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   2051篇
  免费   254篇
  国内免费   124篇
儿科学   3篇
妇产科学   1篇
基础医学   145篇
口腔科学   1篇
临床医学   129篇
内科学   649篇
皮肤病学   3篇
神经病学   3篇
特种医学   124篇
外国民族医学   3篇
外科学   468篇
综合类   279篇
预防医学   13篇
药学   66篇
中国医学   13篇
肿瘤学   529篇
  2024年   5篇
  2023年   79篇
  2022年   101篇
  2021年   135篇
  2020年   180篇
  2019年   106篇
  2018年   61篇
  2017年   102篇
  2016年   91篇
  2015年   93篇
  2014年   130篇
  2013年   111篇
  2012年   101篇
  2011年   121篇
  2010年   117篇
  2009年   79篇
  2008年   107篇
  2007年   93篇
  2006年   95篇
  2005年   95篇
  2004年   66篇
  2003年   60篇
  2002年   56篇
  2001年   48篇
  2000年   54篇
  1999年   43篇
  1998年   17篇
  1997年   13篇
  1996年   14篇
  1995年   16篇
  1994年   12篇
  1993年   9篇
  1992年   4篇
  1991年   2篇
  1990年   3篇
  1989年   2篇
  1988年   3篇
  1987年   2篇
  1986年   1篇
  1980年   2篇
排序方式: 共有2429条查询结果,搜索用时 296 毫秒
1.
PurposeTo investigate the safety and efficacy of an aqueous polyethylene glycol-based liquid embolic agent, Embrace Hydrogel Embolic System (HES), in the treatment of benign and malignant hypervascular tumors.Materials and MethodsA prospective, single-arm, multicenter study included 8 patients, 5 males and 3 females, with a median age of 58.5 years (30–85 years), who underwent embolization in 8 tumors between October 2019 and May 2020. Technical success was defined as successful delivery of HES to the index vessel, with disappearance of >90% of the targeted vascular enhancement or, for portal vein embolization, occlusion of the portal branches to the liver segments for future resection. The volume of HES administered, ease of use (5 point Likert scale), administration time, and adverse events (AEs) were recorded. Evaluation was performed at 7, 30, and 90 days via clinical assessment and blood testing, and follow-up imaging was performed at 30 days.ResultsEight patients were enrolled, and 10 embolizations were performed in 8 lesions. Tumors included hepatocellular carcinoma (n = 4), renal angiomyolipoma (n = 3), and intrahepatic cholangiocarcinoma (n = 1). Technical success was 100%, and the average ease of use was 3.3 ± 1.0 SD. The HES delivery time was 1–28 minutes (median, 16.5 minutes), and the HES volume injected was 0.4–4.0 mL (median, 1.3 mL). All patients reached 30-day follow-up with imaging, and 6 patients reached 90-day follow-up. There were 3 serious AEs in 2 patients that were unrelated to the embolic agent.ConclusionHES resulted in a 100% embolization technical success rate. The product ease of use was acceptable, and no target vessel recanalization was noted on follow-up imaging at 30 days.  相似文献   
2.
BackgroundA comprehensive re-evaluation on the role of trans-arterial chemoembolization (TACE) in patients with intrahepatic cholangiocarcinoma.MethodsA thorough database searching was performed in PubMed, EMBASE, and the Cochrane Library. Eligible studies were restricted to comparative studies between TACE and non-TACE cohorts. RevMan5.3 software and Stata 13.0 software were used for statistical analyses. The primary endpoint of our study was long-term survival.ResultsA total of 11 studies with 2036 patients were finally identified. Pooled results revealed that patients receiving TACE had a significantly better overall survival (OS) versus those without TACE (P < 0.05). Subgroup analyses were performed according to different types of TACE. Prophylactic post-surgical TACE (PPTACE) was associated with a significantly better OS versus those without PPTACE (P < 0.05). Palliative TACE (PTACE) also achieved a significantly better OS compared with those with supportive treatment (ST) only (P < 0.00001). However, TACE had no impact on disease-free survival (P = 0.87) and was less effective than surgical resection (P = 0.003).ConclusionPPTACE has a remarkable impact on OS versus those with surgical resections only and should be regularly performed. Regarding patients with unresectable disease, apart from conventional ST, adjuvant PTACE is also recommended. Upcoming prospective randomized controlled trials are warranted for further validation.  相似文献   
3.
Tumor tissue is composed of tumor cells and tumor stroma. Tumor stroma contains various immune cells and non-immune stromal cells, forming a complex tumor microenvironment which plays pivotal roles in regulating tumor growth. Recent successes in immunotherapies against tumors, including immune checkpoint inhibitors, have further raised interests in the immune microenvironment of liver carcinoma. The immune microenvironment of tumors is formed because of interactions among tumor cells, immune cells and non-immune stromal cells, including fibroblasts and endothelial cells. Different patterns of immune microenvironment are observed among different tumor subtypes, and their clinicopathological significance and intertumor/intratumor heterogeneity are being intensively studied. Here, we review the immune microenvironment of hepatocellular carcinoma, intrahepatic cholangiocarcinoma and liver metastasis of colorectal adenocarcinoma, focusing on its histopathological appearance, clinicopathological significance, and relationship with histological and molecular classifications. Understanding the comprehensive histopathological picture of a tumor immune microenvironment, in addition to molecular and genetic approaches, will further potentiate the effort for precision medicine in the era of tumor-targeting immunotherapy.  相似文献   
4.
Background:We aim to evaluate the efficiency of Raman spectroscopy (RS) in diagnosing suspected patients with intrahepatic cholangiocarcinoma (ICC), manifested by diagnostic sensitivity, specificity, and accuracy.Methods:We will research widely the articles concerning the use of RS in ICC through authenticated database including PubMed/Medline, EMBASE, Web of Science, Ovid, Web of Knowledge, Cochrane Library, and CNKI between January 2012 and November 2020, retrieving at least 1500 spectra with strict criteria. This study will be carried out in accordance to Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. We are going to summarize the test performance using random effects models.Results:Based on the pooled sensitivity, specificity, and diagnostic accuracy, we intend to provide the relative diagnostic efficiency in ICC through RS.Conclusion:Through this systematic review and meta-analysis, we intend to provide the pooled sensitivity, specificity and diagnostic accuracy of RS in the diagnosis of suspected ICC. Other parameters like positive likelihood ratios (LR), negative LR, diagnostic odds ratio (DOR), and area under curve (AUC) of the summary receiver operating characteristics (SROC) curve will also be calculated and related figures will be drawn to help illustrate the efficacy of RS in the diagnosis of ICC.  相似文献   
5.
Herpesvirus entry mediator (HVEM) displays dual signals in T-cell activation according to the ligands and intracytoplasmic effectors it interacts with. High HVEM expression may play an immunosuppressive role in several malignancies. The present study investigated the clinical impact of HVEM on intrahepatic cholangiocarcinoma (ICC), including its prognostic value, and association with clinicopathological features and immune status. The clinical data of 102 consecutive patients with ICC who underwent surgical treatment from January 2012 to December 2017 were collected. The expression of HVEM and different types of tumor-infiltrating lymphocytes (TILs) were investigated in ICC tissue samples by immunohistochemical staining. HVEM expression was detected in the tumor tissues of 92 (90.2%) patients with ICC. Patients with high HVEM expression were more likely to have increased peripheral blood lymphocyte (PBL) concentrations (P=0.031), decreased CEA (P=0.036), low TNM stage (P=0.043) and high frequencies of small-duct histological type (P=0.021) and BAP1 retained expression (P=0.010). Survival analysis showed that high HVEM expression was a favorable independent predictor of overall postoperative survival (P=0.034, hazard ratio=0.486, 95% confidence interval=0.249–0.945). In addition, no significant association of HVEM expression with CD4+ (P=0.512), CD8+ (P=0.750) or CD45RO+ (P=0.078) TILs was identified in the ICC tissues. These results indicate that HVEM may serve as a favorable prognostic marker for ICC. Furthermore, co-stimulatory signals from HVEM may play a dominant role in the progression of ICCs, which can be explained by an increase in the number of PBLs rather than a change in the number of TILs. However, the function of the HVEM network in ICC progression is complex and requires further study.  相似文献   
6.
PurposeTo investigate the safety and efficacy of percutaneous or open irreversible electroporation (IRE) in a prospective cohort of patients with locally advanced, unresectable perihilar cholangiocarcinoma (PHC).Materials and MethodsIn a multicenter Phase I/II study, patients with unresectable PHC due to extensive vascular involvement or N2 lymph node metastases or local recurrence after resection for PHC were included and treated by open or percutaneous IRE combined with palliative chemotherapy (current standard of care). The primary outcome was the number of major adverse events occurring within 90 d after IRE (grade ≥3), and the upper limit was predefined at 60%. Secondary outcomes included technical success rate, hospital stay, and overall survival (OS).ResultsTwelve patients (mean age, 63 y ± 12) were treated with IRE. The major adverse event rate was 50% (6 of 12 patients), and no 90-d mortality was observed. All procedures were technically successful, with no intraprocedural adverse events requiring additional interventions. The median OS from diagnosis was 21 mos (95% confidence interval, 15–27 mos), with a 1-y survival rate of 75% after IRE.ConclusionsPercutaneous IRE in selected patients with locally advanced PHC seems feasible, with a major adverse event rate of 50%, which was below the predefined upper safety limit in this prospective study. Future comparative research exploring the efficacy of IRE is warranted.  相似文献   
7.
目的探究血管内皮细胞生长因子(VEGF)及其受体对肝内胆管细胞癌(ICC)细胞生长调控的作用机制。 方法Western blotting检测VEGF在12例ICC患者肿瘤组织和癌旁正常组织中的表达水平。采用外源性重组人源VEGF(rhVEGF)处理ICC细胞株Huh28后,采用细胞计数检测细胞生长情况,5-溴脱氧尿嘧啶核苷(BrdU)实验检测细胞增殖,流式细胞术检测细胞凋亡。Western blotting检测rhVEGF处理后Huh28细胞中VEGF受体VEGFR1及VEGFR2的表达情况。使用特异性抗体分别阻断VEGFR1及VEGFR2,通过ELISA法检测细胞的凋亡水平。采用慢病毒shRNA构建稳定敲低VEGFR2的ICC细胞株Huh28-shVEGFR2(实验组)和对照细胞株Huh28-shNC(对照组)。采用Huh28-shVEGFR2及Huh28-shNC细胞在10只裸鼠中构建皮下瘤模型,观察肿瘤的生长情况。 结果VEGF在ICC肿瘤组织中蛋白表达水平上调,显著高于癌旁正常组织(P<0.01)。外源性rhVEGF可以促进Huh28细胞生长,抑制细胞凋亡,而对细胞增殖能力无明显影响。rhVEGF处理后Huh28细胞中磷酸化的VEGFR1及VEGFR2表达水平升高(P<0.05)。VEGFR2抗体可以显著逆转rhVEGF介导的抗凋亡作用(P<0.05),而VEGFR1抗体则无明显效果。皮下瘤模型结果显示,与对照组相比,肿瘤生长在实验组中受到显著抑制,差异有统计学意义(P<0.05)。 结论VEGF是通过VEGFR2依赖的信号通路抑制ICC细胞凋亡,从而促进ICC细胞生长。  相似文献   
8.
目的 探讨腹腔镜根治性切除治疗肝门部胆管癌的可行性及安全性。方法 回顾性分析2013年5月至2018年5月在川北医学院附属医院行根治性手术治疗并经病理学检查证实的15例肝门部胆管癌病人的临床资料,分析术中及术后情况,并随访观察。结果 15例肝门部胆管癌病人中13例行完全腹腔镜手术,2例病人中转开放手术。手术时间为(404.3±62.8)min,术中出血(502.0±133.8)mL,术后住院时间为(9.6±2.7)d,术后首次排气时间为(3.2±0.8)d。术后淋巴结检出数目为(9.5±2.6)枚,1例发现N2淋巴结转移。术后发生胆漏1例,大量腹腔积液1例,切口脂肪液化1例,均经保守治疗后好转出院。所有病人均获得随访,截至2018年5月,随访时间为6~60个月,死亡4例。结论 通过术前充分评估及术中探查制定相应手术策略,并且在严格掌握手术适应证的前提下,由具备丰富腹腔镜手术经验的医生主持操作,腹腔镜技术应用于肝门部胆管癌病人相对安全、可行。  相似文献   
9.
IntroductionMajor hepatectomy (MH) is often needed in the curative management of intrahepatic cholangiocarcinoma (IHCC) and colorectal liver metastases (CRLM). While similar outcomes could be expected after MH for IHCC and CRLM, outcomes seem worse after MH for IHCC. A better understanding of such differences might help improving perioperative outcomes but comprehensive analysis are lacking.MethodsAll patients undergoing curative intent MH for IHCC or CRLM from 2003 to 2009 were included from two dedicated multi-institutional datasets. Preoperative management and short-term outcomes after MH were first compared. Independent predictors of postoperative mortality and morbidity were identified.ResultsAmong 827 patients, 333 and 494 patients underwent MH for IHCC and CRLM, respectively. Preoperative portal vein embolization was more frequently performed in the CRLM group (p < 0.001). MH in the IHCC group required more extended resection (p < 0.001). Postoperative mortality and severe morbidity rates were significantly higher in the IHCC group (7.2% vs. 1.2% and 29.7% vs. 11.1%, p < 0.001, respectively). Main causes for mortality were postoperative liver failure and deep surgical site infection. MH for IHCC was an independent risk factor for mortality (p < 0.001) and severe morbidity (p < 0.001). After propensity score matching (212 patients in each group), the aforementioned differences regarding outcomes remained statistically significant.ConclusionThis study suggests that IHCC patients are inherently more at risk after MH as compared to CRLM patients. Considering that postoperative liver failure was the most frequent cause of death, preoperative planning might have been inadequate in the setting of IHCC while more complex/extended resections should be expected.  相似文献   
10.
目的:研究斑蝥提取物(cantharis extract,CTE)体外诱导人胆管癌QBC939细胞凋亡作用及其对细胞周期分布的影响。方法:体外培养人胆管细胞癌QBC939细胞,CTE作用于QBC939细胞48小时,利用CCK-8法检测QBC939细胞增殖率并计算半数抑制浓度(IC50);光学显微镜下观察细胞形态的改变;AnnexinⅤ/PI双染法检测细胞凋亡情况;用PI染色检测对QBC939细胞周期分布的影响;Western blot法检测细胞凋亡相关蛋白及细胞周期相关蛋白表达变化。结果:CTE显著抑制QBC939细胞增殖,呈浓度及时间依赖性,处理48小时的IC50为4.16μg/ml。经光学显微镜下观察可见随着药物浓度增加,细胞密度减少,游离变圆的细胞明显增多。AnnexinⅤ/PI双染流式凋亡检测示,随着药物浓度的增加,凋亡细胞数量逐渐增加,药物处理组(1.25μg/ml、2.5μg/ml、5.0μg/ml)的细胞凋亡率分别为(9.52±1.01)%、(15.62±1.88)%、(46.03±4.88)%,与对照组(4.59±0.43)%比较,差异有统计学意义(P<0.05)。PI检测细胞周期示,CTE能将QBC939细胞周期阻滞在G2/M期,随药物浓度增加而增加,G2/M期细胞比例逐渐增加,与对照组比较差异有统计学意义,而G1期细胞比例逐渐减少。Western blot检测示,CTE处理组细胞增殖相关蛋白增殖细胞核抗原(PCNA)表达降低,相对蛋白表达量与对照组比较,差异有统计学意义(P<0.05);Bcl-2家族蛋白Bax和Bid表达增加,而Bcl-2、Mcl-1表达降低,抑制凋亡蛋白家族蛋白Survivin表达显著下降,凋亡相关蛋白半胱氨酸蛋白水解酶3(Caspase-3)表达下降,与对照组比较CTE处理组上述相对蛋白表达量差异有统计学意义(P<0.05);CTE处理组细胞周期相关蛋白Chk1表达无显著改变,相对蛋白表达量与对照组比较差异无统计学意义(P<0.05),磷酸化的Chk1蛋白及p53蛋白表达逐渐增加,相对蛋白表达量与对照组比较差异有统计学意义(P<0.05)。结论:CTE显著抑制QBC939细胞增殖,诱导QBC939细胞凋亡,其可能机制与CTE调节凋亡相关蛋白表达,同时调节肿瘤细胞周期相关。  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