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   49837篇
  免费   7281篇
  国内免费   3117篇
耳鼻咽喉   1023篇
儿科学   1001篇
妇产科学   659篇
基础医学   4080篇
口腔科学   1207篇
临床医学   7002篇
内科学   7417篇
皮肤病学   892篇
神经病学   2653篇
特种医学   1866篇
外国民族医学   10篇
外科学   6311篇
综合类   8577篇
现状与发展   13篇
一般理论   1篇
预防医学   4369篇
眼科学   1435篇
药学   4745篇
  57篇
中国医学   2848篇
肿瘤学   4069篇
  2024年   248篇
  2023年   1234篇
  2022年   2001篇
  2021年   2725篇
  2020年   2769篇
  2019年   1575篇
  2018年   2075篇
  2017年   2047篇
  2016年   2056篇
  2015年   2757篇
  2014年   3384篇
  2013年   3460篇
  2012年   3736篇
  2011年   3759篇
  2010年   3104篇
  2009年   2835篇
  2008年   2478篇
  2007年   2309篇
  2006年   2284篇
  2005年   1967篇
  2004年   1259篇
  2003年   1125篇
  2002年   885篇
  2001年   846篇
  2000年   755篇
  1999年   856篇
  1998年   650篇
  1997年   676篇
  1996年   607篇
  1995年   594篇
  1994年   410篇
  1993年   268篇
  1992年   282篇
  1991年   307篇
  1990年   206篇
  1989年   245篇
  1988年   182篇
  1987年   162篇
  1986年   155篇
  1985年   131篇
  1984年   116篇
  1983年   90篇
  1982年   93篇
  1981年   59篇
  1980年   61篇
  1979年   42篇
  1978年   46篇
  1977年   45篇
  1975年   43篇
  1972年   31篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
目的观察鼻窦内镜术(endoscopic sinu ssurgery,ESS)对慢性鼻窦炎伴支气管哮喘患者哮喘发作的影响。方法对210例慢性鼻窦炎患者施行ESS术,其中伴有支气管哮喘病史者42例(20.0%)。210例患者均于术前、术后采用酶联免疫吸附测定法(ELISA)检测外周血单个核细胞(PBMC)培养上清液中的白细胞介素4(IL-4),干扰素γ(IFN-γ),可溶性白细胞介素2受体(sIL-2R)和可溶性IgE低亲和力受体(solube CD23,sCD23)的含量,并与20例正常对照组进行比较。通过主观和客观标准评定42例患者哮喘发作及对皮质类固醇的耐受状况,并对术后患者进行为期1年(10例)和3年(32例)的随访。结果鼻窦炎合并支气管哮喘患者术前PBMC培养上清液中IL-4,sIL-2R、sCD23含量较对照组显著升高,而IFN-γ含量较对照组显著减少。术后IL-4、sIL-2R、sCD23含量较对照组显著降低,而IFN-γ含量显著增高。术后哮喘改善水平由随访术后1年的45%提高到术后3年的70%。42例中32例(76%)哮喘发作次数明显减少,术前长期服用类固醇的2l例中,14例(67%)减少了对口服类固醇的使用。结论ESS对慢性鼻窦炎伴支气管哮喘患者的治疗有较满意的远期疗效。ESS能调节IL-4、IFN-γ sIL-2R、sCD23水平,降低哮喘的发作频率和对类固醇的依赖。  相似文献   
82.
儿童无症状尿检异常IgA肾病的临床病理和预后分析   总被引:2,自引:0,他引:2  
目的 探讨儿童无症状尿检异常的IgA肾病的临床病理特征和预后。 方法 对54例IgA肾病儿童的临床和病理特征进行分析。根据起病时有无临床症状分为无症状尿检异常组和有症状肾炎组。组织病理学分级参照Lee氏和Katafuchi氏半定量积分法。 结果 无症状尿检异常组18例,有症状肾炎组36例。有症状肾炎组尿蛋白量(24 h)明显高于无症状尿检异常组[(2.3±2.2) g比(0.4±0.3) g,P < 0.05]。无症状尿检异常的IgA肾病儿童表现为镜下血尿者,87%有尿微量白蛋白增高。无症状尿检异常IgA肾病患儿病理表现以Lee 氏Ⅰ~Ⅱ级为主,2例表现为Lee氏Ⅳ~Ⅴ级和 5例发生Katafuchi Ⅱ~Ⅲ级肾小管间质病变。有症状肾炎组Lee氏病理分级以Ⅱ~Ⅲ级为主,两者病理分级分布差异无统计学意义(P > 0.05)。全组患儿平均随访(26.9±8.8)月后,1例病理为Lee 氏Ⅴ级患儿进入终末期肾衰竭,其余患儿Scr均无升高1倍以上。 结论 无症状尿检异常的儿童IgA肾病虽临床症状轻微,但可出现病理损害严重的病例,并影响其预后。  相似文献   
83.
Objectives Cutaneous burns are dynamic injuries with a central zone of necrosis surrounded by a zone of ischemia. Conversion of this ischemic zone to full necrosis over the days following injury is due in part to highly reactive oxygen radicals. Curcumin is a component of the Oriental spice turmeric that has been shown to have antioxidant and antiapoptotic properties. The authors hypothesized that treatment of burns with curcumin would reduce the conversion of the ischemic zone to full necrosis. Methods This was a randomized controlled experiment. Twenty Sprague‐Dawley rats were used. Two burns were created on each animal's dorsum using a brass comb with four rectangular prongs preheated in boiling water and applied for 30 seconds, resulting in four rectangular 10 × 20–mm full‐thickness burns separated by three 5 × 20–mm unburned interspaces (zone of ischemia). Animals were randomized to curcumin or vehicle by oral gavage 30 minutes before injury and at 24, 48, and 72 hours after injury. Wounds were observed at one, two, and three days after injury for visual evidence of necrosis in the unburned interspaces. Full‐thickness biopsy specimens from the interspaces were evaluated with hematoxylin and eosin staining seven days after injury for evidence of necrosis. The percentage of interspaces that progressed to necrosis was compared with chi‐square tests. Results Forty comb burns with 120 unburned interspaces were created, evenly distributed between curcumin and vehicle alone. The percentage of interspaces that progressed to full‐thickness necrosis at one, two, three, and seven days after injury in the curcumin and vehicle groups were 30% versus 63% (p = 0.003), 30% versus 70% (p < 0.001), 63% versus 95% (p = 0.02), and 63% versus 95% (p = 0.02), respectively. Conclusions Pretreatment of rats with oral curcumin followed by once‐daily oral treatment for three days reduced the percentage of unburned skin interspaces that progressed to full necrosis.  相似文献   
84.
Objectives: Little is known about recent trends in U.S. emergency department (ED) visits for acute exacerbation of chronic obstructive pulmonary disease (AECOPD) or about ED management of AECOPD. This study aimed to describe the epidemiology of ED visits for AECOPD and to evaluate concordance with guideline‐recommended care. Methods: Data were obtained from National Hospital Ambulatory Medical Care Survey (NHAMCS). ED visits for AECOPD, during 1993 to 2005, were identified using the International Classification of Diseases, Ninth Revision, Clinical Modification (ICD‐9‐CM) codes. Concordance with guideline recommendations was evaluated using process measures. Results: Over the 13‐year study period, there was an average annual 0.6 million ED visits for AECOPD, and the visit rates for AECOPD were consistently high (3.2 per 1,000 U.S. population; Ptrend = 0.13). The trends in the use of chest radiograph, pulse oximetry, or bronchodilator remained stable (all Ptrend > 0.5). By contrast, the use of systemic corticosteroids increased from 29% in 1993–1994 to 60% in 2005, antibiotics increased from 14% to 42%, and methylxanthines decreased from 15% to <1% (all Ptrend < 0.001). Multivariable analysis showed patients in the South (vs. the Northeast) were less likely to receive systemic corticosteroids (odds ratio [OR] = 0.6; 95% confidence interval [CI] = 0.4 to 0.9). Conclusions: The high burden of ED visits for AECOPD persisted. Overall concordance with guideline‐recommended care for AECOPD was moderate, and some emergency treatments had improved over time.  相似文献   
85.
姜婷  薛茜 《新疆医科大学学报》2010,33(4):422-425,430
目的 系统评价碘盐预防碘缺乏病的效果.方法 计算机检索Cochrane Central Register of Controlled Trial(Cochrane图书馆2009年第4期)、MEDLINE(1966~2009.12)、Ovid Medline(1966~2009.12)、Embase数据库(1986~2009.12)、CBM光盘版(1978~2009.12)、CNKI(1980~2009.12)以及VIP(1989~2009.12),并且追查纳入文献的参考文献.按纳入和排除标准由2名评价者独立选择试验、提取资料,交叉核对并进行方法学质量评估,对同质研究采用RevMan 5.0软件进行Meta分析.结果 共纳入5篇随机对照研究,842例研究对象,儿童组碘盐和空白食盐的甲肿率结果比较无统计学意义[OR=1.19,95%CI(0.74,1.92)],成人组碘盐和其他形式的补碘措施比较,碘盐组甲肿率、甲状腺体积均低于其他形式的补碘组.结论 碘盐能显著改善成人的碘营养状况,副作用还需大量高质量的随机对照试验来验证.  相似文献   
86.
87.
目的 观察电针足三里、天枢穴为主治疗急腹痛的疗效.方法 对100例急性腹痛患者采用电针足三里、天枢穴治疗,观察其临床效果.结果 治愈82例,治愈率82%;好转18例,好转率18%;总有效率100%.结论 电针足三里、天枢穴为主治疗急性腹痛,止痛迅速,简便易行,无副作用.  相似文献   
88.
目的评价改良提上睑肌缩短术矫治上睑下垂的效果。方法采用改良提上睑肌缩短术[此改良术式与常规术式不同之处在于增加分离提上睑肌腱膜的长度(22mm)和宽度(16mm),腱膜在睑板上固4对缝线,以增加其牢固度],共治疗上睑下垂57例68眼,其中轻度13例13眼,中度38例47眼,重度6例8眼。结果术后4~36个月随访,治愈48例59眼,欠矫9例9眼,无过矫病例。结论该提上睑肌缩短术与常规手术比较有改进,术后的睑缘高度易保持在上方角膜缘,弧度与健侧对称,不易形成眼角畸形,能较好提高矫治效果。  相似文献   
89.
Chronic wounds create a formidable clinical problem resulting in considerable morbidity and healthcare expenditure. The etiology for wound healing impairment appears to be multifactorial; however, ischemia is a common factor in most types of chronic wounds. Ideal therapy for such wounds would be to correct deficiencies in growth factors and matrix components and provide cellular precursors required for timely wound closure. We hypothesized that stromal progenitor cell (SPC) therapy could correct the ischemic wound-healing defect through both direct and indirect mechanisms. To test this hypothesis, we used the ischemic rabbit ear model of chronic wound healing. We found that treatment of the wounds with SPCs was able to reverse the ischemic wound-healing impairment, with improved granulation tissue formation and reepithelialization compared with vehicle or bone marrow mononuclear cell controls. In vitro, SPCs were found to produce factors involved in angiogenesis and reepithelialization, and extracellular matrix components, providing evidence for both direct and indirect mechanisms for the observed correction of the healing impairment in these wounds. Treatment of ischemic wounds with SPCs can dramatically improve wound healing and provides a rationale for further studies focused on SPCs as a potential cellular therapy in impaired wound healing.  相似文献   
90.
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