全文获取类型
收费全文 | 315082篇 |
免费 | 31350篇 |
国内免费 | 10987篇 |
专业分类
耳鼻咽喉 | 2041篇 |
儿科学 | 6947篇 |
妇产科学 | 4202篇 |
基础医学 | 63497篇 |
口腔科学 | 6581篇 |
临床医学 | 20528篇 |
内科学 | 51556篇 |
皮肤病学 | 5968篇 |
神经病学 | 25582篇 |
特种医学 | 7705篇 |
外国民族医学 | 90篇 |
外科学 | 23874篇 |
综合类 | 38077篇 |
现状与发展 | 52篇 |
预防医学 | 14449篇 |
眼科学 | 3505篇 |
药学 | 40592篇 |
61篇 | |
中国医学 | 11121篇 |
肿瘤学 | 30991篇 |
出版年
2023年 | 4646篇 |
2022年 | 6150篇 |
2021年 | 12040篇 |
2020年 | 11209篇 |
2019年 | 12794篇 |
2018年 | 12301篇 |
2017年 | 11977篇 |
2016年 | 11517篇 |
2015年 | 13409篇 |
2014年 | 19133篇 |
2013年 | 21274篇 |
2012年 | 18744篇 |
2011年 | 22202篇 |
2010年 | 18545篇 |
2009年 | 17957篇 |
2008年 | 17288篇 |
2007年 | 15620篇 |
2006年 | 13994篇 |
2005年 | 12112篇 |
2004年 | 10650篇 |
2003年 | 9153篇 |
2002年 | 7104篇 |
2001年 | 6201篇 |
2000年 | 5092篇 |
1999年 | 4486篇 |
1998年 | 3564篇 |
1997年 | 3472篇 |
1996年 | 2895篇 |
1995年 | 3107篇 |
1994年 | 2812篇 |
1993年 | 2438篇 |
1992年 | 1935篇 |
1991年 | 1687篇 |
1990年 | 1481篇 |
1989年 | 1203篇 |
1988年 | 1079篇 |
1987年 | 930篇 |
1986年 | 996篇 |
1985年 | 1868篇 |
1984年 | 2016篇 |
1983年 | 1447篇 |
1982年 | 1606篇 |
1981年 | 1328篇 |
1980年 | 1128篇 |
1979年 | 998篇 |
1978年 | 777篇 |
1977年 | 620篇 |
1976年 | 695篇 |
1975年 | 490篇 |
1974年 | 410篇 |
排序方式: 共有10000条查询结果,搜索用时 171 毫秒
91.
92.
《Drug discovery today》2022,27(1):223-233
Approaches based on animal and two-dimensional (2D) cell culture models cannot ensure reliable results in modeling novel pathogens or in drug testing in the short term; therefore, there is rising interest in platforms such as organoids. To develop a toolbox that can be used successfully to overcome current issues in modeling various infections, it is essential to provide a framework of recent achievements in applying organoids. Organoids have been used to study viruses, bacteria, and protists that cause, for example, respiratory, gastrointestinal, and liver diseases. Their future as models of infection will be associated with improvements in system complexity, including abilities to model tissue structure, a dynamic microenvironment, and coinfection.Teaser.Organoids are a flexible tool for modelling viral, bacterial and protist infections. They can provide fast and reliable information on the biology of pathogens and in drug screening, and thus have become essential in combatting emerging infectious diseases. 相似文献
93.
Ochratoxin A (OTA) is a mycotoxin that mainly causes nephrotoxicity. The single nephrotoxicity of OTA exposure on glomeruli or renal tubule had been well documented, however, the comparison toxicity between it is still unclear. Here, C57BL/6 mice and two types of nephrocyte were treated with concentration-gradient OTA to explore its differentiation nephrotoxicity. Results showed that OTA induced nephrotoxicity in vivo and in vitro, manifested as the deteriorative kidney function in mice and the cut-down cell viability in nephrocyte. Besides, results of murine kidney pathological section and IC50 of two types nephrocyte indicated that OTA-induced toxicity in renal tubule was higher than its in glomeruli. In addition, OTA exposure induced autophagy signaling differentiation expression. It revealed that autophagy was implicated in OTA-induced differential nephrotoxicity in glomeruli and renal tubule. Altogether, we proved that OTA induces a differentiation nephrotoxicity in glomeruli and renal tubule, and it is related to autophagy differential regulation. 相似文献
94.
95.
Xiaoliang Bai Yong Lian Changqing Hu Shuai Yang Bo Pei Mingyan Yao Xiaojuan Zhu Lin Shang Zhihong Li 《Journal of applied toxicology : JAT》2022,42(7):1137-1145
Cyanidin-3-glucoside (C3G) is a well-known natural anthocyanin with antioxidant and anti-inflammatory properties. In this study, we explored the role and action mechanism of C3G in high glucose (HG)-induced damage of human nucleus pulposus cells (HNPCs). Cell viability was assessed by CCK-8 assay. TUNEL assay was performed for detecting apoptotic rate. Western blot was performed to determine the expression levels of cl-caspase-3, caspase-3, Bax, Bim, collagen II, aggrecan, MMP-3, MMP-13, and ADAMTS5. Reactive oxygen species (ROS) generation was analyzed using DCFH-DA staining. The Nrf2 was knocked down or overexpressed in HNPCs through transfection with si-Nrf2 or pcDNA3.0-Nrf2. C3G treatment (12.5, 25, and 50 μM) improved cell viability of HNPCs under HG condition. HG-induced cell apoptosis of HNPCs was attenuated by C3G with decreased apoptotic rate and relative levels of cl-caspase-3/caspase-3, Bax, and Bim. C3G treatment caused significant increase in expression levels of collagen II and aggrecan and decrease in the relative levels of MMP-3, MMP-13, and ADAMTS5. After treatment with C3G, ROS generation in HNPCs was markedly reduced. Treatment with N-acetylcysteine (NAC) reversed HG-induced cell apoptosis and extracellular matrix (ECM) degradation. C3G treatment induced the expression of Nrf2 and HO-1 in HG-induced HNPCs. Moreover, knockdown of Nrf2 reversed the inhibitory effect of C3G on ROS production. Summarily, C3G exerted a protective effect on ROS-mediated cellular damage in HNPCs under HG condition, which was attributed to the induction of the Nrf2/HO-1 signaling pathway. 相似文献
96.
《Vaccine》2022,40(34):4933-4941
Subunit influenza vaccine only formulated with surface antigen proteins has better safety profiles relative to split-virion influenza vaccine. Compared to the traditional quadrivalent split-virion influenza vaccine, a novel quadrivalent subunit influenza vaccine is urgently needed in China. We completed a phase 3, randomized, double-blind, active-controlled, non-inferiority clinical study at two sites in Henan Province, China. Eligible volunteers were split into four age cohorts (3–8 years, 9–17 years, 18–64 years, and ≥ 65 years, based on their dates of birth) and randomly assigned (1:1) to the subunit and the split-virion ecNAIIV4 groups. All volunteers were intramuscularly administered a single vaccine dose at baseline, and children aged 3–8 years received a boosting dose at day 28. And the immune response was evaluated by measuring hemagglutinin-inhibition antibody titers against the four vaccine strains in blood samples. Safety profiles had nonsignificant differences between the study groups in ≥ 3 years cohort. Most adverse reactions post-vaccination, both local and systemic, were mild to moderate and resolved within 3 days. And no serious adverse events occurred. The immunogenicity of the trial vaccine was non-inferior to the comparator. Further, a two-dose vaccine series can provide better seroprotection than that of a one-dose series in children aged 3–8 years, with clinically acceptable safety profiles.Clinical Trials Registration. ChiCTR2100049934. 相似文献
97.
98.
IntroductionDating the exact or estimated time of trauma is an important issue facing forensic medicine. Several clinical and radiological methods were used to achieve this purpose. In the recent study, we aimed to track the changes in the signal intensity of the extra-axial brain hematoma using magnetic resonance imaging (MRI) conventional sequences as well as diffusion-weighted imaging (DWI) and the apparent diffusion coefficient (ADC).Materials and methodsConsidering inclusion and exclusion criteria, all patients with blunt head trauma were involved. After proper management., stabilization, and resuscitation, the participants were assessed using conventional sequences of MRI and DWI twenty-four hours, forty-eight hours, and three weeks after the injury. Temporal changes of signal intensity were compared by Wilcoxon ranged test.ResultsSixteen patients sustaining blunt head trauma were included in this study. The study showed that during the time, diffusion restriction could be seen in an extraaxial hematoma. At the first 24 hours, the signal of hematoma was void in 87.5% of DWI and 100% of ADC. On the second day, they were hypo-signal in 75% of DWI and 100% 0f ADCs, and after three weeks, 100% of cases were hyper-signal in DWI and hypo-signal ADCs.ConclusionThis preliminary study has shown that the DWI can be used to detect and track the extra-axial hematoma. The signal intensity was void during the first twentyfour hours, although it became hypo-signal after 48 hours. Of note, the diffusion restriction is noted after three weeks. 相似文献
99.
《Journal of Cardiovascular Computed Tomography》2022,16(1):51-53
BackgroundThe aortic valve neocuspidalization (AVNeo) is an innovative surgical technique aiming at the reconstruction of the aortic valve using autologous pericardium. One of the main criticisms to AVNeo is the longer duration of the aortic clamping time (ACT) as compared to standard aortic valve replacement due to the sizing of the valve neocusps.MethodsWe retrospectively enrolled 30 consecutives patients underwent AVNeo. For each patient we developed a 3D aortic root model (ARM) based on CT-scan datasets. We retrospectively compared the leaflets measurements performed during surgery with those obtained on the corresponding ARMs.ResultsIn 100% of cases no difference between the in vitro and in vivo measurements exceeded the acceptable error limit of 2 ?mm. The correlation of each single in vitro versus in vivo measurements demonstrates a strong coincidence between the two different methods of sizing (r ?> ?0,9, p ?< ?.0001). By analyzing the data considering the annulus perimeter and not the single cusp size, the perfect coincidence was to be found in 89.9% with a slight acceptable discrepancy (2 ?mm on total) in the remaining 10.1%.Conclusions3D-ARMs, printed from CT-scan, represent a reproducible process to obtain overlapping cusp sizes compared to those measured in-vivo, possibly reducing the ACT. 相似文献
100.