulting model. In practice, the limitation of this penalty is that the objective function is non-convex, non-smooth, the optimization is computationally intensive and the application to high-dimensional settings is challenging. In this paper, we propose a stepwise forward variable selection method which combines the L0 with L1 or L2 norms. The penalized likelihood criterion that is used in the stepwise selection procedure results in more parsimonious models, keeping only the most relevant features. Simulation results and a real application show that our approach exhibits a comparable performance with common selection methods with respect to the prediction performance while minimizing the number of variables in the selected model resulting in a more parsimonious model as desired.  相似文献   
84.
85.
Journal für Ästhetische Chirurgie - Fett bietet neben seinem volumisierenden Effekt ein reichhaltiges Reservoir für regenerative Zellen, die eine wichtige Rolle für den Einbau...  相似文献   
86.
87.
The long-term findings on brain magnetic resonance imaging (MRI) in a 7 10/12-year-old boy with a history of acute encephalopathy with bilateral striatal necrosis following measles at the age of 22 months are described. At the early stage of illness, brain MRI studies revealed bilateral, symmetric basal ganglia lesions, predominant on the globi pallidi, appearing as hyperintense signals on T1- and T2-weighted images. Six years later, follow-up brain MRI studies showed that the bilateral, symmetric lesions on the globi pallidi persisted with low signal on T1- and high signal on T2 weighted images. At present, the patient has some persistent neurologic signs. These findings suggest that both clinical and neuroradiologic findings may persist in children with acute encephalopathy with bilateral striatal necrosis following measles.  相似文献   
88.
89.
A recently developed immunocytochemical technique in HbF-cell counting was assessed by an objective evaluation method. The basic principle of this method is the preparation of aliquots with predetermined HbF-cell (target) values. These aliquots serve as control samples to standardize the HbF-cell measurements by the new immunocytochemical technique, which uses the StreptABComplex/AP staining procedure (SAP) and visualization under white light. Immunofluorescence optical counts (IF) were performed in parallel with the new technique. A trend of inaccuracy was observed in low target values for both methods. As the level of target values increased, deviations became insignificant (relative accuracy < 8%) with SAP having slightly better results. Linear regression data of the estimated %HbF-cell rates by the two methods versus the target values were very satisfactory for both methods with SAP being slightly better. SAP seems to provide an accurate and reliable alternative for HbF-cell estimation comparable with the classical IF optical count.  相似文献   
90.
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