全文获取类型
收费全文 | 879篇 |
免费 | 41篇 |
国内免费 | 2篇 |
专业分类
耳鼻咽喉 | 20篇 |
儿科学 | 16篇 |
妇产科学 | 20篇 |
基础医学 | 117篇 |
口腔科学 | 55篇 |
临床医学 | 81篇 |
内科学 | 197篇 |
皮肤病学 | 27篇 |
神经病学 | 58篇 |
特种医学 | 32篇 |
外科学 | 106篇 |
综合类 | 5篇 |
一般理论 | 4篇 |
预防医学 | 54篇 |
眼科学 | 18篇 |
药学 | 62篇 |
中国医学 | 6篇 |
肿瘤学 | 44篇 |
出版年
2024年 | 2篇 |
2023年 | 12篇 |
2022年 | 33篇 |
2021年 | 78篇 |
2020年 | 30篇 |
2019年 | 34篇 |
2018年 | 48篇 |
2017年 | 44篇 |
2016年 | 35篇 |
2015年 | 38篇 |
2014年 | 56篇 |
2013年 | 54篇 |
2012年 | 99篇 |
2011年 | 69篇 |
2010年 | 54篇 |
2009年 | 40篇 |
2008年 | 40篇 |
2007年 | 41篇 |
2006年 | 34篇 |
2005年 | 21篇 |
2004年 | 19篇 |
2003年 | 14篇 |
2002年 | 16篇 |
1998年 | 4篇 |
1997年 | 3篇 |
1996年 | 1篇 |
1995年 | 1篇 |
1994年 | 1篇 |
1986年 | 1篇 |
排序方式: 共有922条查询结果,搜索用时 15 毫秒
41.
42.
Omid Asbaghi Behzad Nazarian
eljko Reiner Elaheh Amirani Fariba Kolahdooz Maryam Chamani Zatollah Asemi 《Phytotherapy research : PTR》2020,34(2):239-253
The aim of this systematic review and meta‐analysis was to analyze the effects of grape seed extract (GSE) on glycemic control and serum lipoproteins, inflammation and body weight. Two independent authors systematically searched online databases including EMBASE, Scopus, PubMed, Cochrane Library, and Web of Science from inception until May 30, 2019. Cochrane Collaboration risk of bias tool was applied to assess the methodological quality of included trials. The heterogeneity among the included studies was assessed using Cochrane's Q test and I‐square (I2) statistic. Data were pooled using a random‐effects model and weighted mean difference (WMD) was considered as the overall effect size. Fifty trials were included in this meta‐analysis. Pooling effect sizes from studies demonstrated a significant decrease in fasting plasma glucose (FPG) (WMD): ?2.01; 95% confidence interval (CI): ?3.14, ?0.86), total cholesterol (TC; WMD: ?6.03; 95% CI: ?9.71, ?2.35), low‐density lipoprotein (LDL) cholesterol (WMD: ?4.97; 95% CI: ?8.37, ?1.57), triglycerides (WMD: ?6.55; 95% CI: ?9.28, ?3.83), and C‐reactive protein (CRP) concentrations (WMD: ?0.81; 95% CI: ?1.25, ?0.38) following GSE therapy. Grape seed did not influence HbA1c, HDL cholesterol levels, and anthropometric measurements. This meta‐analysis demonstrated that GSE intake significantly reduced FPG, TC, LDL cholesterol, triglycerides, and CRP levels. 相似文献
43.
Mohammad Hassanpour Seyed Ali Hosseini Tafreshi Omid Amiri Masood Hamadanian Masoud Salavati-Niasari 《RSC advances》2021,11(44):27283
The presence of nanoparticles in the environment and their impact on existing organisms is one of the main concerns of researchers working in this field. In this research, Nd2WO6 nanoparticles were prepared by an ultrasonic procedure for the first time. X-ray powder diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), and energy-dispersive X-ray spectroscopy (EDS) analyses were applied to identify and prove the purity of these particles. In addition to increasing the reaction rate and efficiency with the help of a radical generation mechanism, ultrasound was able to aid the synthesis of these particles. After confirming nanoparticle formation, the optimal nanoparticles in view of scale and morphology were selected by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Optimal particles at three concentrations (25, 50, and 100 ppm) were mixed into the algae growth medium to investigate the effects of the nanoparticles on Dunaliella salina growth. Biological parameters, including the number of cells, biomass, specific growth rate, pigments, and malondialdehyde (MDA), were measured after ten days. Growth parameters showed an increasing trend in concentrations up to 50 ppm; however, at a concentration of 100 ppm, a significant decrease was observed in contrast to the nanoparticles-free treatment. The MDA content showed a linear relationship with enhanced concentration of the nanoparticles. The examination of biological parameters showed that the algae response to stress was dependent on the concentration of nanoparticles. The results showed that 50 ppm of nanoparticles are suitable for increasing algae and achieving a suitable growth rate for commercial purposes. However, in higher concentrations, algal growth inhibition occurs, which is of great importance from a biotechnological point of view.In this work, Nd2WO6 nanoparticles were synthesized by the ultrasonic method for the first time. Also, for the first time, the impact of these nanoparticles on the environment was investigated. 相似文献
44.
Holger Lubatschowski Omid Kermani Cornelius Often Andreas Haller Karl Christian Schmiedt Wolfgang Ertmer 《Lasers in surgery and medicine》1994,14(2):168-177
Secondary radiation, emitted during and after the irradiation of corneal, dermal, and dental tissue by an ArF-excimer laser (193 nm), was qualitatively and quantitatively characterized. Emission of secondary radiation was found in the range of 200–800 nm. The intensity of secondary radiation in the range of 200–315 nm (UVC and UVB) is ∼20% of the total intensity at high laser fluences (>2 J/cm2), and ∼50% at moderate laser fluences (<500 mJ/cm2); 10 μJ/cm2 in the UVC and UVB were measured at the sample surface, at fluences (<1J/cm2) which are of relevance for clinical procedures on soft tissues. In dental tissue processing, very high fluences (>5 J/cm2) are required. As a consequence, laser–induced plasma formation can be observed. Secondary radiation can be used as a visible guide for selective removal of carious altered tissue. The data we have found might be of assistance in estimating potential hazards for future mutagenic studies in the field. © 1994 Wiley-Liss, Inc. 相似文献
45.
46.
47.
48.
Omid Ahmadi Martha De L Nicholson Maree L Gould Allan Mitchell Mark D Stringer 《Journal of gastroenterology and hepatology》2010,25(2):277-285
Background and Aims: Interstitial cells of Cajal (ICC) are distributed with smooth muscle throughout the gastrointestinal tract and are involved in regulating motility. ICC were recently discovered in the wall of the human gallbladder. This study sought to determine whether ICC are present in human bile ducts. Methods: Biliary tract samples were obtained from several sources: surgical specimens (n = 16, 11 women, mean age 61 years); archival post‐mortem specimen (n = 1, 86 years, man); and cadavers (n = 2, 68 and 80 years, men). Paraffin‐embedded sections (3 µm) from the gallbladder (fundus, body and neck) and both extrahepatic and intrahepatic bile ducts were investigated. A double immunofluorescence protocol using polyclonal and monoclonal c‐kit antibodies and mast cell tryptase was used to distinguish c‐kit‐positive cells with typical ICC morphology from c‐kit‐positive mast cells. Small bowel samples were used as positive controls. ICC in the gallbladder were confirmed by ultrastructural study. Results: c‐kit‐positive cells with characteristic ICC morphology were identified in the subepithelial and muscular layers of the gallbladder and extrahepatic bile ducts. They were most prominent within the muscle layer of the extrahepatic bile ducts where they were organized into loosely arranged laminae running parallel to circular smooth muscle fibers. ICC were not found in intrahepatic bile ducts. Conclusion: This study demonstrates for the first time that ICC are present in human extrahepatic bile ducts where they are more densely aggregated than in the gallbladder. This cellular network is likely to be involved in biliary tract motility and its related disorders. 相似文献
49.
50.