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   88857篇
  免费   7892篇
  国内免费   4210篇
耳鼻咽喉   1242篇
儿科学   1777篇
妇产科学   651篇
基础医学   6263篇
口腔科学   1367篇
临床医学   12893篇
内科学   7901篇
皮肤病学   432篇
神经病学   8008篇
特种医学   5303篇
外国民族医学   3篇
外科学   18553篇
综合类   16329篇
现状与发展   4篇
一般理论   1篇
预防医学   5053篇
眼科学   1314篇
药学   7435篇
  71篇
中国医学   4009篇
肿瘤学   2350篇
  2024年   258篇
  2023年   1582篇
  2022年   2930篇
  2021年   4417篇
  2020年   4094篇
  2019年   3104篇
  2018年   3028篇
  2017年   3425篇
  2016年   3637篇
  2015年   3396篇
  2014年   5909篇
  2013年   6908篇
  2012年   5516篇
  2011年   5965篇
  2010年   4985篇
  2009年   4743篇
  2008年   4578篇
  2007年   4579篇
  2006年   4269篇
  2005年   3783篇
  2004年   3155篇
  2003年   2897篇
  2002年   2183篇
  2001年   1948篇
  2000年   1594篇
  1999年   1264篇
  1998年   1116篇
  1997年   960篇
  1996年   796篇
  1995年   659篇
  1994年   506篇
  1993年   420篇
  1992年   366篇
  1991年   264篇
  1990年   227篇
  1989年   216篇
  1988年   159篇
  1987年   156篇
  1986年   133篇
  1985年   180篇
  1984年   121篇
  1983年   74篇
  1982年   97篇
  1981年   88篇
  1980年   83篇
  1979年   54篇
  1978年   34篇
  1977年   35篇
  1976年   28篇
  1975年   13篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
A local pedicled vascularized bone flap can prevent the morbidity and cost of free bone flap surgery in small segmental bone defects or long cartilaginous defects of the head and neck. Such flaps can also be useful in patients who are high risk for surgery. The periosteal vascularity of the mandible can be used to design islanded facial artery-based bone flaps, which can be utilized to that extent. Two patients with a small segmental mandibulectomy defect and one patient with a long cricotracheal resection defect underwent reconstruction using three different designs of islanded facial artery osteomyomucosal/osseous flap (iFOMM). The patients had a minimum follow-up period of 18 months. All flaps were successful, with satisfactory healing and without any functional deficit or disease at last follow-up.  相似文献   
52.

Background

Current blunt cerebrovascular injury (BCVI) grading grossly differentiates injury characteristics such as luminal stenosis (LS) and aneurysmal disease. The effect of increasing degree of LS beyond the current BCVI grading scale on stroke formation is unknown.

Study Design

BCVI over a 3-year period were retrospectively reviewed. To investigate influence of LS beyond the BCVI grading scale within aneurysmal and non-aneurysmal BCVI, grade 2 BCVI were subdivided into BCVI with ≥ 25% and ≤ 50% LS and BCVI with > 50% and ≤ 99% LS. Grade 3 BCVI were subdivided into BCVI with pseudoaneurysm (PSA) without LS and BCVI with PSA and LS. We hypothesized increased LS beyond the current BCVI grade distinctions would be associated with higher rates of stroke formation.

Results

312 BCVI were included, of which 140 were carotid BCVI and 172 vertebral BCVI. Sixteen carotid BCVI underwent endovascular intervention (EI) and 19 suffered a stroke. In carotid BCVI stroke rates increased sequentially with BCVI grade except in grade 3. There was a stroke rate of 12% in grade 1 carotid BCVI, 18% in grade 2, 6% in grade 3, and 31% in grade 4. In subgroup analysis for grade 2 carotid BCVI, BCVI with > 50% and ≤ 99% LS had higher rates of stroke (22% vs. 15%, p?=?0.44) than BCVI with ≥ 25% and ≤ 50% LS. In subgroup analysis of grade 3 carotid BCVI, BCVI with PSA and LS had higher rates of stroke (9% vs. 4%, p?=?0.48) than BCVI with PSA without LS. Higher rates of EI in grade 2 carotid BCVI with > 50% and ≤ 99% LS (22% vs. 5%, p?=?0.14) and grade 3 carotid BCVI with PSA and LS (35% vs. 4%, p?=?0.01) were noted in subgroup analysis.

Conclusion

Higher percentage LS beyond the currently used BCVI grading scale has a non-significantly increased rate of stroke in both aneurysmal and non-aneurysmal BCVI. Grade 3 BCVI with PSA and LS seems to be a high-risk subgroup. Use of EI confounds modern measurement of stroke risk in higher LS BCVI.  相似文献   
53.
54.
55.
<正>机体的血钾参与并维持细胞代谢,保持细胞内液渗透压及酸碱平衡,并可维持神经肌肉组织兴奋及心肌功能~([1-2])。中重度低血钾主要表现为肌无力,可延及机体的躯干和呼吸肌,造成呼吸困难,还可引发腱反射减弱或消失、肠麻痹及心脏传导阻滞、节律异  相似文献   
56.
PurposeType B aortic dissection is a rare but life-threatening disease. Thoracic endovascular aortic repair (TEVAR) was widely used for Type B aortic dissection patients in the last decade due to the lower mortality and morbidity compared with open chest surgical repair (OCSR). AKI in type B aortic dissection is a well-recognized complication and indicates poor short-term and long-term outcome. The objective of this concise review was to identify the risk factors and the impact of AKI on type B aortic dissection patients.Methods and resultsA literature search was performed using PubMed, Embase, MEDLINE, and Cochrane Library with the search terms ‘type B aortic dissection’ and ‘acute kidney injury’ (AKI), and all English-language literatures published in print or available online from inception through August 2020 were thoroughly reviewed. Studies that reported relative AKI risks and outcomes in type B aortic dissection patient were included. Major mechanisms of AKI in type B aortic dissection included renal hypoperfusion, inflammation response, and the use of contrast medium. Type B aortic dissection patients with AKI significantly had increased hospital stay duration, need of renal replacement therapy, and 30-d and 1-year mortality.ConclusionsAKI in type B aortic dissection is a well-recognized complication and associated with poor short-term and long-term outcome. Early identification of high-risk patients, early diagnosis of AKI, stabilization of the hemodynamic parameters, avoidance of nephrotoxic drugs, and optimization of the use of contrast agents are the major strategies for the reduction of AKI in type B aortic dissection patients.  相似文献   
57.
58.
Radial neck fractures account for 1% of all paediatric fractures and constitute 5–10% of elbow injuries. Radial neck fractures rarely occur at age 2 or less. It is difficult to assess and reduce radial neck fractures in children with unossified radial head. We report a case of 2 years old female child presented to emergency with history of fall from stairs on an outstretched hand. Radiograph showed a metaphyseal spike in the proximal radius which prompted us to think of a radial neck fracture. Since the radial head was not ossified, the amount of displacement and angulation was not exactly quantifiable on radiographs only. Hence an arthrogram was planned. Intra operative use of radio opaque dye injection into elbow joint delineates the radial head and capitellum. It helps in identifying the fracture morphology and will also assist in reduction. We reduce radial head by K wire leverage technique and the intramedullary elastic titanium nail was added to assist in reduction and to improve fixation stability. We recommend arthrogram to be a safe and reliable option for proper assessment and reduction of radial neck fracture in an unossified radial head.  相似文献   
59.
Objective: To study the biomechanical mechanism of head injuries beaten with sticks, which is common in the battery or assaultive cases. Methods: In this study, the Hybrid-III anthropomorphic test device and finite element model (FEM) of the total human model for safety (THUMS) head were used to determine the biomechanical response of head while being beaten with different sticks. Total eight Hybrid-III tests and four finite element simulations were conducted. The contact force, resultant acceleration of head center of gravity, intracranial pressure and von Mises stress were calculated to determine the different biomechanical behavior of head with beaten by different sticks. Results: In Hybrid-III tests, the stick in each group demonstrated the similar kinematic behavior under the same loading condition. The peak values of the resultant acceleration for thick iron stick group, thin iron stick group, thick wooden stick group and thin wooden stick group were 203.4 g, 221.1 g, 170.5 g and 122.2 g respectively. In finite element simulations, positive intracranial pressure was initially observed in the frontal comparing with negative intracranial pressure in the contra-coup site. Subsequently the intracranial pressure in the coup site was decreasing toward negative value while the contra-coup intracranial pressure increasing toward positive values. Conclusions: The results illustrated that the stiffer and larger the stick was, the higher the von Mises stress, contact force and intracranial pressure were. We believed that the results in the Hybrid-III tests and THUMS head simulations for brain injury beaten with sticks could be reliable and useful for better understanding the injury mechanism.  相似文献   
60.
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