全文获取类型
收费全文 | 184981篇 |
免费 | 17520篇 |
国内免费 | 6231篇 |
专业分类
耳鼻咽喉 | 1121篇 |
儿科学 | 3268篇 |
妇产科学 | 2108篇 |
基础医学 | 34395篇 |
口腔科学 | 3924篇 |
临床医学 | 13159篇 |
内科学 | 33808篇 |
皮肤病学 | 3484篇 |
神经病学 | 15963篇 |
特种医学 | 4422篇 |
外国民族医学 | 35篇 |
外科学 | 14908篇 |
综合类 | 20682篇 |
现状与发展 | 27篇 |
预防医学 | 8968篇 |
眼科学 | 2290篇 |
药学 | 25635篇 |
49篇 | |
中国医学 | 6322篇 |
肿瘤学 | 14164篇 |
出版年
2023年 | 2666篇 |
2022年 | 3594篇 |
2021年 | 6609篇 |
2020年 | 6286篇 |
2019年 | 7327篇 |
2018年 | 7112篇 |
2017年 | 6820篇 |
2016年 | 6452篇 |
2015年 | 7312篇 |
2014年 | 10817篇 |
2013年 | 12202篇 |
2012年 | 10093篇 |
2011年 | 11754篇 |
2010年 | 9277篇 |
2009年 | 9325篇 |
2008年 | 9167篇 |
2007年 | 8672篇 |
2006年 | 7570篇 |
2005年 | 6967篇 |
2004年 | 6066篇 |
2003年 | 5454篇 |
2002年 | 4293篇 |
2001年 | 3776篇 |
2000年 | 3322篇 |
1999年 | 2788篇 |
1998年 | 2354篇 |
1997年 | 2461篇 |
1996年 | 2084篇 |
1995年 | 2416篇 |
1994年 | 2203篇 |
1993年 | 1906篇 |
1992年 | 1653篇 |
1991年 | 1496篇 |
1990年 | 1256篇 |
1989年 | 1027篇 |
1988年 | 987篇 |
1987年 | 893篇 |
1986年 | 931篇 |
1985年 | 1717篇 |
1984年 | 1674篇 |
1983年 | 1249篇 |
1982年 | 1198篇 |
1981年 | 1014篇 |
1980年 | 894篇 |
1979年 | 778篇 |
1978年 | 596篇 |
1977年 | 449篇 |
1976年 | 467篇 |
1975年 | 384篇 |
1974年 | 316篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
目的 探讨不同时期慢性阻塞性肺疾病(COPD)患者血清诱饵受体3(DcR3)、凋亡抑制蛋白(Survivin)表达水平及临床意义。方法 选取2018年9月—2019年12月本院收治的92名COPD患者为研究对象,其中稳定型COPD 50例,急性加重期COPD 42例;同期本院健康体检者88例为对照组。测定各组研究对象血清DcR3、Survivin水平及肺功能指标。 与对照组[DcR3(106.54±48.35)pg/mL,Survivin(98.85±26.59)pg/mL]比较,稳定期组和急性加重期组血清DcR3[(395.23±123.85)pg/mL,(1 248.81±213.59)pg/mL]、Survivin [(267.54±84.69)pg/mL,(1 233.95±307.26)pg/mL]水平升高;与稳定期组比较,急性加重期组血清DcR3、Survivin水平升高。与对照组比较,稳定期组和急性加重期组FEV1%、FEV1 /FVC、DLCO%水平降低(P<0.001);与稳定期组比较,急性加重期组FEV1%、FEV1 /FVC、DLCO%水平降低(P<0.001)。随着低氧血症严重程度的增加,COPD患者血清DcR3、Survivin水平逐渐增加(P<0.001)。多因素logistics回归分析显示,高水平DcR3、Survivin、IL-12、hs-CRP为COPD病情的危险因素(P<0.001)。DcR3、Survivin与FEV、FEV1 /FVC呈负相关,与IL-12、TNF-α、hs-CRP呈正相关(P<0.001)。 COPD稳定期、急性加重期患者血清DcR3、Survivin表达水平升高,且DcR3、Survivin与COPD病情严重程度呈正相关。 相似文献
2.
3.
4.
5.
胃癌作为临床最常见的肿瘤之一,常因确诊疾病较晚而影响治疗效果,胃镜活检后的病理虽然作为确诊的金标准,但是由于此方式过程痛苦,操作复杂,费用较高,且具有侵入性,可能会导致患者拒绝操作而难普及于临床,因此积极找寻胃癌有效的监测指标十分必要。近年来,很多学者研究维生素与胃癌的相关关系,并试图通过摄取某些维生素降低胃癌发生率,延缓病情及改善预后,也有通过检测血清中维生素的水平给早期胃癌的诊断提供帮助。本文就同型半胱氨酸、维生素D、维生素C、维生素E、维生素B12及叶酸在胃癌中的作用机制,及其在血清中水平与胃癌关系的相关研究进展进行简要综述,为临床胃癌诊疗提供新思路。 相似文献
6.
7.
8.
《Medical Journal Armed Forces India》2022,78(3):283-290
BackgroundOverordering of blood has been a challenge faced by the blood bank staff. The present study addresses the role of maximum surgical blood ordering schedule (MSBOS) in optimizing the blood inventory management.MethodsThe blood requests for elective surgical procedures from various surgical departments were reviewed to constitute MSBOS. Transfusion profile was assessed using crossmatch to transfused units (C/T) ratio, transfusion probability (TP), and transfusion index (TI). A cutoff of 0.3 and 5% value of TI and TP, respectively, was considered to decide on the type of crossmatch. The efficacy of MSBOS implementation has been determined prospectively by unpaired t test using SPSS software, version 20 (IBM, USA).ResultsA total of 2674 patients were studied. Overall red cell usage rate was 15%. The comprehensive C/T ratio was 4.57. The C/T ratios for the various departments ranged from 1 to 8.5 (adjusted C/T ratio). Highest C/T ratio was observed for surgical procedures performed in the specialties of otorhinolaryngology and urology. A C/T ratio greater than 5 was noted in 30.4% of different types of surgical procedures. Of the 176 different types of elective surgical procedures studied, type and screen protocol was applicable for 75.5% (133) of the procedures. After implementation of MSBOS, the number of crossmatches reduced by 2152 and total working time saved in our laboratory is close to 75,320 man hours.ConclusionMSBOS helps in identifying the common surgical procedures with low TP and is one of the efficient tools in preventing the overordering of the blood. 相似文献
9.
10.
《Journal of vascular and interventional radiology : JVIR》2022,33(4):384-391.e7
PurposeTo evaluate the feasibility and accuracy of a radiation-free implantation of a thoracic aortic stent graft employing fiberoptic and electromagnetic tracking in an anthropomorphic phantom.Materials and MethodsAn anthropomorphic phantom was manufactured based on computed tomography (CT) angiography data from a patient. An aortic stent graft application system was equipped with a fiber Bragg gratings and 3 electromagnetic sensors. The stent graft was navigated in the phantom by 3 interventionalists using the tracking data generated by both technologies. One implantation procedure was performed. The technical success of the procedure was evaluated using digital subtraction angiography and CT angiography (before and after the intervention). Tracking accuracy was determined at various anatomical landmarks based on separately acquired fluoroscopic images. The mean/maximum errors were measured for the stent graft application system and the tip/end of the stent graft.ResultsThe procedure resulted in technical success with a mean error below 3 mm for the entire application system and <2 mm for the position of the tip of the stent graft. Navigation/implantation and handling of the device were rated sufficiently accurate and on par with comparable, routinely used stent graft application systems.ConclusionsThe study demonstrates successful stent graft implantation during a thoracic endovascular aortic repair procedure employing advanced guidance techniques and avoiding fluoroscopic imaging. This is an essential step in facilitating the implantation of stent grafts and reducing the health risks associated with ionizing radiation during endovascular procedures. 相似文献