全文获取类型
收费全文 | 18634篇 |
免费 | 1313篇 |
国内免费 | 364篇 |
专业分类
耳鼻咽喉 | 105篇 |
儿科学 | 542篇 |
妇产科学 | 314篇 |
基础医学 | 1054篇 |
口腔科学 | 270篇 |
临床医学 | 3780篇 |
内科学 | 2539篇 |
皮肤病学 | 141篇 |
神经病学 | 1820篇 |
特种医学 | 1101篇 |
外国民族医学 | 2篇 |
外科学 | 3119篇 |
综合类 | 2466篇 |
现状与发展 | 3篇 |
预防医学 | 936篇 |
眼科学 | 205篇 |
药学 | 1024篇 |
15篇 | |
中国医学 | 361篇 |
肿瘤学 | 514篇 |
出版年
2024年 | 59篇 |
2023年 | 454篇 |
2022年 | 795篇 |
2021年 | 976篇 |
2020年 | 911篇 |
2019年 | 739篇 |
2018年 | 723篇 |
2017年 | 732篇 |
2016年 | 697篇 |
2015年 | 654篇 |
2014年 | 1407篇 |
2013年 | 1290篇 |
2012年 | 1067篇 |
2011年 | 1114篇 |
2010年 | 961篇 |
2009年 | 868篇 |
2008年 | 840篇 |
2007年 | 784篇 |
2006年 | 729篇 |
2005年 | 629篇 |
2004年 | 474篇 |
2003年 | 412篇 |
2002年 | 379篇 |
2001年 | 313篇 |
2000年 | 254篇 |
1999年 | 195篇 |
1998年 | 177篇 |
1997年 | 194篇 |
1996年 | 151篇 |
1995年 | 162篇 |
1994年 | 116篇 |
1993年 | 101篇 |
1992年 | 109篇 |
1991年 | 95篇 |
1990年 | 81篇 |
1989年 | 72篇 |
1988年 | 82篇 |
1987年 | 57篇 |
1986年 | 64篇 |
1985年 | 77篇 |
1984年 | 62篇 |
1983年 | 37篇 |
1982年 | 51篇 |
1981年 | 32篇 |
1980年 | 22篇 |
1979年 | 24篇 |
1978年 | 21篇 |
1977年 | 18篇 |
1976年 | 14篇 |
1975年 | 9篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
1.
2.
3.
4.
IntroductionPredicting pathological complete response (pCR) for patients receiving neoadjuvant chemotherapy (NAC) is crucial in establishing individualized treatment. Whole-slide images (WSIs) of tumor tissues reflect the histopathologic information of the tumor, which is important for therapeutic response effectiveness. In this study, we aimed to investigate whether predictive information for pCR could be detected from WSIs.Materials and methodsWe retrospectively collected data from four cohorts of 874 patients diagnosed with biopsy-proven breast cancer. A deep learning pathological model (DLPM) was constructed to predict pCR using biopsy WSIs in the primary cohort, and it was then validated in three external cohorts. The DLPM could generate a deep learning pathological score (DLPs) for each patient; stromal tumor-infiltrating lymphocytes (TILs) were selected for comparison with DLPs.ResultsThe WSI feature-based DLPM showed good predictive performance with the highest area under the curve (AUC) of 0.72 among the cohorts. Alternatively, the combination of the DLPM and clinical characteristics offered a better prediction performance (AUC >0.70) in all cohorts. We also evaluated the performance of DLPM in three different breast subtypes with the best prediction for the triple-negative breast cancer (TNBC) subtype (AUC: 0.73). Moreover, DLPM combined with clinical characteristics and stromal TILs achieved the highest AUC in the primary cohort (AUC: 0.82) and validation cohort 1 (AUC: 0.80).ConclusionOur study suggested that WSIs integrated with deep learning could potentially predict pCR to NAC in breast cancer. The predictive performance will be improved by combining clinical characteristics. DLPs from DLPM can provide more information compared to stromal TILs for pCR prediction. 相似文献
5.
《Dental materials》2020,36(1):119-134
ObjectiveThe aim of this systematic review and meta-analysis was to evaluate the effect of surface conditioning methods on the bond strength of industrial indirect composite blocks (ICs).MethodsBased on the PICOS strategy, the Medline via PubMed, Embase and Web of Science (ISI – Web of Knowledge) electronic databases were searched for peer-reviewed articles in both English and Chinese, with no publication year limit. In vitro studies evaluating the effects of surface conditioning on the bond strength of ICs were selected. The meta-analysis was conducted to calculate the mean difference between surface-conditioned ICs and unconditioned controls. Subgroup analysis was performed to evaluate the different surface conditioning methods, separately for polymer-infiltrated ceramic network (PICN) material and the ICs with dispersed fillers (ICDFs). Meta-analyses were performed with a random-effects model at a significance level of 0.05.Results and SignificanceFrom 802 relevant studies, 25 were selected for full-text analysis. Nineteen studies were eligible for inclusion in this systematic review, whereas 9 studies were included in the meta-analysis. A manual search of the principal periodicals specific to the area resulted in no additional articles. The meta-analysis indicated a significant difference in bond strength between the surface-conditioned ICs and controls under both non-aged and aged conditions. The combination of mechanical and chemical conditioning yielded the highest bond strength of ICs. This meta-analysis suggests that chemical etching followed by a universal primer and alumina air abrasion followed by a silane coupling agent could be considered the best strategy for optimizing the bond strength of PICN materials and ICDFs under aged conditions, respectively. 相似文献
6.
冯莹 《中国实用外科杂志》2020,40(5):531-536
易栓症是外科围手术期静脉血栓栓塞症(VTE)的防治重点。对于接受手术的止凝血障碍病人,需要谨慎评估VTE的个体风险,同时兼顾手术和麻醉的性质、出血障碍类型和严重程度、年龄、体重指数(BMI)、血栓形成史、恶性肿瘤和其他高危共患病。VTE风险应与已知出血障碍病人使用抗凝相关的出血风险平衡。实验室检查有助于发现和判断血栓与出血的病因,对病人的止凝血代偿能力作出评估,并对抗凝药物的合理使用提供依据。对上述病人,建议术后不常规使用药物预防血栓,尤其是血友病病人,但围手术期因子替代和止血药物的过度应用仍存在导致血栓的风险。使用低分子肝素(LMWH)和直接口服抗凝剂前应评估肾小球滤过率。当血小板计数<50×109/L,LMWH短期减量应用可能相对安全,监测抗Хa水平可用于调整中重度血小板减少症病人LMWH的剂量。主要消化道出血停止和重新使用华法林应至少相隔7 d。对于高血栓栓塞风险和术后高出血风险病人,术后当晚和术后第1天减量应用直接口服抗凝剂是一种可取的做法。 相似文献
7.
8.
Purpose: To describe how central venous access devices (CVADs) are utilized for ambulatory oncology patients and to evaluate the rate of complications. Method: Single institution retrospective study of oncology patients with CVADs who received systemic treatment at the Walker Family Cancer Centre (WFCC) between 1 January and 31 December 2018. Results: A total of 480 CVADS were placed in 305 patients, of which 408 (85%) were peripherally inserted central catheters (PICCs) and 72 (15%) were implanted vascular access devices (PORTs). The incidence of early and late complications was 9% and 24%, respectively. For the entire cohort, the rate of venous thromboembolism (VTE) was 16%, of which 9% were CVAD-related thrombosis (CRTs) and 7% were distant VTE. The CRT rates were similar for PICCs and PORTs (9% vs. 7%). A total of 6% of CVADs were complicated by infection (i.e., localized infections and bacteremia), with a total infection rate of 0.43 and 0.26 per 1000 indwelling days for PICCs and PORTs, respectively. The incidence of central line associated bloodstream infections (CLABSI) was greater for PICCs than PORTs, at a rate of 0.22 compared with 0.08 per 1000 indwelling days, respectively. The premature catheter removal rate was 26% for PICCs and 18% for PORTs. PORTs required more additional hospital visits. Conclusions: PICCs were utilized more frequently than PORTs and had a higher rate of premature removal. The rates of VTE and CRT were similar for both CVAD types. PORTs had a lower rate of infection per 1000 indwelling days. However, the management of PORT related complications required more visits to the hospital and oncology clinic. 相似文献
9.
10.
《The Journal of thoracic and cardiovascular surgery》2023,165(2):449-459.e4
ObjectiveThe objective of this study was to investigate the association between morphological variation and postsurgical pulmonary vein (PV) stenosis (PPVS) in patients with cardiac total anomalous pulmonary venous connection (TAPVC).MethodsThis single-center, retrospective study included 168 pediatric patients who underwent surgical repair of cardiac TAPVC from 2013 to 2019 (connection to the coronary sinus [CS], n = 136; connection directly to the right atrium [RA], n = 32). Three-dimensional computed tomography modeling and geometric analysis were performed to investigate the morphological features; their relevance to the PPVS was examined.ResultsThe connection type had no association with PPVS (CS type: 18% vs right atrial type: 19%; P = .89) but there was a higher incidence of PPVS in patients with a single PV orifice than > 1 orifice (P < .001). Confluence-to-total PV area ratio (hazard ratio, 4.78, 95% CI, 1.86-12.32; P = .001) and length of drainage route (hazard ratio, 1.22; 95% CI, 1.14-1.31; P < .001) had a 4- and 1-fold increase in the risk for PPVS in the CS type after adjustment for age and preoperative pulmonary venous obstruction. In the right atrial type, those with anomalous PV return to the RA roof were more likely to develop PPVS than to the posterior wall of the RA (P < .001).ConclusionsThe number of inter-junction PV orifice correlated with PPVS development in cardiac TAPVC. The confluence-to-total PV ratio, length of drainage route, and anomalous PV return to the RA roof are important predictors for PPVS. Morphological subcategorization in this clinical setting can potentially assist in surgical decision-making. 相似文献