全文获取类型
收费全文 | 343107篇 |
免费 | 27566篇 |
国内免费 | 10033篇 |
专业分类
耳鼻咽喉 | 2881篇 |
儿科学 | 4736篇 |
妇产科学 | 4966篇 |
基础医学 | 50208篇 |
口腔科学 | 6153篇 |
临床医学 | 24768篇 |
内科学 | 51344篇 |
皮肤病学 | 4580篇 |
神经病学 | 24865篇 |
特种医学 | 10123篇 |
外国民族医学 | 53篇 |
外科学 | 25984篇 |
综合类 | 47194篇 |
一般理论 | 14篇 |
预防医学 | 21738篇 |
眼科学 | 3927篇 |
药学 | 50776篇 |
91篇 | |
中国医学 | 19246篇 |
肿瘤学 | 27059篇 |
出版年
2024年 | 233篇 |
2023年 | 5400篇 |
2022年 | 7274篇 |
2021年 | 13901篇 |
2020年 | 12854篇 |
2019年 | 11462篇 |
2018年 | 11175篇 |
2017年 | 12092篇 |
2016年 | 11830篇 |
2015年 | 12272篇 |
2014年 | 17204篇 |
2013年 | 22243篇 |
2012年 | 18957篇 |
2011年 | 22450篇 |
2010年 | 16558篇 |
2009年 | 16940篇 |
2008年 | 17995篇 |
2007年 | 18112篇 |
2006年 | 16632篇 |
2005年 | 14987篇 |
2004年 | 12655篇 |
2003年 | 11298篇 |
2002年 | 8892篇 |
2001年 | 7737篇 |
2000年 | 6476篇 |
1999年 | 5508篇 |
1998年 | 4308篇 |
1997年 | 4285篇 |
1996年 | 3891篇 |
1995年 | 3772篇 |
1994年 | 3542篇 |
1993年 | 2945篇 |
1992年 | 2610篇 |
1991年 | 2463篇 |
1990年 | 2083篇 |
1989年 | 1720篇 |
1988年 | 1636篇 |
1987年 | 1418篇 |
1986年 | 1309篇 |
1985年 | 1987篇 |
1984年 | 1707篇 |
1983年 | 1238篇 |
1982年 | 1286篇 |
1981年 | 1067篇 |
1980年 | 959篇 |
1979年 | 765篇 |
1978年 | 500篇 |
1977年 | 422篇 |
1976年 | 403篇 |
1975年 | 284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.
《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
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.
《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
7.
8.
Species identification of unknown biological samples is crucial for forensic applications, especially in cases of explosion, disaster accidents, and body mutilation after murdering, as well as poaching, illegal trade in endangered animals, and meat food fraud. In this study, we identified 60 volatile organic compounds (VOCs) in fresh skeletal muscle tissues of seven different animal species (cattle, sheep, pigs, rabbits, rats, chickens and carp) and a human dead body by headspace-gas-chromatography ion-mobility spectrometry (HS-GC-IMS), and compared their differences by retention time, drift time and molecular weight. The results showed that these VOCs formed different gallery plot fingerprints in the skeletal muscle tissues of the human dead body and seven animal species. Principal component analysis (PCA) showed significantly different fingerprints between these species, and these fingerprints maintained good stability between the species and within the same species. Some VOCs have high species specificity, while VOCs of human fresh muscle tissues from different individual sources have little difference, demonstrating that all tested muscle tissue samples could be distinguished based on different VOCs. HS-GC-IMS has proved to be a rapid, high-throughput, highly sensitive and specific species identification method, which can be used for forensic species identification in criminal cases and disaster accidents, as well as detection in the field of food safety, such as meat fraud and adulteration. 相似文献
9.
Nanotherapy: New Approach for Impeding Hepatic Cancer Microenvironment via Targeting Multiple Molecular Pathways 下载免费PDF全文
Ahmed A Abd-Rabou Hanaa H Ahmed Safaa H MohamedSoheir E KotobMohamed S Kishta 《Asian Pacific journal of cancer prevention》2022,23(12):4261-4273
Objective: Hepatocellular carcinoma (HCC) microenvironment has been recognized as a key contributor for cancer progression, metastasis, and drug resistance. The crosstalk between tumor cells, the vascular endothelial growth factor (VEGF), and the chemokine (C-C motif) ligand 2 (CCL2) signaling networks mediates immunoinhibitory impact and facilitates tumor angiogenesis. The current investigation aimed at exploring the potent anti-cancer activity of the newly designed nano-based anti-cancer therapy comprising anti-VEGF drug, avastin (AV), and CCR2 antagonist (CR) to counteract HCC and tracking its mode of action in vivo. Methods: The prepared AV, CR, and AVCR nanoprototypes were characterized by nanoscale characterization techniques in our previous work. Here, they are applied for unearthing their anti-cancer properties / mechanisms in hepatic cancer-induced rats via analyzing protein levels and genetic expression of the elements incorporated in the angiogenesis, apoptosis, and metastasis signalling pathways. Results: The present results revealed a significant down-regulation in the angiogenesis, survival and metastasis indices along with up-regulation in the pro-apoptotic mediators upon treatment of hepatic cancer-bearing rats with the novel synthesized nanomaterials when compared with the untreated counterparts. We showed across HCC model that anti-VEGF in combination with CCR2 antagonism therapy leads to sensitization and enhanced tumor response over anti-VEGF or CCR2 antagonism monotherapy, particularly in its nanoscale formulation. Conclusion: The present approach provides new mechanistic insights into the powerful anti-hepatic cancer advantage of the novel nanoprototypes which is correlated with modulating critical signal transduction pathways implicated in tumor microenviroment such as angiogenesis, apoptosis and metastasis. This research work presents a substantial foundation for future studies focused on prohibiting cancer progression and recovery by targeting tumor microenviroment. 相似文献
10.