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   17928篇
  免费   2050篇
  国内免费   281篇
耳鼻咽喉   936篇
儿科学   275篇
妇产科学   69篇
基础医学   1348篇
口腔科学   652篇
临床医学   1855篇
内科学   484篇
皮肤病学   66篇
神经病学   684篇
特种医学   1089篇
外国民族医学   1篇
外科学   6330篇
综合类   2478篇
预防医学   593篇
眼科学   308篇
药学   872篇
  15篇
中国医学   527篇
肿瘤学   1677篇
  2024年   22篇
  2023年   319篇
  2022年   412篇
  2021年   639篇
  2020年   823篇
  2019年   753篇
  2018年   636篇
  2017年   708篇
  2016年   813篇
  2015年   785篇
  2014年   1216篇
  2013年   1330篇
  2012年   1108篇
  2011年   1135篇
  2010年   985篇
  2009年   999篇
  2008年   854篇
  2007年   843篇
  2006年   768篇
  2005年   744篇
  2004年   668篇
  2003年   538篇
  2002年   457篇
  2001年   435篇
  2000年   367篇
  1999年   239篇
  1998年   218篇
  1997年   196篇
  1996年   135篇
  1995年   135篇
  1994年   103篇
  1993年   106篇
  1992年   96篇
  1991年   82篇
  1990年   50篇
  1989年   78篇
  1988年   43篇
  1987年   47篇
  1986年   42篇
  1985年   60篇
  1984年   44篇
  1983年   28篇
  1982年   46篇
  1981年   35篇
  1980年   33篇
  1979年   22篇
  1978年   18篇
  1977年   19篇
  1976年   10篇
  1975年   6篇
排序方式: 共有10000条查询结果,搜索用时 125 毫秒
71.
IntroductionCaloric testing is the most frequently used test to assess peripheral vestibular function since the beginning of the 20th century. However, the video head impulse test, vHIT, has gained prominence in the field of neurotology, as it is a faster examination, easier to perform and less uncomfortable for the patient.ObjectiveTo compare, through systematic review and meta-analysis, the proportion of altered cases between vHIT tests and caloric testing in patients with chronic dizziness, in addition to assessing the sensitivity and specificity of vHIT, with caloric testing as the gold standard.MethodsThe literature search was carried out in the PubMed, Scopus, BVS-Bireme, Web of Science, Embase, Cochrane and ProQuest indexed databases, with no restrictions regarding the publication period. All articles that contained the results of the two tests were included in the evaluation of patients with dizziness. Two researchers independently conducted data selection and extraction from the studies, strictly following the inclusion and exclusion criteria defined in the research protocol. In case of disagreement during the selection, a discussion was carried out with a third evaluator.ResultsEleven of the 1293 initial articles met the eligibility criteria and were analyzed. 2670 patients were evaluated, of which 1112 (41.6%) were males and 1558 (58.4%) females, with a mean age of 51.6 years. The proportion of altered results in the vHIT was 21% (95%CI 9% –33%), and 55% in the caloric testing (95%CI 43% –67%).ConclusionThe vHIT does not substitute for caloric testing. The tests are complementary in assessing the patient with dizziness, as they describe the tonotopy of the ampullary crest at different frequency ranges of stimulation. In chronic cases, the vHIT has a low sensitivity and high diagnostic specificity in comparison to caloric testing.  相似文献   
72.
Introduction: Surgery in patients with head and neck cancers is frequently complicated by multiple stages of procedure that includes significant surgical removal of all or part of an organ with cancer, tissue reconstruction, and extensive neck dissection. Postoperative wound infections, termed ‘surgical site infections’ (SSIs) are a significant impediment to head-and-neck cancer surgery and recovery, and need to be addressed.

Areas covered: Approximately 10–45% of patients undergoing head-and-neck cancers surgery develop SSIs. SSIs can lead to delayed wound healing, increased morbidity and mortality as well as costs. Consequently, SSIs need to be avoided where possible, as even the surgery itself impacts on patients’ subsequent activities and their quality of life, which is exacerbated by SSIs. Several risk factors for SSIs need to be considered to reduce future rates, and care is also needed in the selection and duration of antibiotic prophylaxis.

Expert commentary: Head and neck surgeons should give personalized care especially to patients at high risk of SSIs. Such patients include those who have had chemoradiotherapy and need reconstructive surgery, and patients from lower and middle-income countries and from poorer communities in high income countries, who often have high levels of co-morbidity because of resource constraints.  相似文献   

73.
74.

Objectives

Improved fixation techniques with optional use of bone cements for implant augmentation have been developed to enhance stability and reduce complication rates after osteosynthesis of femoral neck fractures. This biomechanical study aimed to evaluate the effect of cement augmentation on implant anchorage and overall performance of screw-anchor fixation systems in unstable femoral neck fractures.

Methods

Ten pairs of human cadaveric femora were used to create standardized femoral neck fractures (Pauwels type 3 fractures; AO/OTA 31-B2) with comminution and were fixed by means of a rotationally stable screw-anchor (RoSA) system. The specimens were assigned pairwise to two groups and either augmented with PMMA-based cement (Group 1, augmented) or left without such augmentation (Group 2, control).Biomechanical testing, simulating physiological loading at four distinct load levels, was performed over 10.000 cycles for each level with the use of a multidimensional force-transducer system. Data was analysed by means of motion tracking.

Results

Stiffness, femoral head rotation, implant migration, femoral neck shortening, and failure load did not differ significantly between the two groups (p?≥?.10). For both groups, the main failure type was dislocation in the frontal plane with consecutive varus collapse). In the cement-augmented specimens, implant migration and femoral neck shortening were significantly dependent on bone mineral density (BMD), with higher values in osteoporotic bones. There was a correlation between failure load and BMD in cement-augmented specimens.

Conclusion

In screw-anchor fixation of unstable femoral neck fractures, bone-cement augmentation seems to show no additional advantages in regard to stiffness, rotational stability, implant migration, resistance to fracture displacement, femoral neck shortening or failure load.  相似文献   
75.
76.
77.
Head and neck squamous cell carcinoma (HNSCC) is the sixth most common malignancy worldwide, accounting for more than 550,000 cases and 380,000 deaths annually. The primary risk factors associated with HNSCC are tobacco use and alcohol consumption; nevertheless genetic predisposition and oncogenic viruses also play important roles in the development of these malignancies. The current treatments for HNSCC patients include surgery, chemotherapy, radiotherapy, and cetuximab, and combinations of these. However, these treatments are associated with significant toxicity, and many patients are either refractory to the treatment or relapse after a short period. Despite improvements in the treatment of patients with HNSCC, the clinical outcomes of those who have been treated with standard therapies have remained unchanged for over three decades and the 5-year overall survival rate in these patients remains around 40–50%. Therefore, more specific and less toxic therapies are needed in order to improve patient outcomes. The tumour microenvironment of HNSCC is immunosuppressive; therefore immunotherapy strategies that can overcome the immunosuppressive environment and produce long-term tumour immunosurveillance will have a significant therapeutic impact in these patients. This review focuses on the current immunological treatment options under investigation or available for clinical use in patients with HNSCC.  相似文献   
78.

Introduction

In this retrospective study we have analyzed a consecutive series of patients affected by isolated radial head Mason III fractures and treated with bone resection or prosthesis.

Patients and methods

This study includes 24 patients affected by fractures mentioned above and treated between July 2009 and November 2015.15 patients (average age 48 y.o.) have been treated with prosthesis. The remaining 9 (average age 573) have been treated with a capitellectomy instead.From a clinical point of view, we have evaluated the patients according to main performance indicators such as range of motion, pain, instability and Mayo Elbow Performance Score as parameters.

Results

We have found similar results in both group, with an average MEPS value of 95 in the prosthesis group and 966 in the radial head resection group.The range of motion was similar too: between 1,3° and 1203° in the first group and between 4,4° and 120° in the second one. No significant complication has detected in any patient.

Discussion

According to most recent literature, it is not precisely defined how to treat isolated Mason III fractures, contrary to what is defined in more complex pattern, in which prosthesis are now evaluated as the best indication.Due to radial head limited contribution to elbow stability, in absence of other bony or ligamentous lesions both capitellectomy and prosthesis can be good treatment in this kind of fracture.

Conclusion

According to our experience and to the most recent literature, we recommend prosthesis in patient younger than 50 y.o., high demanding or manual worker, while in other cases we think that radial head resection can be the treatment of choice.  相似文献   
79.
总结了全国著名骨伤专家梁铁民教授的学术思想和正骨经验,简述了梁老生平。梁老学术思想表现在突出整体观念,主张辨证施术;注重调理气血,强调药物接续;重视望问切触量法五诊结合等三个方面。对于梁老正骨经验先进行了综合论述,进一步佐证其学术思想;后分别从小儿桡骨头半脱位、颈椎错位、胸腰椎小关节错位、肋骨骨折等梁老研究较深入和比较擅长的几个方面进行了阐述。特别是颈椎错位这种高难度高风险的手法操作,体现出梁老高超的手法技艺。  相似文献   
80.

Introduction

In the United States there has been a large increase in participation in lacrosse for both males and females. The purpose of this study was to analyze the number of head injuries, injury rates (calculated using the reported number of participants) and types of head injuries that are seen in emergency departments in the United States.

Methods

We compared injuries between male and female lacrosse participants. This was a retrospective study using a publicly available database produced by the US Consumer Product Safety Commission and information about lacrosse participation from US Lacrosse.

Results

A linear regression was performed and showed a positive correlation between number of head injuries to males and time from 2002 to 2010 (R2?=?0.823; p?=?0.001). While the number of injuries to the head in female lacrosse participants was not significant. There was a negative correlation between the number of head injuries to males from 2010 to 2016 (R2?=?0.800; p?=?0.007), but again, there was no significance for female injury count (R2?=?0.417; p?=?0.117). Other significant differences between head injuries in males and females included the mechanism of injury and the type of injury recorded.

Conclusion

The most recent data from 2010 to 2016, suggest that both males and females have had a decrease in injury rate. However the total number of female head injuries is not significantly decreasing and as the sport continues to grow there will likely be more total head injuries and visits to the emergency department.  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