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   643篇
  免费   23篇
  国内免费   2篇
耳鼻咽喉   10篇
儿科学   32篇
妇产科学   12篇
基础医学   55篇
口腔科学   12篇
临床医学   63篇
内科学   140篇
皮肤病学   6篇
神经病学   18篇
特种医学   193篇
外科学   32篇
综合类   13篇
预防医学   25篇
眼科学   6篇
药学   26篇
  1篇
中国医学   6篇
肿瘤学   18篇
  2023年   3篇
  2021年   3篇
  2018年   2篇
  2017年   3篇
  2016年   4篇
  2015年   9篇
  2014年   2篇
  2013年   14篇
  2012年   7篇
  2011年   20篇
  2010年   24篇
  2009年   18篇
  2008年   9篇
  2007年   18篇
  2006年   17篇
  2005年   13篇
  2004年   5篇
  2003年   6篇
  2002年   8篇
  2001年   7篇
  2000年   9篇
  1999年   7篇
  1998年   30篇
  1997年   24篇
  1996年   30篇
  1995年   39篇
  1994年   31篇
  1993年   26篇
  1992年   11篇
  1991年   3篇
  1990年   6篇
  1989年   25篇
  1988年   22篇
  1987年   25篇
  1986年   30篇
  1985年   16篇
  1984年   15篇
  1983年   12篇
  1982年   11篇
  1981年   15篇
  1980年   15篇
  1979年   7篇
  1978年   13篇
  1977年   9篇
  1976年   10篇
  1975年   11篇
  1974年   2篇
  1969年   2篇
  1958年   4篇
  1957年   6篇
排序方式: 共有668条查询结果,搜索用时 0 毫秒
71.
为摸清我省儿童1型糖尿病的发病情况,按WHO儿童糖尿病多国研究计划方案,我们在自贡市(四区,两县)对1989~1996年儿童1型糖尿病发病率进行了调查研究。1 材料与方法1.1 病例来源 第一来源:自贡市30个县区级有1型糖尿病诊断能力的医院。第二来...  相似文献   
72.
The Clinical Ethics Credentialing Project (CECP) was intiated in 2007 in response to the lack of uniform standards for both the training of clinical ethics consultants, and for evaluating their work as consultants. CECP participants, all practicing clinical ethics consultants, met monthly to apply a standard evaluation instrument, the “QI tool”, to their consultation notes. This paper describes, from a qualitative perspective, how participants grappled with applying standards to their work. Although the process was marked by resistance and disagreement, it was also noteworthy for the sustained engagement by participants over the year of the project, and a high level of acceptance by its conclusion.  相似文献   
73.

Background:

Monoamine reuptake inhibitors exhibit unique clinical profiles that reflect distinct engagement of the central nervous system (CNS) transporters.

Methods:

We used a translational strategy, including rodent pharmacokinetic/pharmacodynamic modeling and positron emission tomography (PET) imaging in humans, to establish the transporter profile of TD-9855, a novel norepinephrine and serotonin reuptake inhibitor.

Results:

TD-9855 was a potent inhibitor of norepinephrine (NE) and serotonin 5-HT uptake in vitro with an inhibitory selectivity of 4- to 10-fold for NE at human and rat transporters. TD-9855 engaged norepinephrine transporters (NET) and serotonin transporters (SERT) in rat spinal cord, with a plasma EC50 of 11.7ng/mL and 50.8ng/mL, respectively, consistent with modest selectivity for NET in vivo.Accounting for species differences in protein binding, the projected human NET and SERT plasma EC50 values were 5.5ng/mL and 23.9ng/mL, respectively. A single-dose, open-label PET study (4–20mg TD-9855, oral) was conducted in eight healthy males using the radiotracers [11C]-3-amino-4- [2-[(di(methyl)amino)methyl]phenyl]sulfanylbenzonitrile for SERT and [11C]-(S,S)-methylreboxetine for NET. The long pharmacokinetic half-life (30–40h) of TD-9855 allowed for sequential assessment of SERT and NET occupancy in the same subject. The plasma EC50 for NET was estimated to be 1.21ng/mL, and at doses of greater than 4mg the projected steady-state NET occupancy is high (>75%). After a single oral dose of 20mg, SERT occupancy was 25 (±8)% at a plasma level of 6.35ng/mL.

Conclusions:

These data establish the CNS penetration and transporter profile of TD-9855 and inform the selection of potential doses for future clinical evaluation.  相似文献   
74.
目的:研究唐古特大黄提取物不同成分的泻下作用。方法:采用炭末推进方法、酚红排空方法进行肠推进实验,观察大黄提取物各成分(15 g·kg-1)对小鼠小肠推进和肠水分吸收、大鼠大肠运动的影响。结果:唐古特大黄提取物不同成分与对照组相比,对小鼠小肠推进和肠水分吸收、大肠推进作用均有显著性差异(P<0.01);与大黄水煎液、醇提液相比,泻下活性存在一些差异。结论:唐古特大黄提取物不同成分均有显著的泻下作用,但与大黄水煎液和醇提液相比有一些差异。  相似文献   
75.
目的:研究藏药七十味珍珠丸中汞的5种存在形态和分布.方法:将七十味珍珠丸中汞的形态分为水溶态汞、溶于盐酸的无机汞和有机汞、络合汞、单质汞和残渣态汞,通过电感耦合等离子体原子发射光谱(ICP-AES)法分析5种形态汞的含量和分布.结果:藏药七十味珍珠丸中总汞的93.8%是以惰性汞形式存在的硫化汞,6.18%是与锌、铝、钙...  相似文献   
76.
笔者基于同气相求理论,遵循经络辨证,以求同气、通经络为治则,针刺患侧或双侧手足少阳经远端激痛点及井穴,同时按揉近端激痛点,治疗顽固性偏头痛15例,现报道如下。1临床资料15例患者均为2018年1月至2018年6月包头医学院第二附属医院针灸科门诊就诊的顽固性偏头痛患者,其中男6例,女9例;单侧头痛9例,双侧6例;年龄15~65岁,平均46岁;病程0.5~15年,平均2年。均表现为单侧或双侧颞部反复发作的搏动性疼痛,伴失眠、健忘,痛甚者恶心,行头颅CT或MRI检查未见异常。  相似文献   
77.
彩色多普勒超声在移植肾急性排异反应中的应用   总被引:1,自引:1,他引:0  
目的 应用彩色多普勒超声寻找移植肾急性排异反应较为特异的诊断指标.方法 经移植肾穿刺活检证实的急性排异反应患者42例,经长期随访(1年以上)和临床检查证实的功能稳定期患者115例.对两组移植肾长径、宽径、厚径、实质厚度以及主肾动脉和弓状动脉的阻力指数(RI)进行统计学比较;选取肾体积增大,锥体肿大回声减低、RI<0.7、RI≥0.7及RI≥0.8作为诊断标准,按诊断试验评价原则分别计算灵敏度、特异度、误诊率、漏诊率和符合率;并绘制ROC曲线,确定诊断界值.结果 两组的移植肾长径、宽径、厚径及实质厚度差异有统计学意义(P<0.05);急性排异反应组肾内血流灌注减少,肾动脉舒张期血流速度明显下降,RI明显增高,与移植肾功能稳定期比较差异有统计学意义(P<0.05);各诊断标准对应的灵敏度分别为55.30%,55.20%,42.10%,57.90%和31.60%;特异度分别为71.30%、87.10%、25.70%、74.20%、98.20%.结论 肾体积增大、肾锥体肿大、回声减低、RI升高对诊断移植肾急性排异反应有特异性.  相似文献   
78.
    
Background: Item response theory (IRT; Lord & Novick, 1968) is a psychometric framework that can be used to model the likelihood that an individual will respond correctly to an item. Using archival data (Mirman et al., 2010), Fergadiotis, Kellough, and Hula (2015) estimated difficulty parameters for the Philadelphia Naming Test (PNT; Roach, Schwartz, Martin, Grewal, & Brecher, 1996) using the 1-parameter logistic IRT model. Although the use of IRT in test development is advantageous, its reliance on sample sizes exceeding 200 participants make it difficult to implement in aphasiology. Therefore, alternate means of estimating the item difficulty of confrontation naming test items warrant investigation. In a preliminary study aimed at automatic item calibration, Swiderski, Fergadiotis, and Hula (2016) regressed the difficulty parameters from the PNT on word length, age of acquisition (Kuperman, Stadthagen-Gonzalez, & Brysbaert, 2012), lexical frequency as quantified by the Log10CD index (Brysbaert & New, 2009), and naming latency (Székely et al., 2003). Although the model's predictive utility was high, a substantial proportion (20%) of the response time data were missing. Further, only 39% of the picture stimuli from Székely and colleagues (2003) were identical to those on the PNT. Given that the IRT sample size requirements limit traditional calibration approaches in aphasiology and that the initial attempts in predicting IRT difficulty parameters in our pilot study were based on incomplete response time data this study has two specific aims.

Aims: To estimate naming latencies for the 175 items on the PNT, and assess the utility of psycholinguistic variables and naming latencies for predicting item difficulty.

Methods and Procedures: Using a speeded picture naming task we estimated mean naming latencies for the 175 items of the PNT in 44 cognitively healthy adults. We then re-estimated the model reported by Swiderski et al (2016) with the new naming latency data.

Outcomes and Results: The predictor variables described above accounted for a substantial proportion of the variance in the item difficulty parameters (Adj. R2 = .692).

Conclusions: In this study we demonstrated that word length, age of acquisition, lexical frequency, and naming latency from neurotypical young adults usefully predict picture naming item difficulty in people with aphasia. These variables are readily available or easily obtained and the regression model reported may be useful for estimating confrontation naming item difficulty without the need for collection of response data from large samples of people with aphasia.  相似文献   

79.
Multisection-multiecho MR imaging: effect on image quality   总被引:1,自引:0,他引:1  
Fitzsimmons  JR; Googe  RE 《Radiology》1985,157(3):813-814
An analysis of the effects of multisection-multiecho imaging on signal intensity is presented using a gaussian excitation pulse. The number of sections acquired, size of the intersection gap, and the number of echoes were all varied independently to evaluate their effect on image intensity. The results indicate that one should take a conservative approach in multisection-multiecho imaging, leaving at least a 2-mm-intersection gap and approximately a 20-msec delay between section excitations to avoid image signal loss owing to partial saturation effects.  相似文献   
80.
Efficacy study of the small-bowel examination   总被引:8,自引:0,他引:8  
  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