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   21202篇
  免费   2097篇
  国内免费   1742篇
耳鼻咽喉   187篇
儿科学   292篇
妇产科学   301篇
基础医学   2167篇
口腔科学   542篇
临床医学   2647篇
内科学   2750篇
皮肤病学   216篇
神经病学   837篇
特种医学   982篇
外国民族医学   10篇
外科学   2142篇
综合类   4195篇
现状与发展   2篇
一般理论   1篇
预防医学   1638篇
眼科学   610篇
药学   2372篇
  31篇
中国医学   1502篇
肿瘤学   1617篇
  2024年   86篇
  2023年   353篇
  2022年   869篇
  2021年   1042篇
  2020年   871篇
  2019年   701篇
  2018年   737篇
  2017年   669篇
  2016年   610篇
  2015年   969篇
  2014年   1122篇
  2013年   1132篇
  2012年   1638篇
  2011年   1673篇
  2010年   1213篇
  2009年   1062篇
  2008年   1254篇
  2007年   1182篇
  2006年   1119篇
  2005年   1068篇
  2004年   803篇
  2003年   854篇
  2002年   753篇
  2001年   568篇
  2000年   443篇
  1999年   370篇
  1998年   287篇
  1997年   259篇
  1996年   204篇
  1995年   181篇
  1994年   159篇
  1993年   102篇
  1992年   94篇
  1991年   81篇
  1990年   63篇
  1989年   59篇
  1988年   67篇
  1987年   61篇
  1986年   47篇
  1985年   66篇
  1984年   20篇
  1983年   17篇
  1982年   26篇
  1981年   14篇
  1980年   25篇
  1979年   5篇
  1978年   4篇
  1977年   14篇
  1976年   15篇
  1975年   9篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
肿瘤转移抑制基因KAI1在喉鳞状细胞癌中表达的研究   总被引:1,自引:0,他引:1  
目的 探讨肿瘤转移抑制基因KAI1在喉鳞状细胞癌 (简称鳞癌 )中的表达及其与之发生、发展的关系。方法 采用原位杂交方法检测 84例原发性喉鳞癌 (primarylaryngealsquamouscellcarcinoma ,PLSCC)、2 7例喉癌前病变不典型增生 (laryngealprecancerouslesion ,LPL)、10例声带息肉(vocalcordpolyp ,VCP)和 10例正常喉黏膜 (normallaryngealtissues ,NLT)石蜡标本组织细胞中KAI1mRNA的表达。结果 NLT、VCP、LPL和PLSCC 4种组织中KAI1阳性表达的积分吸光度值 ( x±s)分别为 (136 2 0 6 8± 36 6 75 5 )、(1336 74 5± 4 2 85 8 5 )、(90 36 8 8± 2 5 70 1 9)和 (6 7880 6± 2 8189 5 ) ,其中NLT组和VCP组之间差异无显著性 (t=0 14 2 ,P >0 0 5 ) ,NLT组和LPL组之间差异有显著性 (t =4 2 81,P <0 0 1) ;PLSCC组中KAI1表达普遍下调 ,且病理分化G1 2组阳性表达水平高于G3组 ;T1 2病变组高于T3 4组 ;颈淋巴结NO组高于N1及N1以上组 ;临床Ⅰ Ⅱ期组高于临床Ⅲ Ⅳ期组 (P值均 <0 0 1)。KAI1表达与患者性别无关 (P >0 0 5 )。结论 KAI1低表达在喉鳞癌的发生、发展中可能起着重要作用 ,可望作为喉鳞癌早期诊断、评估肿瘤细胞侵袭转移潜能及患者病程发展阶段的指标之一。  相似文献   
12.
不同种属脱细胞真皮与自体皮复合移植的比较性研究   总被引:5,自引:2,他引:3  
目的 观察不同种属脱细胞真皮基质 (acellulardermalmatrix,ADM)与自体皮复合移植的效果 ,为异种ADM的临床应用提供理论依据。 方法 本地产白色小猪 6头 ,分为异种 (人 )ADM +自体刃厚皮组 (A组 )、同种异体 (猪 )ADM +自体刃厚皮组 (B组 )、单纯自体刃厚皮组 (C组 )及单纯自体中厚皮组 (D组 )。观察术后 2、4、8、12、2 4周内移植物存活率 ,以及移植皮片收缩程度、移植区组织学变化等情况。 结果 A、B组移植后皮片外观光滑、有弹性 ;两组均获得了满意的皮片成活率 ,并可迅速诱导成纤维细胞、血管内皮细胞等宿主修复细胞的长入 ;两组移植皮片收缩面积有大于C、D组的趋势 (P <0.0 5);术后 2 4周移植区组织与单纯中厚皮移植组织结构一致。 结论 在观察期内(复合移植后 2 4周 ) ,与自体皮复合移植时 ,同、异种ADM具有相近的生物学作用 ,异种来源的ADM可能具有更广阔的应用前景  相似文献   
13.
扩散法被动式甲醛个体监测器(Ⅱ型)的研制   总被引:1,自引:0,他引:1  
介绍了一种基于气体分子扩散原理的被动式甲醛个体采样器,它是在Ⅰ型采样器的基础上完成的。采用甘油(20%)/偏重亚硫酸钠(0.25%)浸渍的定量滤纸(φ42mm)作为吸收层,空气中甲醛扩散到吸收层上,形成稳定的化合物。采样一定时间后,取出吸收层,洗脱后,用AHMT化学比色法测定所采集到的甲醛。这种采样器的平均采样速率为83ml/min,标准偏差为7.2ml/min,与有动力吸收管采样的方法相比较,总不确定度小于±25%。  相似文献   
14.
在微量注射大量肝脏mRNA之后,通过电压箝方法进行功能鉴定,两栖类卵母细胞成功地表达了AVPV1a受体。但在灌流AV4-8溶液时,却不能诱导卵母细胞产生内向振荡电流反应。提示AVP4-8不能通过AVPV1a受体而介导生理学效应。  相似文献   
15.
目的:探讨血管内皮生长因子在肺癌中的表达情况与肺癌病理生物学行为之间的关系。方法:采用免疫组化SP法检测47例肺癌组织和10正常肺组织中VEGF的表达水平。结果:肺癌组织中VEGF的表达明显高于正常肺组织(P<0.005),P53、VEGF表达与肺癌的分化程度、淋巴结转移及P—TNM分期密切相关(P<0.05),与患者的性别、年龄、肿瘤大小及组织类型无关(P>0.05)。结论:检测肺癌组织中VEGF的表达水平有助于了解肿瘤的生物学行为,并可作为判断其预后的有价值指标。  相似文献   
16.
With the development of interventional therapy, it is necessary for evaluating cerebral vessels to instruct treatment and determine prognosis of patients with ischemic stroke; however, correlation of distribution of infarction focus and clinical symptoms with degrees of cerebrovasoular stricture is still unclear.OBJECTIVE: To evaluate the characteristics of cerebral arterial stricture of patients with ischemic stroke with transcranial Doppler (TCD) and color duplex flow imaging (CDFI) and compare the correlation between distribution of cerebral infarction focus and clinical types with magnetic resonance imaging (MRI).DESIGN: Contrast observation.SETTING: Department of Neurology, the First Hospital of Jilin University.PARTICIPANTS: A total of 159 patients with ischemic stroke were selected from the Department of Neurology, the First Hospital of Jilin University from January to December 2005, including 106 males and 53 females aged from 27 to 88 years. Bases on diagnostic criteria of cerebrovascular disease established by Rao et al, clinical manifestations of all patients were evaluated with CT or nuclear magnetic resonance. All patients provided the confirmed consent.METHODS: The accepted patients received TCD and CDFI examination at 1 week after onset of ischemic stroke. Among them, 112 patients received cerebrovascular imaging examination simultaneously. MRI was used to check cerebral infarction focus and cerebrovascular stricture > 50% was regarded as the accepted vessels. In addition, DWI-T2 TCD (Germany) was used to check middle cerebral artery, and degrees of middle cerebral artery were classified into mild, moderate and severe stricture based on blood velocity (140 cm/s,180 cm/s). Stroke was classified based on characteristics of infarction focus and clinical symptoms showed with MRI and correlation with degrees of cerebrovascular stricture was analyzed simultaneously.MAIN OUTCOME MEASURES: Correlation between the characteristics of ischemic stroke and clinical symptoms checked with TCD and CDFI.RESULTS: A total of 159 patients with ischemic stroke were involved in the final analysis; in addition, 112 oases received cerebrovascular imaging examination simultaneously. ① MRI results of 159 patients with cerebral artery occlusive disease (CAOD): There were 131 patients (82.3%) with cerebral infarction, 40 (25.2%)with transient ischemic attack and 4 (2.5%) with subclavian steal syndrome (SSS). ② Infarction types with MRI examination: There were 33 patients (20.8%) with solitary cerebral infarction and 98 (61.6%) with multiple-cerebral infarction. ③ Results of TCD, CDFI, MRI angiography, CT angiography and digital subtraction angiography (DSA): Among 112 patients, 181 lesion sites (61 .8%) were located in cranium and 112 lesion sites were located out of cranium; especially, lesion site was mostly observed in stem of middle cerebral artery (31.2%) and watershed of basilar artery (7.2%) in cranium and the beginning site of internal carotid artery (21 .4%) out of cranium. ④ Correlation of vascular stricture checking with TCD, MRI and clinical diagnosis: On one hand, MRI and clinical diagnosis demonstrated that 68 patients had a watershed infarction; meanwhile,TCD examination indicated that there were 3 patients with mild vascular stricture, 24 with moderate vascular stricture and 36 with severe vascular stricture. On the other hand, among 68 patients with non-watershed infarction, there were 27 patient with mild vascular stricture, 26 with moderate vascular stricture and 15 with severe vascular stricture. There were significant differences (x2 =26.854, P =0.001 ). Clinical diagnosis indicated that 40 patients had transient ischemic attack and TCD examination demonstrated that there were 8 patient with mild vascular stricture, 12 with moderate vascular stricture and 20 with severe vascular stricture. There were significant differences as compared with 68 patients with watershed infarction (x2 =21.258, P =0.001). ⑤Correlation of vascular stricture checking with CDFI, MRI and clinical diagnosis: On one hand, among patients who were determined as watershed infarction with MRI and clinical diagnosis, CDFI examination indicated that there were 32 patients with mild vascular stricture at neck, 25 with moderate vascular stricture and 6 with severe vascular stricture. On the other hand, among patients with non-watershed infarction, there were 48 patient with mild vascular stricture, 18 with moderate vascular stricture and 2 with severe vascular stricture.There were significant differences (x2 =6.018, P =0.019). Among patients with transient ischemic attack checking with clinical diagnosis, there were 23 patient with mild vascular stricture, 9 with moderate vascular stricture and 8 with severe vascular stricture. There were no significant differences as compared with patients with non-watershed infarction (x2 =0.597, P=0.440).CONCLUSION: ① TCD and CDFI are effective marks to determine cerebral arterial stricture and hemodynamical changes. ② Infarction and transient ischemic attack at watershed are generally clinical phenotypes of CAOD patients and infarction at watershed is correlated with degrees of cerebrovascular stricture.③ TCD, MRI and clinical analysis of stroke types are significant for instructing treatment and evaluate prognosis.  相似文献   
17.
Abstract – Dental injuries are common following facial trauma. This article presents a rare injury: the dislocation of a third molar into the maxillary sinus after complex mandibular and maxillary tuberosity fractures. The possible mechanism and clinical treatment are discussed.  相似文献   
18.
目的:总结2岁~12岁小儿增殖腺肥大平片表现介绍测量方法;材料与方法:25小儿增殖腺肥大患儿常规摄鼻咽部侧位片均匀吸气拍照,采用鼻咽增殖腺厚度最突出部与鼻咽腔宽度比值;结果:鼻咽顶部咽后壁软组织增厚,鼻咽气道狭窄,腺/咽比值>0.8,3例;>0.7,16例;>0.6,6例;结论:均匀吸气时摄片,观察增殖腺大小形态方法简单、准确可靠。  相似文献   
19.
A case of β-thalassemia major with a huge mass of hernatopoictic tissuc firmly attached tothe dura mater was reported This is the first case reported in China.  相似文献   
20.
超声对宫角妊娠的诊断及治疗意义   总被引:5,自引:0,他引:5  
杨新  柳建华等 《医学文选》2002,21(4):444-446
目的 探讨对误诊率高,危害大的罕见特殊部位宫角妊娠的诊断和治疗。方法 对我院1991-2001年收治的宫角妊娠临床资料进行回顾性分析。结果 宫角妊娠17例中误诊宫内妊娠行人流失败4例。13例行腹部手术,3例行B超监视下人流术,1例行子宫动脉栓塞术。结论 宫角妊娠临床诊断困难,误诊率高,破裂后造成迅猛的腹腔内出血,应提高对少见部位宫角妊娠的认识,减少孕妇死亡。  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