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   5378篇
  免费   458篇
  国内免费   155篇
耳鼻咽喉   10篇
儿科学   143篇
妇产科学   46篇
基础医学   439篇
口腔科学   23篇
临床医学   550篇
内科学   1055篇
皮肤病学   19篇
神经病学   822篇
特种医学   165篇
外科学   471篇
综合类   695篇
一般理论   1篇
预防医学   198篇
眼科学   32篇
药学   573篇
  5篇
中国医学   711篇
肿瘤学   33篇
  2024年   13篇
  2023年   83篇
  2022年   128篇
  2021年   235篇
  2020年   239篇
  2019年   177篇
  2018年   198篇
  2017年   175篇
  2016年   194篇
  2015年   206篇
  2014年   381篇
  2013年   421篇
  2012年   349篇
  2011年   304篇
  2010年   297篇
  2009年   269篇
  2008年   216篇
  2007年   224篇
  2006年   179篇
  2005年   149篇
  2004年   149篇
  2003年   119篇
  2002年   124篇
  2001年   97篇
  2000年   90篇
  1999年   81篇
  1998年   83篇
  1997年   62篇
  1996年   55篇
  1995年   39篇
  1994年   44篇
  1993年   53篇
  1992年   54篇
  1991年   39篇
  1990年   42篇
  1989年   48篇
  1988年   25篇
  1987年   31篇
  1986年   34篇
  1985年   40篇
  1984年   43篇
  1983年   31篇
  1982年   36篇
  1981年   31篇
  1980年   33篇
  1979年   19篇
  1978年   17篇
  1977年   11篇
  1976年   7篇
  1974年   6篇
排序方式: 共有5991条查询结果,搜索用时 15 毫秒
11.
A case is presented of a patient with incessant venfricular tacbycardia of left bundle branch block morphology. Endocardial mapping revealed the site of earliest activation during tachycardia to be the proximal right ventricular septum. Pacing at this site elicited the clinical tachycardia, whereas pacing at the proximal left ventricular septum induced a right bundle branch block morphology identical to that of a previously recorded spontaneous ventricuiar tachycardia. Electrophysiological evidence is given that both types of tachycardia originate from a single reentry circuit located in the proximal ventricular septum in which the reentrant wavefront may travel either orthodromically (during spontaneous tachycardia and right ventricular pacing) or antidromically (during left ventricular pacing).  相似文献   
12.
A model is described for obtaining long-term and stable discriminative conditioning-related slow-potential and single-unit responses from the frontal cortex of urethane-anesthetized rats. Responses were recorded and analyzed to reinforced (rewarding medial forebrain bundle stimulation) and non-reinforced tone cues. In the present study, cortical event-related slow potentials provided an adequate index of the level of discriminative conditioning. Single-unit response patterns are described for 57 neurons which demonstrated a discriminative response to either the reinforced or non-reinforced tone cue.  相似文献   
13.
电针结合电疗治疗老年习惯性便秘临床观察   总被引:1,自引:0,他引:1  
目的观察电针结合电疗治疗老年习惯性便秘的临床疗效。方法将60例老年习惯性便秘患者随机分为两组:治疗组30例运用电针结合电疗治疗,对照组30例服用麻仁软胶囊治疗。治疗第5天、第10天及随访1周时分别观察两组的总体疗效和主要症状变化。结果治疗组在这3个时段的总体疗效均优于对照组(P〈0.05),主要症状中便次和粪质改善治疗组优于对照组(P〈0.05)。结论电针结合电疗治疗老年习惯性便秘疗效确切。  相似文献   
14.
慢传输型便秘的病因研究进展   总被引:2,自引:0,他引:2  
慢传输型便秘是一种临床很常见的疾病,其症状十分顽固,但目前它的病因尚不清,所以给临床治疗带来很大困难。现就慢传输型便秘的多种发病原因,尤其是结肠蠕动方面的研究进展加以探讨,希望能给临床工作者带来一些帮助。  相似文献   
15.
OBJECTIVE: Colonic transit studies are used to diagnose slow transit constipation (STC) and to evaluate segmental colonic transit before segmental or subtotal colectomy. The aim of the study was to compare a single X-ray radio-opaque marker method with a scintigraphic technique to assess total and segmental colonic transit in patients with STC. METHOD: Thirty-one female patients (median age 46 years) with severe constipation and a prolonged or borderline prolonged colonic transit time on radio-opaque marker study were included in the study. They were subsequently investigated with (111)Indium-DTPA colonic transit scintigraphy, with a median time between the investigations of 4(range 1-27) months. Normal values of healthy female controls were used for comparison. RESULTS: There was no difference between the two methods in terms of prolonged or normal total colonic transit time. Twenty-nine of 31 female patients had a prolonged transit time only in one or two segments on the marker study. On scintigraphy, the transit time was prolonged for patients in the left (P < 0.05 to P < 0.001), but not in the right colon. With respect to prolonged or normal segmental transit time, there was a significant difference between the two methods only in the descending colon (P = 0.02). However, the results varied considerably for individual patients. CONCLUSION: Segmental colonic delay was a common finding. The two methods gave similar results for groups of patients, except in the descending colon. The variation of the results for individuals suggests that a repeated transit test may improve the assessment of total and segmental transit.  相似文献   
16.
肠易激综合征(IBS)是一组持续存在或反复发作的临床症候群,主要症状有腹痛、腹胀、排便习惯改变和大便性状异常、黏液便等,经检查排除可引起这些症状的器质性疾病。临床分为肝木乘脾型腹泻、脾胃虚弱型腹泻、脾肾阳虚型腹泻、肝郁脾虚型便秘四型,根据临床辨证分别施以不同治法,不同方药治疗,有显著疗效。同时,教育患者平时养成良好的饮食卫生习惯,不饮生水,不食生冷瓜果,忌食辛辣、油腻、肥厚之品,保持心情舒畅,怡情悦志,注意保暖,可加强疗效,防止复发。  相似文献   
17.
目的探讨使用大黄厚朴煎剂热敷脐部治疗胸腰椎术后患者腹胀、便秘的疗效。方法选择2005年1月至2006年12月中山大学第二医院骨外科胸腰椎术后出现腹胀便秘的患者80例。分成两组,治疗组用大黄厚朴煎剂热敷脐部;对照组使用开塞露塞肛。观察两组患者肛门排气,排便,腹胀消除及停药复结情况。结果治疗组的总有效率95%,对照组总有效率70%;停药复结情况:治疗组5%,对照组42.5%;腹胀减轻情况:治疗组95%,对照组52.5%。结论大黄厚朴煎剂热敷脐能有效减轻肠胀气,软化大便,对于消除胸腰椎术后患者腹胀便秘明显优于使用开塞露塞肛效果。  相似文献   
18.
Abstract  Although respiration in trained canines is well investigated, the process of preparing dogs has not been described in any great detail. Moreover, their daytime patterns of sleep and wakefulness during 1 or 2 h of electroencephalogram (EEG) and electrocardiogram (ECG) recordings are not clear. Therefore, we describe the process of selecting and training dogs, in which we recorded EEG and ECG in the laboratory. First, 14 of 1242 dogs dealt with over a 1 year period were chosen. They were trained for 2 h to lie quietly and to sleep in the laboratory; this training procedure was repeated 152 times. Three dogs were then selected and a permanent tracheostomy was performed in one. Finally, EEG and ECG were recorded with the bipolar fine needle electrodes; respiration was recorded simultaneously through a tube inserted to a tracheostomy in one dog. Wakefulness, slow wave sleep (SWS) and rapid eye movement (REM) sleep (REMS) were identified according to the EEG pattern and on the basis of the behavioral criteria. Recordings were performed 12 or 13 times in each dog. Complete sleep cycles, including wakefulness, SWS and REMS in this sequence, were observed 3.9–4.1 times. The mean duration of SWS was 2.2–4.4 min and that of REMS was 3.5–4.6 min. The REMS latency was 33.9–41.8 min. Fluctuation of heart rate with respiration, termed respiratory sinus arrhythmia, was noted in the ECG. Heart beat increased with inspiration and decreased with expiration. The present study demonstrates how to select and train sleeping dogs and shows their undisturbed daytime sleep and wakefulness patterns.  相似文献   
19.
排粪造影的临床应用   总被引:4,自引:3,他引:1  
介绍排粪造影方法,报告160例造影结果。对照组52例中2例(385%)异常;排粪障碍组108例,仅18例(1667%)未见异常,提出了肛直角和肛上距正常测量值。报道主要异常X线表现。探讨了排粪造影检查对于肛管直肠部及盆底疾病的诊断价值  相似文献   
20.
We wanted to clarify whether the postprandial intestinal feedback control activated by nutrients in the distal gut exerts different effects on motility, transit of digesta, and absorption of nutrients in the proximal gut. Additionally, interrelationships among motility, transit, and absorption were to be elucidated because these relationships have only been investigated in the fasted state. In five minipigs, a 150-cm segment of the proximal jejunum was isolated by two cannulas. Motility of the jejunal segment was recorded by multiple strain gauges and analyzed by computerized methods. Markers (Cr- and Cu-EDTA) were used for the measurement of the flow rate, transit time, and absorption of nutrients. After a meal, the test segment was perfused with 2 kcal/min of an elemental diet over a period of 90 min. A feedback inhibition was activated by infusion of nutrients into the midgut at rates of 1–4 kcal/min. Saline was infused as control. With increasing energy loads infused into the midgut, the motility index and the length of contraction waves decreased, whereas the incidence of stationary contractions increased, ie, the motility changed from a propulsive to a segmenting pattern. These modulations of motility were associated with a linear decrease in the flow rate and a linear increase in transit time. Flow and transit were linearly correlated with each other. Additionally, the reduction in flow rate and the delay in luminal transit were associated with a linear increase in the absorption of nutrients. However, the increase in absorption induced by the feedback mechanism was small (7.3–13.4%) compared to the marked inhibition of the motility parameters (54–64%), the flow rate (59%), and the delay of transit (5.8-fold). Feedback control primarily modulated motor patterns and luminal flow, whereas the small increase in absorption was only a side effect due to the longer contact time of the nutrients with the mucosa.The study was supported by the Deutsche Forschungsgemeinschaft, grant Eh 64/6-3.  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