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   37317篇
  免费   2282篇
  国内免费   2101篇
耳鼻咽喉   463篇
儿科学   747篇
妇产科学   123篇
基础医学   2976篇
口腔科学   83篇
临床医学   5110篇
内科学   5021篇
皮肤病学   47篇
神经病学   5953篇
特种医学   2149篇
外国民族医学   1篇
外科学   8995篇
综合类   5783篇
现状与发展   5篇
预防医学   662篇
眼科学   258篇
药学   1500篇
  26篇
中国医学   1282篇
肿瘤学   516篇
  2024年   123篇
  2023年   660篇
  2022年   1009篇
  2021年   1467篇
  2020年   1498篇
  2019年   1224篇
  2018年   1232篇
  2017年   1186篇
  2016年   1270篇
  2015年   1295篇
  2014年   2448篇
  2013年   2597篇
  2012年   1940篇
  2011年   2102篇
  2010年   1805篇
  2009年   1688篇
  2008年   1627篇
  2007年   1820篇
  2006年   1623篇
  2005年   1435篇
  2004年   1186篇
  2003年   1187篇
  2002年   1029篇
  2001年   817篇
  2000年   726篇
  1999年   646篇
  1998年   626篇
  1997年   565篇
  1996年   477篇
  1995年   429篇
  1994年   395篇
  1993年   349篇
  1992年   344篇
  1991年   265篇
  1990年   258篇
  1989年   264篇
  1988年   192篇
  1987年   167篇
  1986年   216篇
  1985年   311篇
  1984年   261篇
  1983年   185篇
  1982年   204篇
  1981年   170篇
  1980年   151篇
  1979年   64篇
  1978年   60篇
  1977年   42篇
  1976年   22篇
  1975年   16篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
Naloxone, an opioid peptide antagonist, has been reported to facilitate voiding in neurologic bladder disorders, but its effects on the neural micturition reflex arc are poorly understood. We studied the effect of naloxone in 34 male adult cats, spinalized at C5-C6 level 7 to 119 days previously. Each cat served as its own control. The following tests were performed: Urethral pressure profiles, cystosphincterograms with the urethro-vesical junction opened and closed and mechanograms of the detrusor, and the circular and longitudinal urethral muscles. The study included (1) the effects of anesthesia of the bladder and pelvic nerve, as well as that of the urethral and pudendal nerves; (2) the action of naloxone; and (3) the action of oxymorphone. Our results demonstrated that naloxone (1) increased somatic (osteotendinous and nociceptive) reflexes and aggravated spasticity; (2) increased vegetative micturitional and sexual reflexes, in particular the urethra-urethral contraction reflex, aggravating the spasmodic contractions of the external sphincter; and (3) increased the frequency and intensity of the mass reflex. In consequence, we suggest that naloxone is contraindicated in cases of spinal cord lesions with detrusor-sphincter dyssynergia syndrome.  相似文献   
42.
腰椎全板减压术后顽固下腰痛的原因分析   总被引:6,自引:4,他引:2  
[目的]分析腰椎全板切除术后残留下腰痛的原因,指导选择合理的手术方法。[方法]回顾分析1996~2000年作者采用全椎板切除减压治疗的腰椎管狭窄症患者临床资料,69例获得5年以上随访的患者作为本组研究对象,使用日本骨科学会(JOA)标准对患者的神经功能和下腰痛程度进行评分,根据手术前后下腰痛程度的变化将病例分为无残存下腰痛(lowbackpain,LBP)组和残存LBP组,针对术前的临床和影像学参数,使用软件包SPSS13.0进行对数回归分析,确定术后残存下腰痛的临床预测因素,并对这些影响因素进行两组间比较和统计分析。[结果]术前腰椎前突角、腰椎活动度和手术减压范围与术后残存下腰痛密切相关。残存LBP组患者术前腰椎生理前突和活动度分别为(22.27°±3.12°)和(22.91°±2.31°),显著低于无残存LBP组患者的腰椎前突和活动度(37.23°±2.19°)和(31.66°±1.52°),P值分别为0.000和0.002;而残存LBP组的减压节段(2.77±0.19节)明显高于无残存LBP组(1.70±0.10节),P值为0.000。[结论]对于术前腰椎前突减小,腰椎活动度下降的椎管狭窄症患者单纯施行多节段的腰椎全板减压容易导致术后顽固性下腰痛的出现,应引起作者重视。  相似文献   
43.
Objective: Severe scoliosis refers to scoliosis with serious and stiff curve. It always combins with trunk imbalance in coronal and sagittal contour. Besides complex pathological changes, cardiopulmonary deficits and other concomitant diseases increase treatmental difficulties. So the treatment of severe scoliosis is always a great challenge to spine surgeon. Methods :Thirty-six patients with severe scoliosis received one stage posterior correction followed by anterior release during July 1997 to January 2003, including 9 males and 27 females. Mean age was 17.2 years. Of them, 33 was idiopathic scoliosis and 3 was neurofibromatosis scoliosis( Cobb angle: 85-116 degree); 20 cases were abnormal in sagital plane. Three-dimensional devised instrumentation were applied such as CD, CD-Horizon, TSRH or Isola in posterior procedure followed by anterior release during the same anesthesia. 31 cases of this group received thorac icplasty. Results: The correction in the frontal plane achieved an average of 48.5%. In the sagittal plane, the pathological shape of the spine was reduced and distinctly ameliorated. 80. 6% of the patients maintained or achieved balance of sagittal plane. There were no complications of severe neurological deficit, hook displacement, rod broken, and deep infection at follow-up. One case occurred traumatic pleurisy after operation and another appeared pseudarthrosis 2 years later. One case demonstrated imbalance 11 months after operation. One patient was presented loss of correction more than 10 degree at one year follow-up and 5.2 degree in average. Conclusion:The study indicates that the one stage posterior correction combined with anterior release in treatment of severe scoliosis can achieve satisfactory correction. Appropriate choice of cases, preoperational detailed assessment and application of SEP and wake-up test during operation can possibly reduce severe complication. The long-term outcomes still need further observation.  相似文献   
44.
【论文特点介绍】本研究观察了CRP是否可以作为肾动脉粥样硬化狭窄(ARAs)的独立危险因子。通过对危险因素进行多变量Logistic回归分析,结果表明年龄、冠脉病变严重程度、外周血管疾病是ARAS的独立危险因素,而CRP水平、高血压、高脂血症、肾功能不全并非ARAS的独立危险因素。  相似文献   
45.
AIMS: To assess the association between abnormal stress myocardial perfusion imaging (MPI) and cardiac events (CE) in asymptomatic patients with diabetes and with > or = 1 additional risk factor. Predictors of abnormal stress MPI were also evaluated. METHODS: Four hundred and forty-seven consecutive patients who underwent stress MPI were prospectively followed for 2.1 [0.5-4.1] years for the subsequent occurrence of hard CE (myocardial infarction and sudden or coronary death) and soft CE (unstable angina and ischaemic heart failure requiring hospitalization). Re-vascularization procedures performed as a result of the screening protocol were not included in the analysis. RESULTS: Follow-up was successful in 419 of 447 patients (94%), of whom 71 had abnormal MPI at baseline. Medical therapy was intensified in all subjects and especially in those with abnormal MPI. Twenty-three patients with abnormal MPI underwent a re-vascularization procedure. CEs occurred in 14 patients, including six of 71 patients (8.5%) with abnormal MPI and eight of 348 patients (2.3%) with normal MPI (P < 0.005). Only two patients developed a hard CE and 12 a soft CE. In multivariate analysis, abnormal MPI was the strongest predictor for CEs [odds ratio (OR) (95% CI) = 5.6 (1.7-18.5)]. Low-density lipoprotein cholesterol > or = 3.35 mmol/l [OR (95% CI) = 7.3; 1.5-34.7] and age > median [OR (95% CI) = 6.0 (1.2-28.6)] were additional independent predictors for CE. The independent predictors for abnormal MPI were male gender, plasma triglycerides > or = 1.70 mmol/l, creatinine clearance < 60 ml/min and HbA1c > 8%, with male gender the strongest [OR (95% CI) = 4.0 (1.8-8.8)]. CONCLUSIONS: Asymptomatic patients with diabetes in this study had a very low hard cardiac event rate over an intermediate period. This could be explained by the effects of intervention or by the low event rate in the background population. Randomized studies of cardiac heart disease screening are required in asymptomatic subjects with diabetes to determine the effectiveness of this intervention.  相似文献   
46.
We present a case of acute bowel obstruction in an immunocompromised child, who also had lobar pneumonia and a giant unilateral pneumatocele. She was successfully managed with subarachnoid anaesthesia for exploratory laparotomy to relieve a colonic obstruction. This proved to be a safe alternative to general anaesthesia with tracheal intubation in this patient and should be considered in infants and children in selected cases whenever a contraindication to general anaesthesia exists.  相似文献   
47.
Aims: Extra-adrenal paragliomas are neoplasms which have been the subject of much debate regarding parameters to establish their biological behaviour. This study describes the clinicopathological and immunohistochemical features of 30 cases of spinal paragliomas. Methods and results: There were 15 male and 15 female patients. The median age at diagnosis was 46 years (range 20–74 years). Fourteen patients presented with back pain, two with numbness of the lower extremities, one with difficulty in walking and one with spinal cord compression. Nineteen tumours were located in the lumbar region, six in the cauda equina, two in the filum terminale, two in the thoracic region and one in the cervical region. All patients underwent gross total excision. The size of the tumours ranged from 10 to 50 mm. Histologically, 18 neoplasms showed alveolar (Zellballen) pattern, seven a spindle component, two eosinophilic granular cells suggestive of oncocytic metaplasia, two melanin pigment and one ganglion cells. Positive immunohistochemical results include: neuron-specific enolase 23/23 (100%), synaptophysin 21/23 (91%), S100 protein 22/23 (95%, sustentacular cells), leu-enkephalin 11/23 (47%), somatostatin 8/23 (34%), focal glial fibrillary acidic protein 7/23 (30%), focal keratin 5/23 (21%), neurofilament proteins 3/23 (13%) and adrenocorticotrophic hormine (ACTH) 1/23 (4%). Follow-up information obtained in 20 patients show 17 patients alive over a period of 6–216 months. One patient had bone metastases. Two patients died of unrelated causes, including one of congestive heart failure and one of myocardial infarction. Conclusions: In our experience, spinal paragangliomas behave as slow-growing tumours susceptible to potential cure by total excision. We agree with the current World Health Organization (WHO) classification as grade I tumours. Less than 1% may be locally aggressive. Spinal paragangliomas immunoreact not only for conventional neuroendocrine markers but also for peptides including somatostatin and ACTH and focally for the epithelial marker keratin.  相似文献   
48.
49.
本组采用的扩大的椎板开窗术治疗腰椎间盘突出合并侧隐窝狭窄140例。结果全部优良,与适应症严格选择和手术损伤小有关。强调切除卡压神经根的侧隐窝后壁外侧,即上关节突的冠状面.不失其脊椎三柱系统的三角结构。俯卧位头低足高,可减少硬膜囊张力避免负损伤。切除棘突下椎板时,用神经拉勾代替神经剥离器易于分离黄韧带,用90度的椎板咬骨钳斜向棘突方向,可满意地切除该部份椎板黄韧带,并可刮切椎板内层。神经根周围滴入醋酸炎舒松A2-3ml,术后疼痛锐减。减压窗口置盖明胶海绵有其争议,作者实践体会放置害处不大,要求病人有“护腰”意识。  相似文献   
50.
Summary A case of a 31-year-old female with congenital esophageal stenosis presenting with symptoms of chest pain caused by esophageal dysmotility is described. The involved segment in congenital esophageal stenosis has a characteristic thickening of the muscularis propria layer, as seen by EUS examination. In these patients, symptoms of dysphagia can be managed with esophageal dilation and noncardiac esophageal chest pain responds to pharmacotherapy with diltiazem.The opinions and assertions contained herein are the private ones of the authors and are not to be construed as official policy or reflecting the views of the Army or the Department of Defense.  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