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   7245篇
  免费   677篇
  国内免费   617篇
耳鼻咽喉   47篇
儿科学   80篇
妇产科学   58篇
基础医学   842篇
口腔科学   119篇
临床医学   983篇
内科学   1063篇
皮肤病学   78篇
神经病学   410篇
特种医学   366篇
外国民族医学   8篇
外科学   706篇
综合类   1206篇
现状与发展   5篇
预防医学   499篇
眼科学   277篇
药学   850篇
  1篇
中国医学   330篇
肿瘤学   611篇
  2024年   22篇
  2023年   105篇
  2022年   258篇
  2021年   362篇
  2020年   253篇
  2019年   239篇
  2018年   229篇
  2017年   209篇
  2016年   223篇
  2015年   310篇
  2014年   399篇
  2013年   344篇
  2012年   514篇
  2011年   551篇
  2010年   332篇
  2009年   298篇
  2008年   343篇
  2007年   439篇
  2006年   299篇
  2005年   345篇
  2004年   242篇
  2003年   254篇
  2002年   226篇
  2001年   224篇
  2000年   216篇
  1999年   215篇
  1998年   130篇
  1997年   138篇
  1996年   93篇
  1995年   78篇
  1994年   76篇
  1993年   64篇
  1992年   50篇
  1991年   42篇
  1990年   35篇
  1989年   63篇
  1988年   51篇
  1987年   40篇
  1986年   38篇
  1985年   33篇
  1984年   18篇
  1983年   9篇
  1982年   13篇
  1981年   9篇
  1980年   12篇
  1978年   8篇
  1977年   8篇
  1972年   11篇
  1971年   7篇
  1970年   9篇
排序方式: 共有8539条查询结果,搜索用时 46 毫秒
31.
用9周-39周引产胎儿标本72例,取右耳廓石蜡切片,HE和Weitert弹性纤维染色,光镜观察其弹性软骨、弹性纤维、耳廓肌和结缔组织的发生。  相似文献   
32.
显微定量法测定中成药中猪牙皂的含量   总被引:2,自引:0,他引:2  
目的 :制定猪牙皂在脐风散与惊风散中的显微定量标准。方法 :用显微定量法 ,以猪牙皂特有的石细胞为显微特征物 ,对脐风散与惊风散中的猪牙皂进行测定。结果 :猪牙皂含量与每毫克特征数呈显著的线性正相关 ,回归方程为 y =61 .42 x -1 .1 0× 1 0 - 3(γ=1 .0 0 ,α=0 .0 5 )。结论 :显微定量法测定脐风散与惊风散中猪牙皂的含量是可行的 ,结果可靠  相似文献   
33.
OBJECTIVE: To investigate the association of Malassezia furfur with chronic urticaria in the crew members of ships. METHODS: A comparative mycological study of 126 crew members of ships with chronic urticaria and 45 normal control subjects was carried out. The 82 urticaria patients identified as positive for Malassezia furfur were divided into groups A and B to receive treatment with antihistaminics (group A) and antihistaminics combined with 2% ketoconazole shampoo(group A). RESULTS: The carrier rates of Malassezia furfur were significantly higher in urticaria patients than in the normal control subjects (P<0.01), but in view of the case ratios of the final cure or improvement, no significant difference was observed between the two groups by the end of the treatment courses (P>0.05). But 6 to 8 weeks from the end of the treatment course, better therapeutic effect was noted in group B (P<0.01), with higher rate of negative Malassezia furfur findings (P<0.01). CONCLUSION: Malassezia furfur may play an important role in the prevalence of chronic urticaria among the crew members, and anti-fungal treatment may produce better long-term therapeutic effect.  相似文献   
34.
BACKGROUND: Growing interest is nowadays focused on the quality of life of elderly people who survive with chronic diseases. Coronary heart disease (CHD) is one of the most common diseases among the elderly and may have an unfavourable impact on the patient's emotional well-being. OBJECTIVES: We aimed to describe the prevalence of depression and the occurrence of depressive symptoms among elderly CHD patients, with a special emphasis on the relations between depression and the severity of CHD, and to find out the possible association between CHD and depression. METHODS: The study was carried out at the health centre of the municipality of Lieto, in south-west Finland. The study population consisted of 488 community-dwelling men and 708 women, over 64 years old, from among whom the participants with CHD (89 men and 73 women) were selected, and for whom 178 male and 146 female sex- and age- matched controls (free of CHD) were drawn from the population. CHD patients were selected on the basis of the presence of angina pectoris or a past myocardial infarction. Depressive symptoms were measured with the Zung Self-rating Depression Scale. Depression was described in relation to the severity of dyspnoea and chest pain among patients. The associations between depression and age, health, health behaviour, drugs, functional ability and social, psychosocial and environmental factors were analysed by logistic regression analyses. RESULTS: The prevalence of depression was 29% among male patients and 20% among female patients. Depression was significantly more common among male CHD patients than among male controls (P = 0.011). Among women, depression was not associated with CHD. Earlier, depression had gone undiagnosed among many CHD patients and controls, especially male patients. Among male CHD patients, depression was associated with more severe dyspnoea, but no similar association was found among female CHD patients. Among men the occurrence of CHD, physical disability, widowhood or divorce, and among women previous clinical depression, physical disability and the use of angiotensin-converting enzyme (ACE) inhibitors, were associated with depression. CONCLUSION: Depression is common among patients with CHD. It seems that CHD is not an independent factor in the aetiology of depression among the elderly. The association of CHD with depression among men is explained by the acute or chronic psychic stress caused by CHD. It may be that the more complicated the patient's CHD, the more probable is the presence of depression.   相似文献   
35.
用鸡胚卵黄囊分离斑点热群立克次体的研究   总被引:7,自引:0,他引:7  
本文在用传统的实验动物感染法分离立克次体同时,并尝试用鸡胚卵黄囊培养法直接分离立克次体。结果:用前者未分离出立克次体,而用后者分别从来自北京昌平县的中华革蜱和来自黑龙江省虎林县的嗜群血蜱中各分离到1株立克次体。经鉴定,这两株立克次体属于斑点热群立克次体。结论:鸡胚卵黄囊培养法可以直接从现场节肢动物标本中分离病原体。  相似文献   
36.
自体皮源奇缺条件下瘢痕挛缩畸形的晚期临床修复   总被引:11,自引:6,他引:5  
目的寻找对烧伤后畸形伴自体皮源奇缺患进行晚期修复的新方法。方法5例特重度、特大面积烧伤患治愈后伴较严重畸形,且自体皮源奇缺。采用柔软成熟的瘢痕皮肤作为修复的皮源,用扩张器扩张瘢痕皮肤后,切取中厚瘢痕皮片进行修复;不宜行瘢痕皮肤扩张术时,切取刃厚瘢痕皮片与异体脱细胞真皮基质组成复合皮进行修复。观察两种方法的疗效。结果所移植的扩张瘢痕皮片和复合皮均成活,功能和外形恢复良好,远期疗效近似正常自体中厚皮移植。结论采用不同厚度的瘢痕皮片修复烧伤畸形是可行的,可扩大自体皮源。此法对于皮源奇缺的瘢痕患尤其适用。  相似文献   
37.
The renal insulin-like growth factor-I (IGF-I) system has been implicated in the pathogenesis of renal hypertrophy, altered hemodynamics, and extracellular matrix expansion associated with early diabetes. The relative abundance of IGF binding proteins (IGFBPs) in the renal microenvironment may modulate IGF-I actions. However, the precise IGFBPs expressed in the glomerular and tubulointerstitial compartments during diabetic renal growth have not been characterized. In the present study, in situ hybridization studies were performed to examine the expression of IGFBP-1 to -6 messenger RNAs (mRNAs) 3, 7, and 14 days after streptozotocin (STZ) injection in rats. In control, nondiabetic kidneys, all six IGFBP mRNAs were differentially expressed with a predominance of IGFBP-5. The onset of renal hypertrophy in STZ-induced diabetes was associated with a rapid and site-specific induction of IGFBP-1, -3, and -5 mRNAs. In contrast, basal expression of IGFBP-2, -4, and -6 mRNAs was not altered in diabetic rats. IGFBP-5 mRNA expression increased in diabetic glomeruli, cortical, and inner medullary peritubular interstitial cells at days 3, 7, and 14. Although normal glomeruli failed to express IGFBP-3, it was induced concomitantly with IGFBP-5 in diabetic glomeruli and cortical peritubular interstitial cells. IGFBP-1 mRNA levels also increased in cortical tubular cells at each time point tested. Peak induction of IGFBP-3 and -5 was observed at day 3, whereas IGFBP-1 was delayed until day 7. IGFBP-1, -3, and -5 mRNA levels declined by day 14, but remained persistently elevated above control. By immunoperoxidase staining, similar alterations in the pattern of IGFBP-3 and -5 protein expression were observed at each time point. The preferential and site-specific increase in IGFBP-1, -3, and -5 suggest that these IGFBPs may regulate the local autocrine and/or paracrine actions of IGF-I and contribute to the pathogenesis of the early manifestations of diabetic nephropathy.  相似文献   
38.
自体造血干细胞移植治疗恶性血液病   总被引:2,自引:0,他引:2  
为探讨恶性血液病的有效治疗方法,应用自体骨髓移植(ABMT)38例,自体外周血造血干细胞移植(ABSCT)13例,自体外周血造血干细胞与自体骨髓联合移植15例。治疗白血病54例,恶性淋巴瘤11例,多发性骨髓瘤1例。外周血造血干细胞采用化疗加多抗甲素或C—CSF动员。移植物采用微波、阿克拉霉素净化处理。结果:两组动员方案均有良好动员效果。ABSCT组及联合移植组造血功能恢复比ABMT组快(P<0.05),合并症少。66例中,45例仍呈持续缓解(CCR),中位CCR时间32(5~98)个月,复发21例。3年无病生存率及复发率分别为68.5%及26.1%。结果表明:自体造血干细胞移植是根治恶性血液病的有效手段。ABSCT及联合移植具有造血功能恢复快,合并症少等优点。微波和阿克拉霉素体外净化移植物是一种简便、有效的净化方法。  相似文献   
39.
  目的  对比观察近视儿童配戴离焦软性接触镜与角膜塑形镜控制近视的有效性和安全性。  方法   回顾性研究2018年1月至2020年9月我院就诊的儿童近视患者临床资料,共75例儿童纳入分析。离焦软镜组:日戴周边离焦软性接触镜的近视儿童30例(60眼),男性10例,女性20例,年龄(9.9±1.00)岁,等效球镜度数(?2.78±0.70)D。角膜塑形镜组:配戴角膜塑形镜的近视儿童45例(90眼),女性30例,男性15例,年龄(9.67±1.11)岁,等效球镜度数(?2.67±0.71)D。两组患儿均已配戴12个月及以上框架眼镜后验配接触镜。随访12个月,对比分析两组近视儿童眼轴变化情况及角膜结膜并发症情况。  结果  两组近视儿童戴框架眼镜期间眼轴增加较快,OrthoK组配前的框架期眼轴增量(0.34±0.09) mm,DISC组配前的框架期眼轴增量(0.37±0.07) mm;换为接触镜后戴接触镜12个月后,OrthoK 组眼轴增量(0.18±0.04) mm;DISC组眼轴增量(0.19±0.05) mm,两组儿童更换近视防控方案后眼轴增量均降低,差异有统计学意义(P<0.05)。两种不同接触镜的眼轴长度增量接近,两者差异无统计学意义(P>0.05)。配戴两种接触镜12个月期间,慢性滤泡性结膜炎发生率角膜塑形镜组为11.20%,离焦软镜组为20.00%,其中离焦软镜组比例略高,但差异无统计学意义(P>0.05)。角膜染色1级发生率角膜塑形镜组为66.70%,离焦软镜组为56.70%;角膜染色2级发生率角膜塑形镜组为17.80%,离焦软镜组为16.70%,其中两种程度的角膜染色角膜塑形镜组比例均略高于离焦软镜,但差异无统计学意义(P>0.05)。接触镜乳头性结膜炎发生率角膜塑形镜组为2.20%,离焦软镜组为10.00%,离焦软镜发生率略高于角膜塑形镜,但差异无统计学意义(P>0.05)。  结论  离焦软镜与角膜塑形镜均可有效控制近视儿童眼轴长度的进展,其控制效果均优于框架眼镜,两种接触镜对眼轴控制效果接近。两种接触镜的角结膜并发症较少,安全性较高。  相似文献   
40.
目的 探讨右美托咪定调控核因子E2相关因子2(Nrf2)/血红素加氧酶1(HO-1)通路对过氧化氢(H2O2)诱导心肌细胞氧化应激损伤的作用。方法 体外培养大鼠H9C2心肌细胞,设置对照组、H2O2组、1μmol右美托咪定+H2O2组、5μmol右美托咪定+H2O2组、10μmol右美托咪定+H2O2组。CCK-8法检测各组H9C2细胞增殖情况;酶联免疫吸附试验(ELISA)检测各组H9C2细胞丙二醛(MDA)、超氧化物歧化酶(SOD)水平;实时荧光定量聚合酶链反应(q RT-PCR)检测各组H9C2细胞Nrf2、HO-1 mRNA相对表达量;Western blotting检测各组H9C2细胞Nrf2、HO-1蛋白相对表达量。结果 与对照组比较,H2O2组H9C2细胞存活率、SOD水平、Nrf2、HO-1 mRNA及蛋白相对...  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