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   2472篇
  免费   302篇
  国内免费   108篇
耳鼻咽喉   97篇
儿科学   28篇
妇产科学   20篇
基础医学   275篇
口腔科学   235篇
临床医学   362篇
内科学   98篇
皮肤病学   6篇
神经病学   965篇
特种医学   125篇
外科学   292篇
综合类   175篇
预防医学   81篇
眼科学   8篇
药学   64篇
中国医学   45篇
肿瘤学   6篇
  2024年   9篇
  2023年   37篇
  2022年   57篇
  2021年   113篇
  2020年   110篇
  2019年   126篇
  2018年   126篇
  2017年   117篇
  2016年   91篇
  2015年   90篇
  2014年   139篇
  2013年   144篇
  2012年   126篇
  2011年   122篇
  2010年   90篇
  2009年   97篇
  2008年   105篇
  2007年   104篇
  2006年   114篇
  2005年   95篇
  2004年   87篇
  2003年   74篇
  2002年   62篇
  2001年   48篇
  2000年   35篇
  1999年   37篇
  1998年   60篇
  1997年   61篇
  1996年   53篇
  1995年   43篇
  1994年   47篇
  1993年   40篇
  1992年   36篇
  1991年   28篇
  1990年   24篇
  1989年   23篇
  1988年   11篇
  1987年   14篇
  1986年   14篇
  1985年   11篇
  1984年   9篇
  1983年   7篇
  1982年   11篇
  1981年   8篇
  1980年   8篇
  1979年   6篇
  1977年   4篇
  1976年   2篇
  1974年   2篇
  1970年   2篇
排序方式: 共有2882条查询结果,搜索用时 15 毫秒
81.
肛门和尿道括约肌肌电图对多系统萎缩(MSA)具有诊断和鉴别诊断价值。本文综述了两种检查方法的解剖及病理生理基础、方法学、正常和异常表现以及在神经系统疾病中的诊断及鉴别诊断价值。目前,两种检查方法对多系统萎缩诊断及鉴别诊断价值仍存在争议,对MSA诊断的特异性及敏感性,二者差异与临床特点的相关性,以及是否可以互相弥补尚未见报道。肛门和尿道括约肌肌电图在MSA时表现为神经源性损害的改变,在怀疑MSA时该项检查可作为常规的电生理检测手段,对于鉴别诊断以及两者之间的相互关系尚有进一步研究的空间。  相似文献   
82.

Purpose

The cervical flexion relaxation phenomenon (FRP) is a neck extensor myoelectric “silence” that occurs during complete cervical and lumbar flexion. In contrast to low back pain, the changes that occur during FRP in chronic neck pain (CNP) patients are still not clear. The aim of this study was to assess the characteristics of this phenomenon in the cervical region in CNP patients and controls.

Methods

Twenty-two women (23 ± 2.62 years) with chronic non-specific neck pain and 21 healthy women (23.4 ± 1.68 years) participated in this study. They accomplished a cervical flexion and extension from neutral position. Neck angle and surface electromyographic activity of cervical erector spinae (CES) and upper trapezius muscles were recorded. Appearance, onset and offset angle of the FRP were analysed and compared between the two groups.

Results

There were significant differences in the appearance of FRP between the two groups (P ≤ 0.001). The FRP in the CES muscles was observed in 85.7 % of healthy subjects and in 36.3 % of CNP patients, and no FRP was observed in the upper trapezius. Results of this study show that the onset and offset of FRP parameters were significantly different between the two groups (P ≤ 0.001).

Conclusions

The results of the present study indicate that FRP in CNP patients was seen less than the healthy subjects, and moreover the FRP period was reduced in CNP patients. Our results also suggest that the changes in FRP of CNP patients may be due to the increased CES activity in these patients.  相似文献   
83.
84.
85.
Haemodynamic and pulmonary functional data were recorded in 10 patients undergoing mitral valve replacement with the Björk—Shiley tilting disc valve. Within 48 hours after surgery, mean pulmonary capillary wedge pressure decreased from 27.9 mmHg pre-operatively to 14.3 mmHg, while mean pulmonary arterial pressure (PAP) remained elevated at 31.3 mmHg. Although the cardiac index rose to 2.9 1/min·m2, pulmonary vascular resistance (PVR) increased in the first 3 days. PAP and PVR had returned to normal at late control 6–10 months postoperatively. Vital capacity and forced expiratory volume in one second both showed a mean improvement of 15% at late control. Simple spirometry may be a valid indirect method of assessing easily and objectively the efficacy of mitral valve replacement.  相似文献   
86.
We evaluated the clinical outcome of tripled semitendinosus tendon ACL reconstruction with femoral Endobutton (Acufex, Smith&Nephew, Andover, MA) and tibial Suture Washer (Acufex, Smith&Nephew, Andover, MA) (n 29) or post screw fixation (n 6) in 35 patients on an average of 28 (20-37) months after surgery. On the basis of IKDC criteria, 22 patients showed a normal or nearly normal knee function and 25 patients had a KT 1000 maximal manual side-to-side difference of &#104 5 mm at follow-up. Subjectively, 28 patients graded their knee function as normal or nearly normal. The average Lysholm score was 88 points, average OAK score 90 points and average modified HSS score 93 points. 19 patients reached their preinjury level of activity at follow-up. The postoperative Lachman test was &#104 1+ in 24 patients and 24 patients also showed an absent pivot shift. Significant bone tunnel enlargement occurred in 26 patients on the femoral side and in 23 patients on the tibial side. We found no correlation between bone tunnel enlargement and clinical outcome. The clinical outcome of tripled semitendinosus tendon ACL reconstruction with Endobutton fixation on the femoral side was not entirely satisfactory. The procedure was associated with a high incidence of bone tunnel enlargement in this series.  相似文献   
87.
Introduction: We sought to determine whether electrical impedance myography (EIM) could serve as a diagnostic procedure for evaluation of radiculopathy. Methods: Twenty‐seven patients with clinically and radiologically diagnosed cervical or lumbosacral radiculopathy who met a “gold standard” definition underwent EIM and standard needle electromyography (EMG) of multiple upper or lower extremity muscles. Results: EIM reactance values revealed consistent reductions in the radiculopathy‐affected myotomal muscles as compared with those on the unaffected side; the degree of asymmetry was associated strongly with the degree of EMG abnormality (P < 0.001). EIM had a sensitivity of 64.5% and a specificity of 77.0%; in comparison, EMG had a sensitivity of 79.7% but a specificity of 69.7%. Conclusions: These findings support the potential for EIM to serve as a new non‐invasive tool to assist in diagnosis of radiculopathy; however, further refinement of the technique is needed for this specific application. Muscle Nerve 48:800–805, 2013  相似文献   
88.
Introduction: Repetitive discharges may be recorded during nerve conduction studies (NCS) or during needle electromyography in a muscle at rest. Repetitive discharges that occur during voluntary activation and are time‐locked to voluntary motor unit potentials (MUP) have not been described. Methods: Retrospective review of motor unit potential induced repetitive discharges (MIRDs) identified in the EMG laboratory. Characteristics of each MIRD, patient demographics, other EMG findings in the same muscle, and electrophysiological diagnosis were analyzed. Results: MIRDs were observed in 15 patients. The morphology and number of spikes and duration of MIRDs varied. The discharges fired at rates of 50–200 Hz . All but 2 patients had EMG findings of a chronic neurogenic disorder. Conclusions: MIRDs are rare iterative discharges time‐locked to a voluntary MUP. The pathophysiology of MIRDs is unclear, but their presence may indicate a chronic neurogenic process. Muscle Nerve 48 : 977–979, 2013  相似文献   
89.
90.
Introduction: Detection of denervation in muscles in the craniobulbar area is important to assure widespread lower motor neuron involvement in the diagnosis of amyotrophic lateral sclerosis (ALS). The value of spontaneous activity analysis in needle electromyography (EMG) of the tongue has been questioned in the recent literature. Methods: Spontaneous activity in the tongue and sternocleidomastoid (SCM) muscles was reviewed retrospectively in 17 ALS patients. Results: Needle EMG showed spontaneous activity in the tongue in 14 of 17 patients (82%) and in 6 patients of 17 (35%) in SCM. Spontaneous EMG activity in the tongue was found in patients with and without bulbar symptoms. Conclusions: Needle EMG is a valuable method for assessing clinical and subclinical involvement of the tongue in patients with bulbar and limb onset ALS. Adequate relaxation of the tongue is a prerequisite for proper spontaneous activity recording. Muscle Nerve, 48: 296–298, 2013  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