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   22016篇
  免费   2585篇
  国内免费   825篇
耳鼻咽喉   162篇
儿科学   72篇
妇产科学   2094篇
基础医学   2411篇
口腔科学   338篇
临床医学   2301篇
内科学   1044篇
皮肤病学   68篇
神经病学   1573篇
特种医学   640篇
外国民族医学   24篇
外科学   2777篇
综合类   4117篇
现状与发展   8篇
预防医学   1158篇
眼科学   80篇
药学   1327篇
  21篇
中国医学   1417篇
肿瘤学   3794篇
  2024年   57篇
  2023年   310篇
  2022年   641篇
  2021年   889篇
  2020年   817篇
  2019年   655篇
  2018年   600篇
  2017年   916篇
  2016年   1008篇
  2015年   991篇
  2014年   1808篇
  2013年   1535篇
  2012年   1455篇
  2011年   1575篇
  2010年   1286篇
  2009年   1097篇
  2008年   1018篇
  2007年   1101篇
  2006年   1003篇
  2005年   759篇
  2004年   651篇
  2003年   649篇
  2002年   491篇
  2001年   463篇
  2000年   323篇
  1999年   297篇
  1998年   286篇
  1997年   271篇
  1996年   276篇
  1995年   253篇
  1994年   200篇
  1993年   169篇
  1992年   154篇
  1991年   143篇
  1990年   119篇
  1989年   124篇
  1988年   120篇
  1987年   99篇
  1986年   109篇
  1985年   137篇
  1984年   107篇
  1983年   96篇
  1982年   104篇
  1981年   83篇
  1980年   65篇
  1979年   35篇
  1978年   27篇
  1977年   15篇
  1976年   13篇
  1973年   8篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
951.
Abstract

Background/Objective: To test the hypothesis that apolipoprotein E (APOE) polymorphisms are associated with outcomes after spinal cord injury (SCI).

Methods: Retrospective cohort study, from rehabilitation admission to discharge.

Participants: Convenience sample of 89 persons with cervical SCI (C3-C8) treated from 1995 through 2003. Median age was 30 years (range 14-70); 67 were male (75%) and 83 were white (93%).

Main Outcome Measures: American Spinal Injury Association (ASIA) motor and sensory scores, ASIA Impairment Scale (AIS), time from injury to rehabilitation admission, and length of stay (LOS) in rehabilitation.

Results: Subjects with an APOE s4 allele (n = 15; 17%) had significantly less motor recovery during rehabilitation than did individuals without an s4 allele (median 3.0 vs 5.5; P < 0.05) and a longer rehabilitation LOS (median 106 vs 89 days; P = 0.04), but better sensory-pinprick recovery (median 5.0 vs 2.0; P = 0.03). There were no significant differences by APOE s4 allele status in sensory-light touch recovery, likelihood of improving AIS Grade, or time from injury to rehabilitation admission.

Conclusions: APOE ε4 allele was associated with differences in neurological recovery and longer rehabilitation LOS. Genetic factors may be among the determinants of outcome after SCI and warrant further study.  相似文献   
952.
953.
The involvement of the sympathetic nervous system in chronic pain conditions has been well described and recognized for over a century. However, the exact mechanism of the relationship has not been fully explained. In certain chronic pain conditions (e.g. complex regional pain syndrome (CRPS)), the presence of sympathetic signs forms part of the diagnostic criteria.  相似文献   
954.
Background/Objective: High cervical spinal cord hemisection interrupts descending respiratory drive from the rostral ventral respiratory group in the medulla to the ipsilateral phrenic motoneurons. Hemisection results in the paralysis of the ipsilateral hemidiaphragm. Chronic administration of rolipram, a specific phosphodiesterase-IV inhibitor, promotes synaptic plasticity and restores phrenic nerve function after a high cervical spinal cord lesion. Here, we test the hypothesis that an acute administration of rolipram will increase spinal and medullary levels of 3′,5′-cyclic adenosine monophosphate (cAMP) and induce phrenic nerve recovery after cervical (C2) spinal cord hemisection.

Methods: Male Sprague-Dawley rats were subjected to left C2 hemisection surgery 1 week before experimentation. Bilateral phrenic nerve activity was recorded in anesthetized, vagotomized, and pancuronium paralyzed rats, and rolipram was intravenously applied (2 mg/kg).

Results: Intravenous administration of rolipram increased phrenic nerve output in uninjured control and left C2 spinal cord-hemisected rats. In addition, rolipram restored respiratory-related activity to the left phrenic nerve made quiescent by the hemisection. In both uninjured and hemisected rats, rolipram significantly enhanced phrenic inspiratory burst amplitude and burst area compared with predrug values. Also, rolipram concomitantly increased spinal and medullary cAMP.

Conclusions: These results suggest that a phosphodiesterase inhibitor capable of elevating cAMP levels can enhance phrenic nerve output and restore respiratory-related phrenic nerve function after high cervical spinal cord injury. Thus, targeting the cAMP signaling cascade can be a useful therapeutic approach in promoting synaptic efficacy and respiratory recovery after cervical spinal cord injury.  相似文献   
955.
Abstract

Background: Diagnosing patients with cervical cord compressive myelopathy in a timely manner can be challenging due to varying clinical presentations, the absence of pathognomonic findings, and symptoms that are usually insidious in nature.

Objective: To describe the clinical course of a patient with primary complaint of left medial knee pain that was nonresponsive to surgical and conservative measures; the patient was subsequently diagnosed with cervical cord compressive myelopathy.

Design: Case report.

Subject: A 63-year-old man with a primary complaint of left medial knee pain.

Findings: Physical examination of the left knee was normal except for slight palpable tenderness over the medial joint line. During treatment, he noted loss of balance during activities of daily living. Reassessment revealed bilateral upper extremity hyperreflexia, bilateral Babinski reflex, and positive bilateral Hoffman reflex. Magnetic resonance imaging of the cervical spine demonstrated moderately severe spinal stenosis at the C3-C4, C5-C6, and C6-C7 levels. After C3-C7 laminoplasty for cervical cord compressive myelopathy, he reported substantial improvement of his left medial knee. Three years later, he had no complaint of knee pain.

Conclusion: Appropriate diagnosis and treatment of cervical cord compressive myelopathy may avoid unnecessary diagnostic imaging, medical evaluations, invasive procedures, and potential neurologic complications.  相似文献   
956.
957.
Ultrasound is a particularly valuable imaging technique when performing nerve blocks at the cervical level. High-frequency probes provide high-quality resolution and are safe in skilled hands. Typically, interventions performed at the cervical level have been carried out with the help of x-rays, with the corresponding disadvantages such as the exposure to radiation and the inherent inability to observe radiotransparent structures such as blood vessels and nerves. Ultrasound allows us to visualize soft tissues and guide the tip of the needle to our target, without harming particularly delicate structures found in the path of the needle. This is important in nerve root blocks where the identification of periradicular nerves is crucial for the safety of the block itself. Likewise, ultrasound allows us to manipulate the needle with greater precision in the correct location; as is the case in cervical sympathetic nerve block where we can observe the injection of the liquid behind the prevertebral fascia and in front of the fascia of the longus colli muscle. In this article, we describe the most frequent techniques used in the pain clinic to treat headache and cervical pain, with special emphasis on the safety of the procedure.  相似文献   
958.
目的评价前路选择性间隙减压融合术治疗65岁以上老年多节段颈椎病的临床疗效。方法回顾性分析有完整随访资料的35例手术患者,根据症状、体征及影像学结果行选择性间隙减压植骨融合内固定术。采用日本骨科学会(Japanese Orthopaedic Association,JOA)评分和Odom标准进行临床疗效评定。结果手术时间为(86.5±27.1)min,术中出血量为(95.7±42.9)mL。术前JOA评分为(8.4±2.6)分,末次随访时为(13.1±1.7)分,改莳率平均为58.7%,Odom优良率为82.4%。末次随访时均获骨性融合,内固定位置良好。结论术前充分准备,准确评估.正确选择减压节段,前路选择性间隙减压融合术是治疗老年多节段颈椎病的一种安全有效的手术方式:  相似文献   
959.
目的:探讨前路减压植骨内固定联合等离子髓核成形术治疗多节段受累颈椎病的临床效果。方法回顾性分析2012年3月至12月中山市人民医院采用前路减压植骨内固定结合等离子髓核成形术治疗的30例多节段受累颈椎病患者的临床资料,采用日本骨科学会(JOA)评分对术后临床症状改善情况进行评价。结果30例患者均获得有效随访,随访时间4~9个月(平均6.8个月)。患者术前不适症状均有不同程度改善,无神经功能加重及内固定松动、骨笼脱出等严重并发症发生。术后3个月JOA评分为(14±1)分,较术前的(10±2)分明显改善(t =8.143,P=0.000),JOA改善率为45%。结论前路减压植骨内固定结合等离子髓核成形术治疗多节段受累颈椎病近期效果稳定,并发症少。  相似文献   
960.
《Acta orthopaedica》2013,84(1-6):79-84
Fractures of the cervical spine in six patients suffering from ankylosing spondylitis are presented. Three patients had a hyperextension type of injury. These fractures were extremely unstable and combined with spinal cord damage. in the other cases the fracture was caused by a flexion mechanism. These fractures were stable and there was no damage to the spinal cord. Treatment modified according to the demands of the fractures is outlined.  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