全文获取类型
收费全文 | 256625篇 |
免费 | 29123篇 |
国内免费 | 15662篇 |
专业分类
耳鼻咽喉 | 2890篇 |
儿科学 | 3256篇 |
妇产科学 | 3327篇 |
基础医学 | 19590篇 |
口腔科学 | 6206篇 |
临床医学 | 32168篇 |
内科学 | 32531篇 |
皮肤病学 | 2481篇 |
神经病学 | 11184篇 |
特种医学 | 15973篇 |
外国民族医学 | 44篇 |
外科学 | 24841篇 |
综合类 | 46056篇 |
现状与发展 | 82篇 |
一般理论 | 8篇 |
预防医学 | 28879篇 |
眼科学 | 5905篇 |
药学 | 25580篇 |
610篇 | |
中国医学 | 26702篇 |
肿瘤学 | 13097篇 |
出版年
2024年 | 896篇 |
2023年 | 5413篇 |
2022年 | 11333篇 |
2021年 | 13467篇 |
2020年 | 12690篇 |
2019年 | 7542篇 |
2018年 | 7984篇 |
2017年 | 6845篇 |
2016年 | 7981篇 |
2015年 | 9223篇 |
2014年 | 20092篇 |
2013年 | 18310篇 |
2012年 | 25093篇 |
2011年 | 24884篇 |
2010年 | 18694篇 |
2009年 | 13773篇 |
2008年 | 11651篇 |
2007年 | 13970篇 |
2006年 | 11863篇 |
2005年 | 8308篇 |
2004年 | 7602篇 |
2003年 | 7099篇 |
2002年 | 5818篇 |
2001年 | 5174篇 |
2000年 | 4343篇 |
1999年 | 4150篇 |
1998年 | 3204篇 |
1997年 | 2871篇 |
1996年 | 1839篇 |
1995年 | 1176篇 |
1994年 | 868篇 |
1993年 | 719篇 |
1992年 | 1421篇 |
1991年 | 1196篇 |
1990年 | 1114篇 |
1989年 | 529篇 |
1988年 | 571篇 |
1987年 | 451篇 |
1986年 | 380篇 |
1985年 | 159篇 |
1984年 | 191篇 |
1983年 | 108篇 |
1982年 | 104篇 |
1981年 | 120篇 |
1980年 | 68篇 |
1979年 | 17篇 |
1978年 | 43篇 |
1977年 | 29篇 |
1976年 | 34篇 |
排序方式: 共有10000条查询结果,搜索用时 46 毫秒
51.
52.
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
53.
目的 评价调整光学切削直径及Kappa角后对准分子激光原位角膜磨镶术(laser in situ keratomileusis,LASIK)后效果的影响。方法 选取2017年1月至12月在我院行LASIK手术的高度近视患者313例(626眼),根据切削直径分成两组,试验组157例314眼,切削直径设定为6.0 mm,对照组156例312眼,切削直径设定为6.5 mm。试验组患者激光切削前修正Kappa角,对照组不做修正。患者术前进行裸眼视力、主视眼确定、验光、眼压、暗室下瞳孔直径、泪液分泌试验、裂隙灯、散瞳验光、眼底检查、pentacam测量角膜厚度、角膜地形图测量角膜前后表面及Kappa角等检查。术后1 d、1周、1个月随访,并检查裸眼视力、角膜厚度、波前像差及夜间视力、光晕、眩光等情况。比较两组患者角膜厚度变化、手术所用时间以及两组患者术后的高阶像差的差异。结果 试验组与对照组患者年龄分别为18~44(24.19±5.33)岁、18~42(25.08±4.91)岁,屈光度分别为(-7.47±1.04)D、(-7.61±1.12)D。两组年龄、屈光度比较差异均无统计学意义(均为P>0.05)。试验组与对照组患者术前Kappa角分别为,X轴:(210±40)μm、(200±30)μm,Y轴:(190±30)μm、(220±40)μm,差异无统计学意义(P=0.210)。两组手术前后的角膜厚度及术后角膜基质床的厚度差异均无统计学意义(均为P>0.05)。试验组与对照组的手术时间分别为(15.56±1.89)s和(20.83±3.03)s,差异有统计学意义(P=0.000)。试验组的总高阶像差和垂直慧差的变化均明显低于对照组(均为 P<0.01),但两组间的水平慧差差异无统计学意义(P>0.05),对照组的球差低于试验组(P<0.01)。结论 LASIK手术中科学合理地调整Kappa角可有助于提高患者术后的视觉质量。 相似文献
54.
目的 对学龄期近视进展儿童进行调节功能的客观检查与分析,观察调节功能与近视进展之间的相关性。方法 选取2017年至2018年在首都医科大学附属北京同仁医院视光学门诊定期就诊的71名学龄期儿童为研究对象,根据受试者近年的屈光度进展速度,按≤0.50 D·a-1、>0.50~1.00 D·a-1、>1.00~1.50 D·a-1、>1.50 D·a-1分为4组,使用人眼调节分析仪对受试者进行调节功能的客观测量与分析,记录不同调节刺激视标下4组的客观调节反应值和客观调节微波动值,并作对比。结果 在所有调节视标上,各组随着调节刺激幅度增加,客观调节反应值也逐渐增加,4组在不同调节刺激视标下的客观调节反应值及平均的客观调节反应值差异均无统计学意义(均为P>0.05)。≤0.50 D·a-1、>0.50~1.00 D·a-1、>1.00~1.50 D·a-1、>1.50 D·a-1近视进展速度组调节微波动值分别为(62.2±5.6)D、(62.5±5.3)D、(66.5±6.0)D和(58.0±6.5)D,4组间差异有统计学意义(F=6.424,P=0.001),在+0.50~-0.50 D、-2.00 D调节刺激视标下,4组的客观调节微波动值比较差异均有统计学意义(均为P<0.05),在其余调节刺激视标下差异均无统计学意义(均为P>0.05)。结论 对于学龄期儿童的近视进展速度,客观调节微波动值相对于客观调节反应值可能是一个更为敏感的相关指标。 相似文献
55.
目的 比较1.8 mm同轴微切口超声乳化术与传统同轴3.0 mm小切口超声乳化术的临床疗效及术后并发症。方法 收集2015年5月至10月北京同仁医院北京同仁眼科中心收治的老年性白内障患者48例(48眼),将患者分为微切口组和小切口组。微切口组主切口长1.8 mm,前房内注入透明质酸钠,行直径约为5.0 mm的中央连续环形撕囊,水分离后用劈核钩劈核,扭动模式超声乳化吸出术,自动灌注系统吸出残留皮质。小切口组角膜主切口大小为3.0 mm,术中植入常规折叠式人工晶状体。术后行裂隙灯、眼底镜以及角膜地形图检查,电脑验光检查患者最佳矫正视力。结果 术后1周、1个月、3个月两组患者最佳矫正视力比较,差异均无统计学意义(均为P>0.05)。术后1个月和3个月两组间手术源性散光比较,微切口组均明显低于小切口组,差异均有统计学意义(均为P<0.01)。在微切口组组内术后1个月和3个月手术源性散光无明显差异(P>0.05),微切口组手术源性散光在术后1个月保持稳定。在小切口组组内术后3个月手术源性散光明显低于术后1个月 (P<0.01)。微切口组术前角膜厚度为(567±27)μm,小切口组为(564±25)μm,两组差异无统计学意义(P>0.05);术后1个月与3个月两组间角膜厚度变化差异亦均无统计学意义(均为P>0.05)。在随访期间两组患者均未发生后发性白内障。结论 1.8 mm同轴微切口白内障超声乳化吸出术安全可靠,术后散光恢复快,可有效减少术后角膜手术源性散光。 相似文献
56.
《Australian critical care》2019,32(6):540-559
ObjectivesThe objective of this review was to describe cardiovascular risk (CVR) assessment methods and to identify evidence-based practice recommendations when dealing with population at risk of developing cardiovascular diseases.Review methods and data sourcesA literature review following the Arksey and O'Malley scoping review methodology was conducted. By using appropriate key terms, literature searches were conducted in PubMed, SciELO, Cochrane Library, Dialnet, ENFISPO, Medigraphic, ScienceDirect, Cuiden, and Lilacs databases. A complementary search on websites related to the area of interest was conducted. Articles published in English or Spanish in peer-review journals between 2010 and 2017. Critical appraisal for methodological quality was conducted. Data was extracted using ad-hoc tables and qualitatively synthesized.ResultsAfter eliminating duplicates, 55 325 records remained, and 1432 records were selected for screening. Out of these, 88 full-text articles were selected for eligibility criteria, and finally, 67 studies were selected for this review, and 25 studies were selected for evidence synthesis. In total, 23 CVR assessment tools have been identified, pioneered by the Framingham study. Qualitative findings were grouped into four thematic areas: assessment tools and scores, CVR indicators, comparative models, and evidence-based recommendations.ConclusionsIt is necessary to adapt the instruments to the epidemiological reality of the population. The most appropriate way to estimate CVR is to choose the assessment tool that best suits individual conditions, accompanied by a comprehensive assessment of the patient. More research is required to determine a single, adequate, and reliable tool. 相似文献
57.
《Biomedical and environmental sciences : BES》2020,33(5):295-305
Objective Interferon-induced transmembrane protein 3(IFITM3) is an important member of the IFITM family. However, the molecular mechanisms underlying its antiviral action have not been completely elucidated. Recent studies on IFITM3, particularly those focused on innate antiviral defense mechanisms, have shown that IFITM3 affects the body's adaptive immune response. The aim of this study was to determine the contribution of IFITM3 proteins to immune control of influenza infection in vivo.Methods We performed proteomics, flow cytometry, and immunohistochemistry analysis and used bioinformatics tools to systematically compare and analyze the differences in natural killer(NK) cell numbers, their activation, and their immune function in the lungs of Ifitm3-/-and wild-type mice.Results Ifitm3-/-mice developed more severe inflammation and apoptotic responses compared to wild-type mice. Moreover, the NK cell activation was higher in the lungs of Ifitm3-/-mice during acute influenza infection.Conclusions Based on our results, we speculate that the NK cells are more readily activated in the absence of IFITM3, increasing mortality in Ifitm3-/-mice. 相似文献
58.
59.
60.
《The Journal of arthroplasty》2020,35(7):1885-1890
BackgroundThe aim of this study is to evaluate midterm clinical and radiographic results of total hip arthroplasties (THAs) with cementless implants for adult patients with sequelae from childhood hip infection.MethodsBetween 2002 and 2016, 165 patients (165 hips) who had a hip infection during childhood were treated with THAs with cementless implants. The average duration of follow-up was 93.5 months (range 26-206). Clinical results were evaluated via the Harris Hip Score and radiographic results were analyzed with postoperative serial X-rays.ResultsThe average Harris Hip Score increased from 27 (range 8-53) before surgery to 91 (range 45-100) at the latest follow-up examination (P < .001). At the latest follow-up evaluation, 9 cementless acetabular components demonstrated partial, nonprogressive radiolucencies. No subsidence of more than 2 mm or evidence of a radiolucent line was observed around the femoral components. Intraoperative periprosthetic fractures occurred in 11 hips, including 3 acetabular fractures, 2 fractures of greater trochanter, 1 femoral shaft fracture, and 5 fractures of femoral calcar. Postoperative complications included 3 cases of periprosthetic infection, 1 episode of dislocation, 1 case of a femoral periprosthetic fracture, 5 cases of sciatic nerve injury, 1 case of femoral nerve injury, and 1 case of squeaking from a ceramic bearing surface.ConclusionCementless THA for adult patients with sequelae from childhood hip infection presents significant technical challenges and a relatively high complication rate. With meticulous surgical planning and anticipation for the key technical challenges frequently encountered, the medium-term clinical and radiographic results of THA in this setting were good with high implant survivorship and patient satisfaction. 相似文献