全文获取类型
收费全文 | 344203篇 |
免费 | 29786篇 |
国内免费 | 12170篇 |
专业分类
耳鼻咽喉 | 3791篇 |
儿科学 | 6274篇 |
妇产科学 | 4904篇 |
基础医学 | 54166篇 |
口腔科学 | 9279篇 |
临床医学 | 25906篇 |
内科学 | 44212篇 |
皮肤病学 | 6640篇 |
神经病学 | 22318篇 |
特种医学 | 10188篇 |
外国民族医学 | 122篇 |
外科学 | 30096篇 |
综合类 | 50890篇 |
现状与发展 | 66篇 |
一般理论 | 10篇 |
预防医学 | 18563篇 |
眼科学 | 5869篇 |
药学 | 37413篇 |
83篇 | |
中国医学 | 17397篇 |
肿瘤学 | 37972篇 |
出版年
2024年 | 242篇 |
2023年 | 4439篇 |
2022年 | 5989篇 |
2021年 | 12154篇 |
2020年 | 11465篇 |
2019年 | 11243篇 |
2018年 | 11572篇 |
2017年 | 12498篇 |
2016年 | 12833篇 |
2015年 | 13399篇 |
2014年 | 17860篇 |
2013年 | 22855篇 |
2012年 | 18896篇 |
2011年 | 22078篇 |
2010年 | 16274篇 |
2009年 | 15872篇 |
2008年 | 17734篇 |
2007年 | 18792篇 |
2006年 | 17427篇 |
2005年 | 15975篇 |
2004年 | 13802篇 |
2003年 | 12095篇 |
2002年 | 9620篇 |
2001年 | 8458篇 |
2000年 | 6998篇 |
1999年 | 5955篇 |
1998年 | 4669篇 |
1997年 | 4693篇 |
1996年 | 4181篇 |
1995年 | 4083篇 |
1994年 | 3770篇 |
1993年 | 3155篇 |
1992年 | 2749篇 |
1991年 | 2567篇 |
1990年 | 2140篇 |
1989年 | 1846篇 |
1988年 | 1763篇 |
1987年 | 1509篇 |
1986年 | 1400篇 |
1985年 | 1938篇 |
1984年 | 1631篇 |
1983年 | 1199篇 |
1982年 | 1262篇 |
1981年 | 1032篇 |
1980年 | 959篇 |
1979年 | 743篇 |
1978年 | 489篇 |
1977年 | 404篇 |
1976年 | 359篇 |
1975年 | 226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.
《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.
Effect of Replacement of Wharton Acellular Jelly With FBS on the Expression of Megakaryocyte Linear Markers in Hematopoietic Stem Cells CD34+ 下载免费PDF全文
zahra Jalili Behnam Emamgolizadeh Hossein Abbaszadeh Shahla JaliliMehdi Derakhshani Mehdi YousefiMehdi TalebiKarim Shams Asenjan Ali Akabr Movassaghpour 《Asian Pacific journal of cancer prevention》2022,23(10):3281-3286
Objective: Animal environments for the growth of stem cells cause the transmission of some diseases and immune problems for the recipient. Accordingly, replacing these environments with healthy environments, at least with human resources, is essential. One of the media that can be used as an alternative to animal serums is Wharton acellular jelly (AWJ). Therefore, in this study, we intend to replace FBS with Wharton jelly and investigate its effect on the expression of megakaryocyte-related genes and markers in stem cells. Materials and Methods: In this study, cord blood-derived CD34 positive HSCs were cultured and expanded in the presence of cytokines including SCF, TPO, and FLT3-L. Then, the culture of expanded CD34 positive HSCs was performed in two groups: 1) IMDM culture medium containing 10% FBS and 100 ng / ml thrombopoietin cytokine 2) IMDM culture medium containing 10% AWJ, 100 ng / ml thrombopoietin cytokine. Finally, CD41 expressing cells were analyzed with the flow cytometry method. The genes related to megakaryocyte lineage including FLI1 and GATA2 were also evaluated using the RT-PCR technique. Results: The expression of CD41, a specific marker of megakaryocyte lineage in culture medium containing Wharton acellular jelly was increased compared to the FBS group. Additionally, the expression of GATA2 and FLI1 genes was significantly increased related to the control group. Conclusion: This study provided evidence of differentiation of CD34 positive hematopoietic stem cells from umbilical cord blood to megakaryocytes in a culture medium containing AWJ. 相似文献
7.
8.
《European journal of surgical oncology》2022,48(5):1062-1067
BackgroundSurgical resection is recommended for patients with resectable acinar cell carcinoma (ACC). The aim of this study was to investigate the clinical characteristics and surgical outcomes of resectable ACC in comparison to pancreatic ductal adenocarcinoma (PDAC).MethodA retrospective analysis was performed on all patients who consecutively underwent radical resection with pathologically confirmed ACC and PDAC from December 2011 to December 2018. Clinicopathologic characteristics and follow-up information were analyzed. A 1:3 propensity score matching (PSM) method was used to minimize the bias between ACC and PDAC.ResultsA total of 26 patients with ACC and 1351 with PDAC were included. Compared to PDAC, ACC tended to be larger (4.5 vs. 3.0 cm; p < 0.001) and more frequently located in the pancreatic body/tail (61.5% vs. 36.6%, p = 0.009), with lower total bilirubin levels, lower neutrophil lymphocyte ratio (NLR) levels and lower carbohydrate antigen 19-9 (CA19-9) levels and carcinoembryonic antigen (CEA) levels. There was no difference in postoperative morbidities in patients with ACC and PDAC. The median OS and RFS were longer in ACC when compared to PDAC (OS: 43.5 mo vs. 19.0 mo, p = 0.004; RFS: 24.5 mo vs. 11.6 mo, p = 0.023). After the 1:3 PSM, ACC remained to be a better histological type for OS (p = 0.024), but had comparable RFS with PDAC (p = 0.164).ConclusionPatients with ACC after radical resection had better OS than that with PDAC. However, ACC is also an aggressive tumor with a similar trend of RFS with PDAC after the matching, necessitating the multidisciplinary treatment for resectable ACC disease. 相似文献
9.
10.
Mahmut Gümüş MD Chieh-I Chen MPH Cristina Ivanescu PhD Saadettin Kilickap MD Igor Bondarenko MD Mustafa Özgüroğlu MD Miranda Gogishvili MD Haci M. Turk MD Irfan Cicin MD James Harnett PharmD Vera Mastey MS Ulrike Naumann MS Matthew Reaney MS Gerasimos Konidaris MS Medha Sasane PhD Keri J. S. Brady PhD Siyu Li PhD Giuseppe Gullo MD Petra Rietschel MD Ahmet Sezer MD 《Cancer》2023,129(1):118-129