全文获取类型
收费全文 | 113085篇 |
免费 | 11563篇 |
国内免费 | 5934篇 |
专业分类
耳鼻咽喉 | 839篇 |
儿科学 | 1114篇 |
妇产科学 | 1508篇 |
基础医学 | 29320篇 |
口腔科学 | 3393篇 |
临床医学 | 7789篇 |
内科学 | 15669篇 |
皮肤病学 | 2126篇 |
神经病学 | 8512篇 |
特种医学 | 2244篇 |
外国民族医学 | 28篇 |
外科学 | 8954篇 |
综合类 | 16544篇 |
一般理论 | 6篇 |
预防医学 | 5570篇 |
眼科学 | 2969篇 |
药学 | 11743篇 |
16篇 | |
中国医学 | 3462篇 |
肿瘤学 | 8776篇 |
出版年
2024年 | 56篇 |
2023年 | 1376篇 |
2022年 | 1828篇 |
2021年 | 3334篇 |
2020年 | 3601篇 |
2019年 | 3067篇 |
2018年 | 3049篇 |
2017年 | 3796篇 |
2016年 | 4060篇 |
2015年 | 4565篇 |
2014年 | 7011篇 |
2013年 | 8770篇 |
2012年 | 7022篇 |
2011年 | 8122篇 |
2010年 | 6573篇 |
2009年 | 6334篇 |
2008年 | 6596篇 |
2007年 | 6614篇 |
2006年 | 6058篇 |
2005年 | 5135篇 |
2004年 | 4394篇 |
2003年 | 3586篇 |
2002年 | 2766篇 |
2001年 | 2378篇 |
2000年 | 2005篇 |
1999年 | 1672篇 |
1998年 | 1414篇 |
1997年 | 1322篇 |
1996年 | 1197篇 |
1995年 | 1379篇 |
1994年 | 1244篇 |
1993年 | 1078篇 |
1992年 | 917篇 |
1991年 | 856篇 |
1990年 | 724篇 |
1989年 | 705篇 |
1988年 | 606篇 |
1987年 | 549篇 |
1986年 | 483篇 |
1985年 | 723篇 |
1984年 | 648篇 |
1983年 | 455篇 |
1982年 | 574篇 |
1981年 | 440篇 |
1980年 | 375篇 |
1979年 | 328篇 |
1978年 | 225篇 |
1977年 | 175篇 |
1976年 | 150篇 |
1975年 | 63篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
《Archivos de bronconeumología》2022,58(12):802-808
IntroductionThe main aim of this study was to assess the utility of differential white cell count and cell population data (CPD) for the detection of COVID-19 in patients admitted for community-acquired pneumonia (CAP) of different etiologies.MethodsThis was a multicenter, observational, prospective study of adults aged ≥18 years admitted to three teaching hospitals in Spain from November 2019 to November 2021 with a diagnosis of CAP. At baseline, a Sysmex XN-20 analyzer was used to obtain detailed information related to the activation status and functional activity of white cells.ResultsThe sample was split into derivation and validation cohorts of 1065 and 717 patients, respectively. In the derivation cohort, COVID-19 was confirmed in 791 patients and ruled out in 274 patients, with mean ages of 62.13 (14.37) and 65.42 (16.62) years, respectively (p < 0.001). There were significant differences in all CPD parameters except MO-Y. The multivariate prediction model showed that lower NE-X, NE-WY, LY-Z, LY-WY, MO-WX, MO-WY, and MO-Z values and neutrophil-to-lymphocyte ratio were related to COVID-19 etiology with an AUC of 0.819 (0.790, 0.846). No significant differences were found comparing this model to another including biomarkers (p = 0.18).ConclusionsAbnormalities in white blood cell morphology based on a few cell population data values as well as NLR were able to accurately identify COVID-19 etiology. Moreover, systemic inflammation biomarkers currently used were unable to improve the predictive ability. We conclude that new peripheral blood biomarkers can help determine the etiology of CAP fast and inexpensively. 相似文献
2.
3.
4.
5.
《The Journal for Nurse Practitioners》2022,18(2):164-167
Acute diarrhea is a condition of increased water stool content, stool volume, and number of bowel movements that lasts less than 14 days. Mild diarrhea is usually self-limiting; however, undertreated moderate to severe diarrhea may cause severe dehydration and lead to hypovolemic shock. In order to prevent severe dehydration and treat patients appropriately, it is crucial for health care providers to determine the right diagnosis of patients with acute diarrhea. This article focuses on pathophysiology, general patient presentation, diagnostic tests and differential diagnosis lists of acute diarrhea to discuss which diagnosis should be made based on patient presentation and objective data. 相似文献
6.
《Journal of vascular and interventional radiology : JVIR》2022,33(10):1143-1150
PurposeTo report the 5-year results from the Pivotal Multicenter Trial of Ultrasound-Guided Percutaneous Arteriovenous Fistula (pAVF) Creation for Hemodialysis Access.Materials and MethodsThe retrospective review of 107 intent-to-treat (ITT) patients from the pivotal trial provided a long-term follow-up population (LTP) of 85 patients with a median follow-up duration of 50 months (range, 12–60 months). Data evaluated in the LTP group were fistula maturation and usage, secondary procedures, and complications. The Kaplan-Meier analysis of primary patency, assisted primary patency, cumulative patency, and functional patency (time from 2-needle cannulation to abandonment) were performed for the ITT population.ResultsIn the LTP, 99% (84 of 85) of fistulae were mature, with 99% (78 of 79) of patients requiring hemodialysis using their pAVF. Sustained fistula use (2-needle cannulation at the prescribed rate, 2 of 3 sessions) was achieved in 92% (78 of 85) of patients, with 7 patients not using their pAVF because they were not on dialysis (n = 4), were on peritoneal dialysis (n = 2), and refused to use fistula (n = 1). Fistula maintenance was required in 31.8% (27 of 85) of patients and included fistula dysfunction (21.2%), thrombosis (5.9%), cannulation injury (12.9%), and arm swelling (4.7%). The number of procedures performed per patient per year to maintain function and patency was 0.32 (91 of 288) for years 2–5. The cumulative patency rates were 89.5%, 88.4%, 88.4%, 85.6%, and 82.0% for years 1, 2, 3, 4, and 5, respectively. The functional patency was 91.8% at the end of the study. There were no major complications related to pAVF during the long-term follow-up.ConclusionsPercutaneous fistulae have provided clinically effective and durable access for hemodialysis with low complications. The continued use and evaluation of pAVF are warranted. 相似文献
7.
8.
目的探讨放疗干预对宫颈癌荷瘤小鼠的抑瘤作用及其对辅助性T细胞1(Th1)/Th2细胞比例的影响。方法建立宫颈癌荷瘤小鼠模型,随机分为荷瘤组和放疗组,每组各10只,另设对照组10只。放疗组进行放疗干预14天,荷瘤组和对照组不治疗。放疗后4、6、8、10、12、14天测量肿瘤体积;末次治疗后,ELISA法测定血清干扰素-γ(IFN-γ)、白介素-2(IL-2)、IL-4、IL-10含量;计算抑瘤率、胸腺指数和脾脏指数;HE染色观察肿瘤组织学变化;TUNEL染色观察肿瘤组织细胞凋亡情况;流式细胞术检测脾脏Th1/Th2细胞比例;RT-qPCR和Western blot检测脾脏T盒子转录因子(T-bet)、GATA结合蛋白3(GABA-3)mRNA和蛋白表达。结果与荷瘤组比较,放疗组小鼠4、6、8、10、12、14天肿瘤体积及瘤质量减小,血清IL-2、IFN-γ升高,IL-4、IL-10降低,胸腺指数、脾脏指数升高,Th1细胞比例、Th1/Th2增加,Th2细胞比例减少,T-bet mRNA和蛋白及T-bet/GATA-3表达升高,GATA-3 mRNA和蛋白表达降低(P<0.05)。HE染色显示,荷瘤组肿瘤细胞数量较多,核大深染,无明显坏死;放疗组肿瘤细胞数量减少,出现大量坏死组织。TUNEL染色显示,荷瘤组TUNEL阳性细胞较少,放疗组TUNEL阳性细胞明显增多。结论放疗对宫颈癌荷瘤小鼠具有明显抑瘤作用,可能是通过调节T-bet/GATA-3表达,促进Th1/Th2分化平衡,增强机体免疫功能发挥作用。 相似文献
9.
XI Hui CHENG Guan Liang HU Fei Fei LI Song Nan DENG Xuan ZHOU Yong 《Biomedical and environmental sciences : BES》2022,35(3):206-214
Objective To explore associations between lipoprotein-associated phospholipase A2(Lp-PLA2) and the risk of cardiovascular events in a Chinese population, with a long-term follow-up.Methods A random sample of 2,031 participants(73.6% males, mean age = 60.4 years) was derived from the Asymptomatic Polyvascular Abnormalities Community study(APAC) from 2010 to 2011. Serum Lp-PLA2 levels were determined by enzyme-linked immunosorbent assay(ELISA). The composite endpoint was a combination of first-eve... 相似文献
10.
目的分析肝移植术后受者外周血CD19+CD24hiCD38hi B细胞占单个核细胞比例变化情况及其与急性细胞性排斥反应(ACR)之间的关系。 方法回顾性分析2013年12月至2015年12月在浙江大学医学院附属第一医院接受心脏死亡器官捐献肝移植的80例成人受者临床资料,根据术后是否发生ACR,将受者分为ACR组(25例)和非ACR组(55例)。术前、术后各个时间点抽取参加研究者静脉血并分离外周血单个核细胞,加入异硫氰酸荧光素-单克隆鼠抗人CD19抗体、藻红蛋白-单克隆鼠抗人CD24抗体和别藻蓝蛋白-单克隆鼠抗人CD38抗体,流式细胞仪检测各组CD19+CD24hiCD38hi B细胞百分比。采用t检验和单因素方差分析比较正态分布计量资料,采用χ2检验比较计数资料,采用Kaplan-Meier法绘制受试者工作特征曲线(ROC曲线)。P<0.05为差异有统计学意义。 结果ACR组、非ACR组受者术前外周血平均CD19+CD24hiCD38hi B细胞比例分别为(3.13±0.91)%、(3.49±0.83)%,差异无统计学意义(t=1.636,P>0.05)。ACR组术后发生ACR前外周血平均CD19+CD24hiCD38hi B细胞比例为(1.87±0.70)%。非ACR组受者术后3个月、6个月和1年外周血平均CD19+CD24hiCD38hi B细胞比例分别为(1.64±0.52)%、(1.63±0.56)%和(2.04±1.24)%,术后3、6个月平均值均低于术前和术后1年,差异均有统计学意义(P均<0.05)。ACR组受者发生ACR时外周血平均CD19+CD24hiCD38hi B细胞比例为(0.8±0.5)%,低于发生ACR前的平均水平(t=5.752,P<0.05),且低于非ACR组术后3个月、6个月和1年的平均水平(P<0.05)。ACR组受者接受抗排斥反应治疗后,CD19+CD24hiCD38hi B细胞比例也逐渐增加,ACR发生后7 d为(0.84±0.08)%,与ACR发生时相比差异无统计学意义(P>0.05);而发生30 d后达(1.65±0.18)%,与ACR发生时相比差异有统计学意义(P<0.05)。当截断值为1.015%时,CD19+CD24hiCD38hi B细胞比例预测ACR发生的敏感度和特异度分别为0.786和0.702,ROC曲线下面积为0.775(95%CI: 0.671~0.879,P<0.05)。 结论CD19+CD24hiCD38hi B细胞比例下降与肝移植术后ACR反应发生有关,并可作为预测ACR发生的细胞标志物。 相似文献