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   4914篇
  免费   708篇
  国内免费   415篇
耳鼻咽喉   49篇
儿科学   420篇
妇产科学   50篇
基础医学   314篇
口腔科学   32篇
临床医学   641篇
内科学   592篇
皮肤病学   41篇
神经病学   83篇
特种医学   180篇
外科学   641篇
综合类   1644篇
预防医学   723篇
眼科学   67篇
药学   231篇
  7篇
中国医学   166篇
肿瘤学   156篇
  2024年   8篇
  2023年   94篇
  2022年   292篇
  2021年   302篇
  2020年   309篇
  2019年   205篇
  2018年   154篇
  2017年   120篇
  2016年   141篇
  2015年   149篇
  2014年   473篇
  2013年   405篇
  2012年   491篇
  2011年   471篇
  2010年   391篇
  2009年   260篇
  2008年   220篇
  2007年   324篇
  2006年   252篇
  2005年   149篇
  2004年   143篇
  2003年   131篇
  2002年   97篇
  2001年   112篇
  2000年   86篇
  1999年   95篇
  1998年   59篇
  1997年   49篇
  1996年   27篇
  1995年   11篇
  1994年   5篇
  1993年   5篇
  1992年   2篇
  1991年   2篇
  1990年   2篇
  1983年   1篇
排序方式: 共有6037条查询结果,搜索用时 31 毫秒
1.
2.
BackgroundFocal liver lesions with spindle cell morphology are rare in the daily practice of pathology. The differential diagnosis is broad, including both tumors and tumor-like lesions. Initial radiologic assessment is sometimes inaccurate. Histopathology is needed to arrive at the correct diagnosis. This study analyzed discrepancies between histopathology and radiologic findings of focal liver lesions with spindle cell morphology.MethodsA six-year retrospective analysis was conducted at a tertiary hospital in Thailand. All focal liver lesions with spindle cell morphology were retrieved. Clinicopathologic features of these cases were analyzed. The pathological diagnosis was rendered primarily based on routine histopathology, using other ancillary studies as an adjunct.Results287 biopsies and 151 resection specimens with focal liver lesions were identified. In 12 (2.7%) cases, tumors or tumor-like lesions with spindle cell morphology were retrieved. A total of five cases had discrepancies between histopathology and radiologic findings. These lesions encompassed primary liver tumors (EBV-associated smooth muscle tumor and leiomyosarcoma); metastatic tumors (gastrointestinal stromal tumor, small cell neuroendocrine carcinoma); and a tumor-like lesion (endometriosis). Several morphologic findings (i.e., cytologic grades, dense and loose areas, intratumoral lymphocytes, distinct perinuclear vacuoles, and hemosiderin) are important clues to diagnose these spindle cell lesions.ConclusionsPathologists play a critical role in diagnosing focal liver lesions with spindle cell morphology, particularly those with limited clinical data at the initial presentation. A thorough evaluation of histomorphology on routine hematoxylin and eosin-stained slides is essential for correct diagnosis.  相似文献   
3.
AimGenomic-based ancillary assays including immunohistochemistry (IHC) for BRCA-1 associated protein-1 (BAP1) and methylthioadenosine phosphorylase (MTAP), and fluorescence in situ hybridization (FISH) for CDKN2A are effective for differentiating pleural mesothelioma (PM) from reactive mesothelial proliferations. We previously reported a combination of MTAP and BAP1 IHC effectively distinguishes sarcomatoid PM from fibrous pleuritis (FP). Nevertheless, cases of sarcomatoid PM with desmoplastic features (desmoPM) are encountered where the IHC assessment is unclear.Methods and resultsWe evaluated assessment of MTAP IHC, BAP1 IHC, and CDKN2A FISH in 20 desmoPM compared to 24 FP. MTAP and BAP1 IHC could not be assessed in 11 (55 %) and 10 (50 %) cases, respectively, due to loss or faint immunoreactivity of internal positive control cells, while CDKN2A FISH could be evaluated in all cases. The sensitivities for MTAP loss, BAP1 loss, and CDKN2A homozygous deletion in desmoPM were 40 %, 10 %, and 100 %. A combination of MTAP loss and BAP1 loss yielded 45 % of sensitivity.ConclusionsMTAP IHC is a useful surrogate diagnostic marker in differentiating ordinary sarcomatoid PM from FP, but its effectiveness is limited in desmoPM. CDKN2A FISH is the most effective diagnostic assays with 100 % sensitivity and specificity in discriminating desmoPM from FP in the facilities where the FISH assay is available.  相似文献   
4.
患者女性,65岁,局部进展期胰腺癌伴门静脉、肠系膜上静脉和肠系膜上动脉侵犯,经6个周期奥沙利铂+氟尿嘧啶+伊立替康+亚叶酸钙(FOLFIRINOX)新辅助化疗后,肿瘤评估为部分缓解,但仍属于局部进展期胰腺癌。患者行动脉优先入路、全门静脉系统切除、异体血管置换重建的扩大胰十二指肠切除术,同时运用异体血管体外成形技术。患者术后已无瘤生存28个月。FOLFIRINOX新辅助化疗方案可使部分局部进展期胰腺癌患者疾病达到稳定状态,而异体血管体外成形技术的应用为门静脉系统全切除置换提供了一种新的方法,使患者有机会达到根治性手术切除,从而改善远期预后。  相似文献   
5.
《Injury》2023,54(4):1088-1094
IntroductionDespite the improvements in surgical techniques and the use of prophylactic intravenous antibiotics, the fracture-related infection (FRI) incidence after high-risk tibial plateau fractures remains high. This study aimed to evaluate the clinical effect of the intrawound application of vancomycin on the FRI after high-risk tibial plateau fracture surgery.MethodsA total of 243 patients who underwent high-risk tibial plateau fracture surgery from May 2013 to June 2021 were retrospectively reviewed. Of these, 233 cases were enrolled. Considering the preoperative patient condition, surgeons applied vancomycin powder directly into the surgical site before wound closure in 105 cases (intrawound application of vancomycin powder with preoperative intravenous cephalosporin). The remaining 128 cases served as the control group (preoperative intravenous cephalosporin alone). Clinical data and surgical details were recorded. The Cox proportional hazards regression analysis was used to assess risk factors for FRI. The Kaplan-Meier method and the log rank test illustrated the infection status of patients based on the application of intrawound vancomycin. The primary outcome was an FRI within one year. Secondary outcomes included bacterial culture and vancomycin-related complications.ResultsOur study demonstrated a significant difference in the incidence of FRI between the vancomycin group and the control group (3.8% versus 10.9%; p=0.041). Multivariable Cox regression showed the intrawound application of vancomycin powder decreased the rate of FRI. There were no complications related to intrawound vancomycin observed during follow-up. The presence of Gram-positive FRI was higher in the control group compared with the vancomycin group.ConclusionsIntrawound application of vancomycin was associated with a significant lower rate of FRI after high-risk tibial plateau fracture surgery compared to the control group.  相似文献   
6.
ObjectiveTo detect the Epstein-Barr virus (EBV) viral load of children after hematopoietic stem cell transplantation (HSCT) using chip digital PCR (cdPCR).MethodsThe sensitivity of cdPCR was determined using EBV plasmids and the EBV B95-8 strain. The specificity of EBV cdPCR was evaluated using the EBV B95-8 strain and other herpesviruses (herpes simplex virus 1, herpes simplex virus 2, varicella zoster virus, human cytomegalovirus, human herpesvirus 6, and human herpesvirus 7). From May 2019 to September 2020, 64 serum samples of children following HSCT were collected. EBV infection and the viral load of serum samples were detected by cdPCR. The epidemiological characteristics of EBV infections were analyzed in HSCT patients.ResultsThe limit of detection of EBV cdPCR was 110 copies/mL, and the limit of detection of EBV quantitative PCR was 327 copies/mL for the pUC57-BALF5 plasmid. The result of EBV cdPCR was up to 121 copies/mL in the EBV B95-8 strain, and both were more sensitive than that of quantitative PCR. Using cdPCR, the incidence of EBV infection was 18.75% in 64 children after HSCT. The minimum EBV viral load was 140 copies/mL, and the maximum viral load was 3,209 copies/mL using cdPCR. The average hospital stay of children with EBV infection (184 ± 91 days) was longer than that of children without EBV infection (125 ± 79 days), P = 0.026.ConclusionEBV cdPCR had good sensitivity and specificity. The incidence of EBV infection was 18.75% in 64 children after HSCT from May 2019 to September 2020. EBV cdPCR could therefore be a novel method to detect EBV viral load in children after HSCT.  相似文献   
7.
目的探究肝移植术后腹、胸腔感染常见病原菌分布及耐药情况。 方法回顾性分析首都医科大学附属北京朝阳医院肝胆外科2011年1月至2017年12月343例行同种异体原位肝移植术受者临床资料,分析围手术期腹腔和胸腔感染情况、常见病原菌及耐药情况。腹、胸腔感染常见病原菌分布比较采用卡方检验,P<0.05为差异有统计学意义。 结果343例肝移植受者中,围手术期48例单独发生腹腔感染,61例单独发生胸腔感染,10例同时发生腹、胸腔感染,15例因感染导致死亡。发生腹腔感染的受者腹腔引流液共培养出106株病原菌,屎肠球菌、鲍曼不动杆菌和溶血葡萄球菌为最常见的病原菌,分别占19.8%(21/106)、15.1%(16/106)和11.3%(12/106)。发生胸腔感染的受者胸腔引流液共培养出99株病原菌,鲍曼不动杆菌、铜绿假单胞菌和肺炎克雷伯菌为最常见的病原菌,分别占26.3%(26/99)、18.2%(18/99)和17.2%(17/99)。腹、胸腔感染常见病原菌(鲍曼不动杆菌、屎肠球菌、溶血葡萄球菌、铜绿假单胞菌和肺炎克雷伯菌)感染分布差距均有统计学意义(χ2=3.92、135.62、162.14、11.09和6.81,P均<0.05)。药敏试验结果示鲍曼不动杆菌对青霉素类、喹诺酮类和碳青霉烯类抗生素均已耐药(>90%),仅对替加环素较为敏感(27%);铜绿假单胞菌对碳青霉烯类和替加环素耐药率最低(11%);肺炎克雷伯菌对阿米卡星和替加环素耐药率最低(6%);革兰阳性球菌(屎肠球菌和溶血葡萄球菌)对替考拉宁、万古霉素和替加环素最为敏感;真菌对氟康唑最敏感。 结论肝移植术后围手术期腹、胸腔感染发生率均较高,且病原学分布各有特点,术后应积极反复进行相关病原学检查,并根据药敏试验结果合理使用抗生素。  相似文献   
8.
目的探讨miR-126在肝癌中表达的临床意义及其与临床特征、预后的关系。 方法收集118例肝癌组织、癌旁组织(距肿瘤切缘5 cm的组织)及正常组织(距肿瘤切缘10 cm的组织)标本,应用实时PCR检测miR-126的表达。分析miR-126的表达与肝癌临床病理特征及预后的关系。应用SPSS 19.0统计软件处理数据,无病生存率行χ2检验;肝组织中miR-126的表达以( ±s)表示,行t检验。采用Kaplan-Merier法进行无病生存期分析,运用Cox回归进行单因素及多因素生存分析。P<0.05差异有统计学意义。 结果miR-126在肝癌组织中的表达量明显低于癌旁组织及正常组织,在癌旁组织中的表达量明显低于正常组织,比较差异具有统计学意义(P<0.05)。miR-126在肝癌组织中的表达与TNM分期、转移有关(P<0.05),而与性别、年龄、肿瘤直径、组织类型、肝炎病史、肿瘤数量无关(P>0.05)。COX多因素回归模型分析显示,转移、miR-126表达是影响肝癌患者预后的独立因素,其中miR-126低表达患者复发、转移、死亡的风险是miR-126高表达的1.528倍(95% CI: 0.947~3.002, P=0.022)。 结论miR-126表达下调参与了肝癌发生发展过程,对判断肝癌的恶性程度及预测预后有一定的临床价值。  相似文献   
9.
目的 研究机械通气下使用密闭式吸痰的婴幼儿吸痰前不常规提高吸氧浓度对患儿氧合的影响。 方法 通过对64例婴幼儿(192次吸痰操作),吸痰前不进行提高氧浓度的操作进行观察,分别记录患儿吸痰前平静时、吸痰中、吸痰后1min时患儿SpO2的值和SpO2恢复至平静时所需的时间。 结果 吸痰前不提高氧浓度,患儿在吸痰时及吸痰后SpO2相对于吸痰前变化不明显。吸痰后SpO2恢复至平静时的时间为18.00(5.25-30.00)s。 结论 吸痰前SpO2稳定,并排除痉咳、心脏分流等原因的患儿,密闭式吸痰前没有必要常规给予提高吸氧浓度的操作。  相似文献   
10.
The aim of this study was to assess the intra- and inter-rater reliability/agreement of the lateral abdominal muscle (LAM) stiffness and thickness measurements at rest and during contraction and to determine the relationship between the superficial fat thickness and the LAM stiffness measurements. LAM stiffness and thickness were measured using supersonic shear wave elastography (SSI) in pediatric participants. The reliability of LAM stiffness and thickness measurements ranged from moderate to excellent. There was an inverse correlation between fat thickness and between-rater difference in the resting external oblique stiffness (r > –0.37) and the contracted external and internal oblique stiffness (r > –0.40). SSI is a reliable method for assessing LAM stiffness and thickness in pediatric populations. To remove potential systematic errors: (i) the first round of measurements should be performed to familiarize patients with procedures; (ii) the examiner should pay more attention while performing LAM measurements on the opposite side of the body.  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