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   957篇
  免费   31篇
  国内免费   15篇
儿科学   4篇
基础医学   16篇
口腔科学   2篇
临床医学   174篇
内科学   191篇
神经病学   58篇
特种医学   411篇
外科学   30篇
综合类   56篇
预防医学   5篇
眼科学   2篇
药学   23篇
中国医学   2篇
肿瘤学   29篇
  2024年   3篇
  2023年   18篇
  2022年   38篇
  2021年   42篇
  2020年   41篇
  2019年   22篇
  2018年   27篇
  2017年   16篇
  2016年   7篇
  2015年   29篇
  2014年   75篇
  2013年   34篇
  2012年   48篇
  2011年   61篇
  2010年   51篇
  2009年   45篇
  2008年   41篇
  2007年   59篇
  2006年   63篇
  2005年   54篇
  2004年   39篇
  2003年   28篇
  2002年   35篇
  2001年   13篇
  2000年   12篇
  1999年   19篇
  1998年   19篇
  1997年   24篇
  1996年   17篇
  1995年   6篇
  1994年   12篇
  1993年   4篇
  1988年   1篇
排序方式: 共有1003条查询结果,搜索用时 187 毫秒
1.
目的 评价18F-脱氧葡萄糖(FDG)符合线路显像与异机CT图像融合诊断非小细胞肺癌(NSCLC)术后放化疗后复发转移的价值.方法 对可疑复发转移的40例NSCLC患者行18F-FDG符合线路显像,并于显像前后1周内行CT扫描.用三维(3D)图像融合软件进行图像融合.结果 在18F-FDG符合线路显像与CT扫描相同的范围内,40例患者共检出病灶58处,其中恶性52处,良性6处.融合图像诊断NSCLC复发转移的灵敏度、特异性、准确性、阳性预测值、阴性预测值、阳性似然比及阴性似然比分别为94.23%(49/52),5/6,93.10%(54/58),98.00%(49/50),5/8,5.65及0.07.图像融合灵敏度、准确性明显高于CT.单纯18F-FDG符合线路显像诊断效能与图像融合无差别,但与CT图像融合可明显提高对病灶的定位诊断(提高44.83%).结论 18F-FDG符合线路与CT图像融合诊断NSCLC术后放化疗后复发转移灵敏度高,定位准确,值得推广应用.  相似文献   
2.
目的 探讨靶心图上心肌灌注缺损区定量分析方法的可靠性、重复性及应用价值。方法 16例急性心肌梗死(AMI)行自体骨髓单个核细胞移植治疗的住院患者,于治疗前、治疗后45和90d行^99Tc^m-MIBI静息心肌灌注显像。在靶心图上勾画缺损区(在左心室靶心图中放射性计数低于40%的区域),并进行定量分析。结果 (1)不同操作者所得ROI结果之间的差异无统计学意义(t=0.52,P〉0.05)。(2)治疗后45d心肌灌注缺损区面积较治疗前缩小34.32%,差异有统计学意义(t=2.83,P〈0.05);治疗后90d心肌灌注缺损区面积较治疗后45d缩小14.77%,差异有统计学意义(t=2.51,P〈0.05)。示自体骨髓单个核细胞移植对缺血心肌的恢复有一定疗效,能够缩小梗死面积,且自体骨髓单个核细胞冠状动脉内移植治疗AMI的疗效在移植后早期(45d内)即有体现。(3)面积百分比是观察心肌灌注变化的重要定量指标。结论 该方法对心肌病变范围及严重程度能准确定量;对评价AMI骨髓于细胞移植术疗效有一定的价值。  相似文献   
3.
4.
国产腺苷介入心肌灌注断层显像对心肌缺血的诊断价值   总被引:9,自引:0,他引:9  
目的评价国产腺苷负荷心肌灌注断层显像对心肌缺血的诊断价值及腺苷试验的安全性。方法 102例临床疑冠心病患者行腺苷负荷/静息~(99)Tc~m-甲氧基异丁基异腈(MIBI)心肌灌注断层显像,其中70例显像1周内又行冠状动脉(简称冠脉)造影检查。腺苷按体重0.84 mg·kg~(-1)通过输液泵静脉双通路给药,对心肌灌注断层显像图作定性分析。结果 70例行冠脉造影者中正常31例,有冠脉狭窄病变者39例(单支病变19例,双支病变10例,3支病变10例);共检出病变血管69支,累及左前降支32支,左回旋支16支,右冠脉20支,左主干1支。腺苷负荷心肌灌注断层显像正常33例,心肌缺血37例,其对冠心病心肌缺血诊断的灵敏度为82.05%(32/39例),特异性为83.87%(26/31例),准确性为82.86%(58/70例),阳性预测值为86.49%(32/37例),阴性预测值为78.79%(26/33例)。对各病变血管检出的灵敏度为:左前降支75.00%(24/32支),左回旋支62.50%(10/16支),右冠脉80.00%(16/20支)。对单支、双支、3支血管病变诊断的灵敏度分别为68 42%、90.00%和100%。腺苷负荷心肌灌注断层显像对病变冠脉诊断总灵敏度为73.53%(50/68支),特异性96.48%(137/142支),准确性89.05%(187/210支),阳性预测值90.91%(50/55支),阴性预测值88.39%(137/155支)。腺苷试验不良反应轻,时间短,发生率为85.29%(87/102例)。结论国产腺苷负荷试验介入~(99)Tc~m-MIBI 心肌灌注断层显像安全可靠。  相似文献   
5.

Background  

This study compared the prognostic value of exercise single-photon emission computed tomographic (SPECT) thallium imaging with that of treadmill exercise score in medically treated patients with coronary artery disease (CAD)  相似文献   
6.
Reference data files support the evaluation of myocardial perfusion single-photon emission tomography (SPET). The aim of this study was to create a large reference data base for technetium-99m sestamibi SPET, age and gender matched to the general patient population. One hundred and twenty-eight healthy volunteers (76 males and 52 females) with a likelihood of coronary artery disease of less than 5% underwent rest and maximal exercise99mTc-sestamibi SPET with a 2-day protocol and 180° elliptical rotation. The normalized activity values of99mTc-sestamibi in the inferior wall differed significantly between men and women. Age variations were found for men in the anterior wall. Normalized activity values in all four walls were strikingly similar during rest and stress. Our results suggest that the use of reference files in99mTc-sestamibi SPET requires a gender- and, for males, possibly an age-matched reference population. Different reference files at rest and during stress might not be necessary.  相似文献   
7.
The mapping of 5-HT2 receptors in the brain using functional imaging techniques has been limited by a relative lack of selective radioligands. Iodine-123 labelled 4-amino-N-[1-[3-(4-fluorophenoxy)propyl]-4-methyl-4-piperidinyl]-5-iodo-2-methoxybenzamide (123I-5-I-R91150 or123I-R93274) is a new ligand for single-photon emission tomography (SPET), with high affinity and selectivity for 5-HT2A receptors. This study reports on preliminary123I-5-I-R91150 SPET, wholebody and blood distribution findings in five healthy human volunteers. Maximal brain uptake was approximately 2% of total body counts at 180 min post injection (p.i.). Dynamic SPET sequences were acquired with the brain-dedicated, single-slice multi-detector system SEM-810 over 200 min p.i. Early peak uptake (at 5 min p.i.) was seen in the cerebellum, a region free from 5HT2A receptors. In contrast, radioligand binding in the frontal cortex increased steadily over time, up to a peak at approximately 100–120 min p.i. Frontal cortex-cerebellum activity ratios reached values of 1.4, and remained stable from approximately 100 min p.i. onwards. Multi-slice SPET sequences showed a pattern of regional variation of binding compatible with the autoradiographic data on the distribution of 5-HT2A receptors in (cerebral cortex>striatum>cerebellum). These findings suggest that123I-5-I-R91150 may be used for the imaging of 5-HT2A receptors in the living human brain with SPET.  相似文献   
8.
Stress echocardiography has been considered an accurate method for the diagnosis of coronary artery disease in hypertensive patients and in patients with left ventricular hypertrophy. In contrast, the specificity of myocardial perfusion scintigraphy in these patients has been questioned. The aim of this study was to compare the accuracy of these two imaging modalities in conjunction with dobutamine stress test for the diagnosis of coronary artery disease in hypertensive patients with and without left ventricular hypertrophy. Dobutamine (up to 40 μg kg–1min–1) stress echocardiography in conjunction with sestamibi (MIBI) single-photon emission tomography (SPET) was performed in 84 patients with the diagnosis of systemic hypertension who had been referred for evaluation of myocardial ischaemia. Ischaemia was defined as new or worsened wall motion abnormalities at echocardiography and reversible perfusion defects at SPET. Significant coronary artery disease (≥50% luminal diameter stenosis) was detected in 66 patients (79%). The sensitivity, specificity and accuracy of the ischaemic pattern at echocardiography for the diagnosis of coronary artery disease were 73% (CI 63%–82%), 83% (CI 75%–91%) and 75% (CI 66%–84%), those for MIBI were 67% (CI 57%–77%), 83% (CI 75%–91%) and 70% (CI 60%–80%) respectively (P = NS vs echocardiography). Significant stenosis was detected in 123 (49%) of the 252 analysed coronary arteries. The sensitivity, specificity and accuracy of echocardiography for the regional diagnosis of coronary artery disease were 63% (CI 56%–69%), 90% (CI 86%–94%) and 77% (CI 72%–82%). Those for MIBI were 58% (CI 51%–64%), 91% (CI 87%–94%) and 75% (CI 69%–80) respectively (P = NS vs echocardiography). Left ventricular hypertrophy was detected in 59 patients (70%) by echocardiography and did not influence the overall or regional specificity of echocardiography or MIBI SPET. It is concluded that in hypertensive patients, dobutamine stress echocardiography and MIBI SPET have a comparable accuracy for the overall and regional diagnosis of coronary artery disease. Hypertensive patients with or without left ventricular hypertrophy should not be considered unsuitable candidates for stress myocardial perfusion scintigraphy. Received 10 July and in revised form 19 September 1997  相似文献   
9.
目的探讨肺肿瘤99Tcm-氮-二(N-乙基-N-乙氧基二硫代氨基甲酸盐)[N(NOEt)2]SPECT显像病变部位与对侧对应正常肺组织放射性比值(T/N)与术后病理组织中P-糖蛋白(P-gp)和肿瘤增殖细胞核抗原(PCNA)表达间的关系.方法对22例(20例为术前未经药物治疗的肺癌,2例为肺良性病变)患者进行手术,取肿瘤标本,经常规石蜡切片,用免疫组织化学技术检测病变组织P-gp和PCNA表达,并与术前99Tcm-N(NOEt)2 SPECT显像T/N比值对比.结果22例患者中,20例肺恶性肿瘤99Tcm-N(NOEt)2 SPECT显像均表现为异常放射性浓聚,T/N比值为1.29±0.04;2例肺良性病变99Tcm-N(NOEt)2显像T/N比值为1.08±0.13,其中1例为假阳性.22例患者除1例肺腺癌仅P-gp表达阴性外,其余患者P-gp、PCNA均呈阳性表达.22例患者99Tcm-N(NOEt)2SPECT延迟显像T/N比值与术后病理组织中P-gp和PCNA表达程度均无关(r值分别为0.123和-0.145,P均>0.05,双侧),且病理组织中P-gp与PCNA表达程度也无关(r=0.062,P>0.05,双侧).结论肿瘤细胞摄取99Tcm-N(NOEt)2与其P-gp和PCNA表达程度无关.  相似文献   
10.
目的 :探讨99mTc-MIBI心肌灌注断层显像在蒽环类药物心脏毒性监测中的价值。方法 :2 3例接受蒽环类药物治疗的患者 ,在治疗前进行心电图、心肌酶学检查、核素心室造影测左室射血分数 (LVEF)和99mTc MIBI心肌灌注断层显像并计算相对定量值。并于每一周期治疗后重复上述检查。结果 :蒽环类药物治疗一周期后 ,2 3例患者心肌相对定量值明显下降 (P <0 .0 1)。其中 11例吡喃阿霉素、6例表阿霉素和 6例米托蒽醌治疗的患者 ,心肌相对定量值明显下降 (P <0 .0 5 ) ,心电图和心肌酶学无明显变化 (P >0 .0 5 )。蒽环类药物治疗多周期后的 10例患者心肌相对定量值较治疗前下降 (P <0 .0 5 )。 9例患者的心肌相对定量值 (最大累积剂量为 2 0 0mg/m2 )与一周期后无明显差别 (P >0 .0 5 )。10例患者治疗前及多周期治疗后LVEF均 >6 0 %,且化疗前后无明显差别 (P >0 .0 5 )。结论 :99mTC MIBI心肌灌注断层显像能监测蒽环类药物所致的心肌损害 ,且较左室射血分数敏感 ,比心电图和心肌酶学检查优越 ,有利于指导蒽环类药物的临床应用。  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