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   15477篇
  免费   1490篇
  国内免费   267篇
耳鼻咽喉   140篇
儿科学   218篇
妇产科学   160篇
基础医学   1414篇
口腔科学   514篇
临床医学   1868篇
内科学   2148篇
皮肤病学   264篇
神经病学   738篇
特种医学   417篇
外国民族医学   3篇
外科学   3956篇
综合类   2295篇
一般理论   4篇
预防医学   624篇
眼科学   191篇
药学   1161篇
  17篇
中国医学   298篇
肿瘤学   804篇
  2024年   41篇
  2023年   355篇
  2022年   450篇
  2021年   738篇
  2020年   709篇
  2019年   680篇
  2018年   640篇
  2017年   580篇
  2016年   535篇
  2015年   502篇
  2014年   936篇
  2013年   946篇
  2012年   795篇
  2011年   888篇
  2010年   665篇
  2009年   682篇
  2008年   733篇
  2007年   716篇
  2006年   653篇
  2005年   556篇
  2004年   508篇
  2003年   384篇
  2002年   361篇
  2001年   327篇
  2000年   255篇
  1999年   226篇
  1998年   249篇
  1997年   252篇
  1996年   188篇
  1995年   181篇
  1994年   138篇
  1993年   167篇
  1992年   152篇
  1991年   126篇
  1990年   106篇
  1989年   107篇
  1988年   110篇
  1987年   71篇
  1986年   62篇
  1985年   101篇
  1984年   74篇
  1983年   62篇
  1982年   57篇
  1981年   40篇
  1980年   41篇
  1979年   19篇
  1978年   14篇
  1977年   19篇
  1976年   11篇
  1974年   9篇
排序方式: 共有10000条查询结果,搜索用时 46 毫秒
51.
52.
BACKGROUND: The aim of the present randomized study was to determine the effect of adding sufentanil to bupivacaine, compared with bupivacaine alone in caudal block, on the surgical stress response in children. METHODS: The children were premedicated with midazolam 0.5 mg/kg. All children received induction with nitrous oxide and sevoflurane. Anesthesia was maintained with the same volatile agents in the both groups. The children were randomly allocated to two groups. Group I received bupivacaine alone (n = 17) and group II received bupivacaine + sufentanil (n = 16). Caudal block was performed with 0.25% bupivacaine 2 mg/kg (group I) or 0.25% bupivacaine 2 mg/kg with sufentanil 0.5 microg/kg (group II) after induction of anesthesia. Blood samples were obtained after induction of anesthesia (T(0)) to measure baseline concentrations of cortisol, prolactin, glucose and insulin. Additional samples were obtained 30 min after the start of surgery (T(1)), and 60 min after the end of surgery (T(2)). RESULTS: All of the basal values (T(0)) were within the normal ranges of the authors' laboratory for children of this age group and there were no differences between the groups (P > 0.05). In both groups, glucose concentration increased at T(1), compared with T(0) and T(2) (P < 0.05). The glucose concentration was unchanged at T(2) compared with T(0) in both group (P > 0.05). In both groups, prolactin concentration increased at T(1), compared with T(0) and decreased at T(2), compared with T(1) (P < 0.05). Cortisol decreased at T(1) and T(2), compared with T(0) in both groups. (P < 0.05). Insulin concentration remained unchanged at T(0) and T(2), but increased slightly at T(1) in both groups (P > 0.05). There were no significant differences in plasma prolactin, cortisol, glucose and insulin levels between the two groups at T(1) and T(2) (P > 0.05). CONCLUSION: There is no advantage in adding 0.5 microg/kg sufentanil to bupivacaine over bupivacaine alone in the caudal block, with regard to the surgical stress response in children.  相似文献   
53.
AIMS: DDD-pacemakers are favoured in patients with sick-sinus-syndrome or AV-block. However, AAI-pacemakers for sick-sinus-syndrome or VDD-pacemakers for AV-block may provide similar benefit with lower costs. The aim is to show that a tailored approach (TA) with arrhythmia-specific pacemaker selection was equal to a standard approach (SA) regarding quality of life (QoL) at lower costs. METHODS AND RESULTS: The study was prospective and randomized with QoL as primary endpoint. Secondary endpoints were a combined endpoint of all-cause mortality, worsening heart failure or angina, atrial fibrillation (AF), stroke, these endpoints individually and costs. Of 198 patients (age 77 +/- 10 years, 43% female, ejection fraction 54 +/- 12%, follow-up 38 +/- 15 months), 94 were randomized to SA and 104 to TA. Thirty-two patients (34%) died in the SA group vs. 25 (24%) in the TA (P= ns). QoL showed no differences in all dimensions. The combined secondary endpoint was reached more frequently with SA (51%) compared to TA (37%, P = 0.045). There was no difference regarding all single secondary endpoints. Hardware costs were reduced by 15% (P < 0.0001). CONCLUSION: In long-term follow-up, a TA is equal to SA regarding the primary endpoint QoL and secondary endpoints as AF and mortality. Depending on the healthcare system, it may significantly reduce costs.  相似文献   
54.
Abstract:   We present a case of a 13-year-old boy who developed signs and symptoms of neuropathic pain/early Complex Regional Pain Syndrome (CRPS) Type I, formerly known as Reflex Sympathetic Dystrophy (RSD), after spraining his ankle while wrestling. Aggressive pain control, using medications and sympatholytic blocks, with physical therapy and rehabilitation, led to the resolution of his painful condition. This prevented the disease from possibly progressing to a full-blown case of CRPS I (RSD) that is very challenging to treat.  相似文献   
55.
放射性脑损伤是放射治疗的严重的并发症,其与脑肿瘤复发的鉴别诊断非常困难,目前主要依靠影像学诊断,核磁共振弥散加权像、磁共振波谱、正电子发射型计算机体层显像、单光子发射计算机体层显像等被认为对于鉴别诊断有一定的帮助,但其敏感性和特异性还有待于进一步研究。最终确诊依赖标本的组织学检查。  相似文献   
56.
A total of 114 patients with various sympathetic disorders underwent endoscopic sympathetic block over different thoracic ganglions by the clipping method. The advantages of this method include the recognition of the clipped level, changeability, and reversibility. However, 4.4% of patients were unilaterally clipped at the wrong level.  相似文献   
57.
颈髓血流障碍与脊髓型颈椎病发病机制的实验研究   总被引:1,自引:0,他引:1  
目的观察脊髓前动脉阻断对颈髓血供、功能的影响及其病理学变化,研究脊髓型颈椎病的发病机制。方法以家兔为实验模型,阻断C2段脊髓前动脉,在术后6h、24h、72h采用改良Tarlov法对动物行为学评级以及检测运动诱发电位的变化,应用激光多普勒血流测定仪测定颈髓血流灌注量,并观察兔颈髓组织细胞形态学、相关免疫组化的变化。结果术后各时相点神经功能减退,血流量下降明显,神经元骨架结构紊乱,细胞器破坏,出现急性缺血性改变。结论脊髓前动脉血流障碍可导致颈髓缺血性病变,引起脊髓的梗死,是脊髓型颈椎病发生不可忽视的重要因素,对其治疗应注意改善局部血液循环。  相似文献   
58.
本实验对“疆岳”驴(杂交驴)不同生长发育阶段的体高、体尺、体重进行了测定,并与南疆土种驴进行比较。研究结果表明,在不同的生长发育阶段实验组(杂交驴)的体高、体尺、体重各项指标均显著超过对照组(南疆土种驴),杂交效果显著。  相似文献   
59.
目的观察肝硬化病人乌司他丁预处理对罗库溴铵肌松作用的影响。方法选择30例患有肝硬化的成年手术病人,随机均分为两组:乌司他丁组(Ⅰ组),静注乌司他丁5000U/kg后1min,静脉给予罗库溴铵0.6mg/kg;生理盐水组(Ⅱ组),静脉给予生理盐水0.1ml/kg后1min,静脉给予罗库溴铵0.6mg/kg。另选15例无肝脏疾患的、ASAⅠ~Ⅱ级择期成年手术病人为对照组(Ⅲ组),处理同Ⅱ组。肌松监测仪检测四个成串刺激(TOF)的变化,记录三组注药后罗库溴铵的起效时间(注药到TOFr=0)、TOF无反应时间(T1=0持续时间)、T1最大抑制程度、临床时效(TOFr恢复至25%时间)、T1恢复至75%时间、恢复指数。结果与Ⅱ、Ⅲ组比较,Ⅰ组插管剂量罗库溴铵的起效时间明显延长(P<0.05)。Ⅱ、Ⅲ组罗库溴铵肌松的起效时间相似。与Ⅱ组比较,Ⅰ、Ⅲ组T1恢复25%时间和恢复指数明显缩短(P<0.05)。Ⅰ、Ⅲ组罗库溴铵肌松的恢复时间相似。结论肝硬化病人乌司他丁预处理延长罗库溴铵的起效时间,但缩短罗库溴铵肌松作用时间。  相似文献   
60.
甲磺酸罗比卡因与盐酸罗比卡因用于硬膜外阻滞的效应比较   总被引:10,自引:0,他引:10  
目的 评价甲磺酸罗比卡因用于硬膜外阻滞的效应和安全性。方法 45例择期行下腹或下肢手术病人,随机分别接受用甲磺酸罗比卡因(8.94 mg/ml,观察组)或盐酸罗比卡因(7.5mg/ml,对照组)施行的硬膜外阻滞。观察两组在感觉阻滞、运动阻滞、镇痛和肌肉松弛方面的效果,同时观察用药前后肝肾功能变化。结果 观察组和对照组感觉阻滞平面达到T6以上的病例分别为84.3%和76%(P>0.05),Bromage≥3级的病例分别90%和92%(P>0.05)。两组感觉阻滞平面固定时间、Bromage达到最大级别时间、最大级别维持时间和运动阻滞维持时间均无显著性差异(P>0.05)。两组镇痛及肌松满意率无显著性差异。观察组术中2例发生低血压,2例发生心动过缓,而对照组仅1例发生低血压。两组术后24 h天冬氨酸氨基转移酶(AST)、天冬氨酸转氨酶(ALT)、尿素氮(BUN)和肌酐(Cr)均在正常范围。结论 甲磺酸罗比卡因与盐酸罗比卡因行硬膜外阻滞的效应基本相同,且无明显毒性。  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