全文获取类型
收费全文 | 298256篇 |
免费 | 21236篇 |
国内免费 | 7142篇 |
专业分类
耳鼻咽喉 | 2257篇 |
儿科学 | 6236篇 |
妇产科学 | 4393篇 |
基础医学 | 30610篇 |
口腔科学 | 4271篇 |
临床医学 | 28473篇 |
内科学 | 56582篇 |
皮肤病学 | 2755篇 |
神经病学 | 14862篇 |
特种医学 | 9235篇 |
外国民族医学 | 2篇 |
外科学 | 26888篇 |
综合类 | 45932篇 |
一般理论 | 13篇 |
预防医学 | 20805篇 |
眼科学 | 2431篇 |
药学 | 36879篇 |
176篇 | |
中国医学 | 20419篇 |
肿瘤学 | 13415篇 |
出版年
2023年 | 4033篇 |
2022年 | 6007篇 |
2021年 | 10931篇 |
2020年 | 10949篇 |
2019年 | 9875篇 |
2018年 | 9637篇 |
2017年 | 10579篇 |
2016年 | 10408篇 |
2015年 | 10005篇 |
2014年 | 16323篇 |
2013年 | 20234篇 |
2012年 | 16426篇 |
2011年 | 19179篇 |
2010年 | 13431篇 |
2009年 | 13077篇 |
2008年 | 14289篇 |
2007年 | 15401篇 |
2006年 | 14238篇 |
2005年 | 13011篇 |
2004年 | 10834篇 |
2003年 | 9581篇 |
2002年 | 7657篇 |
2001年 | 6996篇 |
2000年 | 5790篇 |
1999年 | 5068篇 |
1998年 | 3867篇 |
1997年 | 3845篇 |
1996年 | 3436篇 |
1995年 | 3267篇 |
1994年 | 3197篇 |
1993年 | 2572篇 |
1992年 | 2380篇 |
1991年 | 2243篇 |
1990年 | 1920篇 |
1989年 | 1646篇 |
1988年 | 1540篇 |
1987年 | 1365篇 |
1986年 | 1244篇 |
1985年 | 1674篇 |
1984年 | 1394篇 |
1983年 | 990篇 |
1982年 | 1052篇 |
1981年 | 875篇 |
1980年 | 844篇 |
1979年 | 679篇 |
1978年 | 467篇 |
1977年 | 405篇 |
1976年 | 377篇 |
1975年 | 264篇 |
1974年 | 211篇 |
排序方式: 共有10000条查询结果,搜索用时 234 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.
《Saudi Pharmaceutical Journal》2022,30(6):669-678
BackgroundIschemia reperfusion (I/R) play an imperative role in the expansion of cardiovascular disease. Sinomenine (SM) has been exhibited to possess antioxidant, anticancer, anti-inflammatory, antiviral and anticarcinogenic properties. The aim of the study was scrutinized the cardioprotective effect of SM against I/R injury in rat.MethodsRat were randomly divided into normal control (NC), I/R control and I/R + SM (5, 10 and 20 mg/kg), respectively. Ventricular arrhythmias, body weight and heart weight were estimated. Antioxidant, inflammatory cytokines, inflammatory mediators and plasmin system indicator were accessed.ResultsPre-treated SM group rats exhibited the reduction in the duration and incidence of ventricular fibrillation, ventricular ectopic beat (VEB) and ventricular tachycardia along with suppression of arrhythmia score during the ischemia (30 and 120 min). SM treated rats significantly (P < 0.001) altered the level of antioxidant parameters. SM treatment significantly (P < 0.001) repressed the level of creatine kinase MB (CK-MB), creatine kinase (CK) and troponin I (Tnl). SM treated rats significantly (P < 0.001) repressed the tissue factor (TF), thromboxane B2 (TXB2), plasminogen activator inhibitor 1 (PAI-1) and plasma fibrinogen (Fbg) and inflammatory cytokines and inflammatory mediators.ConclusionOur result clearly indicated that SM plays anti-arrhythmia effect in I/R injury in the rats via alteration of oxidative stress and inflammatory reaction. 相似文献
4.
《Journal of neonatal nursing : JNN》2022,28(3):148-154
The discussion paper will focus on continuity of care relating to previous NZ research, specifically to transitioning complex preterm infants from NICU to home based on parent experiences, and on the practice developments that have occurred, to ensure optimal health outcomes. Previous NZ research discovered parent desire a consistent service delivery for the entire transition journey from NICU and at home.An informative and comprehensive opportunity has occurred for reflective professional practice, evaluation, development and implementation which have transpired in positive change through innovative practice developments and support change implementation in Wellington, NZ. This has resulted in the articulation of a model of care that has both embraced and integrated parental desires for a continuity of care process for complex preterm infants. This has been achieved by having the same Discharge Facilitator/Key Case Manager present within the NICU and external to the NICU for Home-based infants for the entire transition journey.The paper will focus and emphasis additional practice development changes and furthermore, will present a real purpose, for other countries to learn of such practice developments that have exemplified a celebratory success for families of Wellington, NZ. 相似文献
5.
6.
Anna Maria Spera 《World Journal of Virology》2022,11(5):275-282
With a 5.3% of the global population involved, hepatitis B virus (HBV) is a major public health challenge requiring an urgent response. After a possible acute phase, the natural history of HBV infection can progress in chronicity. Patients with overt or occult HBV infection can undergo HBV reactivation (HBVr) in course of immunosuppressive treatments that, apart from oncological and hem-atological diseases, are also used in rheumatologic, gastrointestinal, neurological and dermatological settings, as well as to treat severe acute respiratory syndrome coronavirus 2 infection. The risk of HBV reactivation is related to the immune status of the patient and the baseline HBV infection condition. The aim of the present paper is to investigate the risk of HBVr in those not oncological settings in order to suggest strategies for preventing and treating this occurrence. The main studies about HBVr for patients with occult hepatitis B infection and chronic HBV infection affected by non-oncologic diseases eligible for immunosuppressive treatment have been analyzed. The occurrence of this challenging event can be reduced screening the population eligible for immunosuppressant to assess the best strategies according to any virological status. Further prospective studies are needed to increase data on the risk of HBVr related to newer immunomodulant agents employed in non-oncological setting. 相似文献
7.
8.
《Transfusion and apheresis science》2022,61(2):103405
Transfusion-associated graft-versus-host disease (TA-GVHD) is a rare life-threatening complication of blood transfusion caused by donor T cells that escape rejection by the recipient immune system. These donor T cells drive recipient tissue damage in response to host antigens. On the other hand, GVHD occurring after allogeneic hematopoietic cell transplantation (HCT-GVHD) is also caused by donor T cells, but its pathophysiology is more complex and differs due to the effects of tissue damage caused by pre?HCT conditioning and profound immunosuppression. Both TA-GVHD and HCT-GVHD can be fatal; however, mortality is higher with TA-GVHD due to the paucity of treatment options. Here, we compare and summarize the presentation, diagnosis, pathophysiology, prevention, and treatment of TA-GVHD and HCT-GVHD. 相似文献
9.
10.
《Journal of Cardiovascular Computed Tomography》2022,16(6):517-523
BackgroundSelection of the transcatheter heart valve size for a mitral valve-in-valve procedure is based on the type and manufacturer’s labelled size. However, accurate information of surgical heart valve (SHV) size may not be available in the patient’s medical record. The purpose of this study is to establish reference data for computed tomography (CT) dimensions of commonly used mitral SHV in order to determine the manufacturer’s labelled size from a cardiac CT data set.MethodsCT datasets of 105 patients with surgical mitral bioprosthesis and available manufacturer labeled datasets were included in the analysis. CT derived valve dimensions were assessed by two observers using multiplanar reformats aligned with the basal sewing ring. A circular region of interest was used in a standardized fashion to minimize influence of image acquisition and reconstruction parameters. Interobserver variability was assessed by Bland-Altman analysis.ResultsThe CT-derived dimensions were stratified by valve size and type, and SHV properties were demonstrated for 5 common valve types. Variability of measurements was small and inter-observer limits of agreement were narrow. Stratified by SHV type, no overlap was noted for CT-derived dimensions among different SHV sizes . A reference table of CT characteristics of surgical mitral bioprosthesis types was created.ConclusionThe study provides reference CT data for determining the manufacturers’ labeled SHV size across a range of commonly used mitral SHVs. The findings will be important to help identify types of surgical mitral bioprosthesis utilizing CT characteristics for patients without SHV size documentation. 相似文献