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   10079篇
  免费   647篇
  国内免费   196篇
耳鼻咽喉   441篇
儿科学   227篇
妇产科学   70篇
基础医学   1299篇
口腔科学   194篇
临床医学   1225篇
内科学   870篇
皮肤病学   99篇
神经病学   2521篇
特种医学   213篇
外科学   1430篇
综合类   750篇
现状与发展   1篇
预防医学   562篇
眼科学   212篇
药学   557篇
  5篇
中国医学   170篇
肿瘤学   76篇
  2024年   14篇
  2023年   137篇
  2022年   214篇
  2021年   353篇
  2020年   310篇
  2019年   303篇
  2018年   312篇
  2017年   333篇
  2016年   282篇
  2015年   268篇
  2014年   457篇
  2013年   670篇
  2012年   387篇
  2011年   505篇
  2010年   413篇
  2009年   439篇
  2008年   445篇
  2007年   462篇
  2006年   397篇
  2005年   329篇
  2004年   337篇
  2003年   303篇
  2002年   266篇
  2001年   207篇
  2000年   168篇
  1999年   151篇
  1998年   206篇
  1997年   184篇
  1996年   155篇
  1995年   148篇
  1994年   132篇
  1993年   146篇
  1992年   122篇
  1991年   141篇
  1990年   127篇
  1989年   102篇
  1988年   88篇
  1987年   80篇
  1986年   108篇
  1985年   155篇
  1984年   137篇
  1983年   108篇
  1982年   86篇
  1981年   53篇
  1980年   44篇
  1979年   34篇
  1978年   29篇
  1977年   17篇
  1976年   17篇
  1974年   13篇
排序方式: 共有10000条查询结果,搜索用时 9 毫秒
11.
孙宁玲 《世界临床药物》2009,30(10):577-580
高血压高危患者的降压治疗既需降低血压,又需保持足够血流以保障器官灌注。血压降低过度无疑也有一定风险,因此控制皿压需要底线。高危高血压患者的个体差异大,在降压治疗过程中,临床医生既要以循证医学为鉴,叉须遵循个体化治疗原则,把握好降压幅度和速度,坚持高质量平稳降压,才能更好地保护靶器官,减少心脑血管意外的发生。  相似文献   
12.
OBJECTIVES: We analyzed the methods and outcomes of urethroplasty in men with complex urethral disruptions. METHODS: The medical records of 40 men with complex urethral disruptions were analyzed. Surgical methods were individualized according to stricture location, severity and length of the stricture, bladder neck characteristics and presence of complicating factors. Patients were divided into four groups based on the above characteristics. RESULTS: End-to-end urethroplasty performed in six patients with short bulbar strictures (<3 cm) was successful in all. Elaborated perineal repair was performed in 10 patients with intermediate (3-6 cm) strictures with or without complicating factors. Elaborated perineal repair with urethral substitution was performed in nine patients with long segment stricture (>6 cm). Abdominal transpubic repair was successfully applied to patients with rectourethral fistula or lacerated bladder neck. Success rate of anastomotic urethroplasty was 95% while over all success rate was 85%. CONCLUSION: Guidelines for urethral reconstruction of complex urethral disruptions are predicated on stricture length, location, bladder neck characteristics and associated complicating factors. End-to-end urethroplasty with stricture excision is highly reliable for short strictures for which previous operative repair have failed. Elaborated perineal repair is extremely versatile for intermediate and longer strictures with associated complicating factors. Abdominal transpubic urethroplasty is effective for patients with rectourethral fistula or lacerated bladder neck.  相似文献   
13.
45 patients with spinocerebellar degeneration (SCD) underwent through quantitative investigation of the ventricular and cisternal systems by CT scanning and threshold vibrometry in the limbs to find out whether these parameters could be used for distinguishing mainly spinal from cerebellar forms or from olivopontoce-rebellar atrophy. The increase in the vibration sense threshold and the mild atrophy in the posterior cranial fossa proved typical of spinal forms and the reverse for cerebellar forms. In olivopontocerebellar atrophy enlargement of the cisterns and dilatation of the ventricles always exceeded 85% of normal values.
Sommario 45 pazienti affetti da degenerazione spinocerebellare (SCD) sono stati sottoposti ad uno studio approfondito di esplorazione quantitativa del sistema ventricolare e cisternale alla TAC e della soglia di percezione vibratoria agli arti per valutare la possibilità di distinguere con questi parametri le forme prevalentemente spinali da quelle cerebellari o delle atrofie olivopontocerebellari. L'aumento della soglia vibratoria e la modesta atrofia in fossa posteriore è risultata tipica delle forme spinali, mentre l'inverso si verifica per le forme cerebellari. Nelle atrofie olivopontocerebellari l'allargamento delle cisterne e la dilatazione dei ventricoli supera quasi sempre l'85% rispetto ai casi normali.
  相似文献   
14.
We have developed a guar wholemeal bread and tested its physiological efficacy and sensory qualities. The objective of the study was to estimate the optimum concentration of guar in bread required to reduce postprandial glycaemia and insulinaemia without adversely affecting the quality of the bread. Following overnight fasts, 15 normal weight, non-diabetic subjects consumed meals of wholemeal bread alone (controls) and supplemented with guar at three different concentrations (5, 10 and 15% replacement of wheat flour). Blood samples for glucose and insulin analysis were taken preprandially, and at 30 and 60 min after the start of each meal. The acceptability of the wholemeal control and guar breads was assessed using a hedonic scaling method. A significantly lower blood glucose rise at 30 min was found after the 15% guar bread meal compared to the control. Plasma insulin responses at 30 and 60 min were significantly lower after the 10 and 15% guar bread meals compared to the controls. Hedonic scores indicated that the subjects found the 5 and 10% guar breads acceptable and in the case of the 5% variety the mean score was identical to the control. We suggest that a guar concentration of between 5 and 10% replacement of wheat flour (wholemeal or white) should be used for the baking of guar wholemeal bread but further work is needed to define the precise quantity of guar required.  相似文献   
15.
Infants living in an orphanage (n = 22) in Romania were assessed on the Test of Sensory Functions in Infants (TSFI). Testing of the institutionalized infants was done before and 6 months after an enriched caregiver intervention program. Results showed significant changes in areas of reactivity to tactile deep pressure, visual-tactile integration, oculomotor control, reactivity to vestibular stimulation and total test responses. No significant changes occurred in the area of adaptive motor functions. Effects of sensory deprivation resulting from institutional settings and changes that can occur from enriched caregiver environments are discussed.  相似文献   
16.
5-羟色胺对大鼠脊髓P物质痛觉调制的影响(英文)   总被引:1,自引:0,他引:1  
比较SP,5-HT与For诱发的脊髓内c-fos表达的异同,以及它们之间的相互关系,从而进一步了解SP在脊髓痛觉调制中的主要作用.方法:用免疫组织化学法和痛阈测定法.结果:发现大鼠it P物质(sP)10μg和sc5%甲醛(For)150μL诱发的脊髓c-fos表达主要在背角Ⅰ,Ⅱ,Ⅴ及Ⅵ层,同时SP使痛阈降低,For使痛级均数(PIR)升高.5-HT it 20μg引起的c-fos表达较多地分布于背角Ⅲ—Ⅳ层,并可使痛阈升高.5-HT和Fen可分别减弱和增加SP及For诱发的脊髓c-fos表达及痛反应.结论:SP在脊髓内可能主要起致痛作用,5-HT可抑制SP引起的脊髓c-fos表达,从而参与SP的痛觉调制作用.  相似文献   
17.
Abstract Several methods have been used to predict successful weaning and extubation among chronic obstructive pulmonary disease (COPD) patients. The objective of this study is to determine whether carbon dioxide recruitment threshold (PCO2RT) can be used as adjunct to conventional weaning parameters to predict early weaning and successful extubation. Twelve COPD patients who were ready to be extubated based on conventional weaning parameters were divided into group A ( n = 7) and group B ( n = 5). Group A were those patients with better weaning parameters and hence a higher probability of successful extubation as compared to group B. Carbon dioxide apnoeic threshold (PCO2AT) was obtained by hyperventilating the patient using an increment of two breaths per min until apnoea occurs. At this point, the PCO2AT or the PaCO2 during said apnoeic period was recorded. A dead space of 150 cc is then added to the circuit until the patient starts to breathe as evidenced by the sensitivity trigger indicator. The PCO2 obtained at this period is termed PCO2RT. After weaning for 30 min on a T-tube, another arterial blood gas is determined and this is called the PCO2SB or the CO2 level after 30 min on spontaneous breathing. If the PCO2SB-PCO2RT difference is high with a sensitivity of 85.71% and specificity of 100% vs sensitivity of 57.14% and specificity of 60% using the conventional weaning parameters. Thus an increase in PCO2SB at 30 min T-tube is indicative of impending respiratory pump failure and that other causes of failure to wean must be investigated.  相似文献   
18.
Background Interleukin-8 (IL-8) hus been shown to be a chemotactic factor for netitrophils, T-lymphocytes and eosinophils. Repeated intranasal administration of IL-8 enhances bronchial responsiveness to inhaled histamine in guinea-pigs. Neuropeptides which arc released trotn C-fibre nerve-endings have been postulated to induce bronchial hyperresponsiveness through neurogenic inflammation. Objective This study was conducted to examine whether sensory neuropeptides are involved in the IL-8-induced bronchial hyperresponsiveness. Methods IL-8 at a dose of 5μg/kg was administered intranasally to guinea-pigs twice a week for 3 weeks. One day after the last administration, animals were anesthetized and artificially ventilaled through tracheal cannula, and lateral pressure at the tracheal cannula (Pao) was measured as an overall index of airway responses lo increasing concentrations of inhaled histamine (25, 50, 100, and 200 μg/mL). A NKI and NK2 dual antagonist FK224(10mg/kg), a selective NK1 antgonist FK888 (10mg/kg) or vehicle was intravenously administered 10min before measurement of bronchial responsiveness. Result The IL-8 treatment significantly enhanced bronchial responsiveness to histamine (ANOVA P < 0.01). FK224 or FK888 did not alter the IL-8-induced bronchial hyperresponsiveness. Conclusion We conclude that repeated intranasal administratioti of IL-8 causes bronchial hyperresponsiveness (BHR) and that neuropeptides such as neurokinin A and substance P do not directly contribute to the development of BHR induced by IL-8.  相似文献   
19.
在海拔3417m对18名健康世居藏族和16名移居汉族用Jeager气体代谢自动分析系统和心阴抗图测定了无氧阈和最大摄氧量时的SV、CO、PEP/LVET和SaO2。结果显示:在海拔3417m测得AT值明显低于海平面;世居藏族AT出现较晚,并且AT时的功率、VO2、MV、HR、CO、SV均高于移居汉族,而PET/LVET比值小于移居组;两组的SV峰值出现时间不同,蕊居组在AT或AT以后出现的占72%  相似文献   
20.
Geste antagonistes, or sensory tricks, are well described in focal dystonia affecting the neck, hand, and face. Improvement in dystonic movements is typically maintained while the trick is performed, but disappears when the geste ends. We investigated the phenomenological features of geste antagoniste maneuvers in 19 patients with idiopathic lower cranial dystonia who were prospectively evaluated over a period of 6 years. Of the 19, 10 were men, mean age of onset was 49.8 years, and the most commonly involved lower cranial area was the jaw (10 patients). In most patients, dystonia was task-specific. Taking advantage of the improvement with a sensory geste, we manufactured oral appliances that mimicked the geste in 8 patients, and 3 continue to use it.  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