全文获取类型
收费全文 | 7858篇 |
免费 | 531篇 |
国内免费 | 325篇 |
专业分类
耳鼻咽喉 | 45篇 |
儿科学 | 89篇 |
妇产科学 | 29篇 |
基础医学 | 842篇 |
口腔科学 | 151篇 |
临床医学 | 527篇 |
内科学 | 743篇 |
皮肤病学 | 578篇 |
神经病学 | 1724篇 |
特种医学 | 223篇 |
外科学 | 440篇 |
综合类 | 809篇 |
现状与发展 | 2篇 |
预防医学 | 398篇 |
眼科学 | 248篇 |
药学 | 1277篇 |
1篇 | |
中国医学 | 367篇 |
肿瘤学 | 221篇 |
出版年
2024年 | 37篇 |
2023年 | 167篇 |
2022年 | 297篇 |
2021年 | 394篇 |
2020年 | 312篇 |
2019年 | 270篇 |
2018年 | 256篇 |
2017年 | 243篇 |
2016年 | 279篇 |
2015年 | 272篇 |
2014年 | 421篇 |
2013年 | 507篇 |
2012年 | 421篇 |
2011年 | 455篇 |
2010年 | 382篇 |
2009年 | 355篇 |
2008年 | 364篇 |
2007年 | 337篇 |
2006年 | 329篇 |
2005年 | 258篇 |
2004年 | 191篇 |
2003年 | 194篇 |
2002年 | 165篇 |
2001年 | 162篇 |
2000年 | 140篇 |
1999年 | 126篇 |
1998年 | 117篇 |
1997年 | 119篇 |
1996年 | 93篇 |
1995年 | 78篇 |
1994年 | 79篇 |
1993年 | 66篇 |
1992年 | 71篇 |
1991年 | 69篇 |
1990年 | 40篇 |
1989年 | 63篇 |
1988年 | 54篇 |
1987年 | 55篇 |
1986年 | 66篇 |
1985年 | 59篇 |
1984年 | 68篇 |
1983年 | 42篇 |
1982年 | 53篇 |
1981年 | 47篇 |
1980年 | 46篇 |
1979年 | 31篇 |
1978年 | 24篇 |
1977年 | 11篇 |
1976年 | 12篇 |
1975年 | 6篇 |
排序方式: 共有8714条查询结果,搜索用时 15 毫秒
51.
Objective: To determine the encephalic region correlated with epilepsy by manganese-enhanced MRI (MEMRI) and determine the correlation of epilepsy with calcium overloading. Methods: The cats were divided into two groups. The first group underwent EEG examination and ethological observation. The second group underwent MEMRI measurement. Signal enhanced encephalic regions were sectioned. Results: The achievement ratio of convulsive cats intramusclelarly injected with PTZ was 80%. MEMRI showed diffuse signal enhancement in the cerebral cortex of the cats with generalized tonic-clonic convulsive seizures compared with control animals. The enhancement rate of frontal-parietal-occipital lobe was 34.6% and 22.9% in temporl lobe compared with the control groups. Signal enhancement on frontal-parietal lobe persisted for 24 h after epileptic seizures were induced. The neurons of enhanced encephalic regions showed obvious degeneration and necrosis. Conclusion: Seizures can be induced in cats by intramuscular injection of PTZ (55 mg/kg). Frontal-parietal lobe is the correlated encephalic regions of epilepsy. MEMRI plays an important role in localizing and revealing pathogenesis of epileptic seizures. 相似文献
52.
目的 分析急性生理与慢性健康状况系统Ⅱ(APACHEⅡ)评分与重度有机磷中毒患者肠道屏障功能的相关性.方法 回顾性选取2017年1月至2019年12月安徽理工大学附属亳州市人民医院收治的119例重度有机磷中毒患者.按照患者预后情况,将患者分别纳入存活组80例、病死组39例.记录患者入院即刻及入院48、72、144 h ... 相似文献
53.
目的 观察多药耐药蛋白1(muhidrug resistance 1,MDR1)、多药耐药相关蛋白(multidrug resistance-associated protein,MRP)5和MRP7在不同时期糖尿病小鼠视网膜中的表达变化.方法 通过腹腔注射链脲佐菌素诱导C57 BL/6小鼠建立糖尿病模型,伊文思蓝灌注检测血-视网膜内屏障变化.分别于糖尿病造模成功后的4周、12周和24周取小鼠视网膜,进行实时定量-PCR、免疫荧光、Western blotting等实验,检测各组小鼠视网膜中MDR1、MRP5和MRP7的表达变化.结果 伊文思蓝灌注结果显示在糖尿病12周就出现视网膜渗漏;实时定量-PCR结果发现与对照组相比,随糖尿病进展,MDR1、MRP5和MRP7在4周、12周和24周的表达均呈下降趋势(MDR1:P4周=0.028,P12周=0.003,P24周<0.001;MRP5:P4周=0.045,P12周=0.009,P24周<0.001;MRPy7:P4周=0.019,P12周<0.001,P24周 =0.001),在糖尿病不同时期其变化也呈下降趋势(均为P<0.05);免疫荧光观察到MDR1、MRP5和MRP7的荧光强度随糖尿病发展逐渐减弱;Western blotting检测可见在4周、12周、24周糖尿病小鼠视网膜中MDR1、MRP5和MRP7的表达均呈下降趋势.结论 在DR早期血-视网膜内屏障会受到破坏,视网膜中外排转运蛋白的表达也会受糖尿病的影响导致不同程度的下降. 相似文献
54.
55.
Astrocytes in the damaged brain: Molecular and cellular insights into their reactive response and healing potential 总被引:1,自引:0,他引:1
Long considered merely a trophic and mechanical support to neurons, astrocytes have progressively taken the center stage as their ability to react to acute and chronic neurodegenerative situations became increasingly clear. Reactive astrogliosis starts when trigger molecules produced at the injury site drive astrocytes to leave their quiescent state and become activated. Distinctive morphological and biochemical features characterize this process (cell hypertrophy, upregulation of intermediate filaments, and increased cell proliferation). Moreover, reactive astrocytes migrate towards the injured area to constitute the glial scar, and release factors mediating the tissue inflammatory response and remodeling after lesion. A novel view of astrogliosis derives from the finding that subsets of reactive astrocytes can recapitulate stem cell/progenitor features after damage, fostering the concept of astroglia as a promising target for reparative therapies. But which biochemical/signaling pathways modulate astrogliosis with respect to both the time after injury and the type of damage? Are reactive astrocytes overall beneficial or detrimental for neuroprotection and tissue regeneration? This debate has been animating this research field for several years now, and an integrated view on the results obtained and the possible future perspectives is needed. With this Commentary article we have attempted to answer the above-mentioned questions by reviewing the current knowledge on the molecular mechanisms controlling and sustaining the reaction of astroglia to injury and its stem cell-like properties. Moreover, the cellular/molecular mechanisms supporting the detrimental or beneficial features of astrogliosis have been scrutinized to gain insights on possible pharmacological approaches to enhance astrocyte neuroprotective activities. 相似文献
56.
Mengdi Zhang Jianhua Liu Chen Li Jianwei Gao Chuanhui Xu Xiaoyu Wu Tiesheng Xu Chenbin Cui Hongkui Wei Jian Peng Rong Zheng 《Nutrients》2022,14(13)
Obesity may cause metabolic syndrome and has become a global public health problem, and dietary fibers (DF) could alleviate obesity and metabolic syndrome by regulating intestinal microbiota. We developed a functional fiber (FF) with a synthetic mixture of polysaccharides, high viscosity, water-binding capacity, swelling capacity, and fermentability. This study aimed to investigate the effect of FF on obesity and to determine its prevention of obesity by modulating the gut microbiota. Physiological, histological, and biochemical parameters, and gut microbiota composition were investigated in the following six groups: control group (Con), high-fat diet group (HFD), low-fat diet group (LFD, conversion of HFD to LFD), high-fat +8% FF group (8% FF), high-fat +12% FF group (12% FF), and high-fat +12% FF + antibiotic group (12% FF + AB). The results demonstrated that 12% FF could promote a reduction in body weight and epididymal adipocyte area, augment insulin sensitivity, and stimulate heat production from brown adipose tissue (BAT) (p < 0.05). Compared with the HFD, 12% FF could also significantly improve the intestinal morphological integrity, attenuate systemic inflammation, promote intestinal microbiota homeostasis, and stabilize the production of short-chain fatty acids (SCFAs) (p < 0.05). Consistent with the results of 12% FF, the LFD could significantly reduce the body weight and epididymal adipocyte area relative to the HFD (p < 0.05), but the LFD and HFD showed no significant difference (p > 0.05) in the level of inflammation and SCFAs. Meanwhile, 12% FF supplementation showed an increase (p < 0.05) in the abundance of the Bifidobacterium, Lactococcus, and Coprococcus genus in the intestine, which had a negative correlation with obesity and insulin resistance. Additionally, the treatment with antibiotics (12% FF + AB) could inhibit the effect of FF in the HFD. The Kyoto Encyclopedia of Genes and Genomes (KEGG) function prediction revealed that 12% FF could significantly inhibit the cyanogenic amino acid metabolic pathway and decrease the serum succinate concentration relative to the HFD group. The overall results indicate that 12% FF has the potential to reduce obesity through the beneficial regulation of the gut microbiota and metabolites. 相似文献
57.
《Expert opinion on drug delivery》2013,10(7):889-905
Introduction: With the advancement in the field of medical colloids and interfacial sciences, the life expectancy has been greatly improved. In addition, changes in the human lifestyle resulted in development of various organic and functional disorders. Central nervous system (CNS) disorders are most prevalent and increasing among population worldwide. The neurological disorders are multi-systemic and difficult to treat as portal entry to brain is restricted on account of its anatomical and physiological barrier. Areas covered: The present review discusses the limitations to CNS drug delivery, and the various approaches to bypass the blood brain barrier (BBB), focusing on the potential use of solid lipid nanoparticles (SLN) for drug targeting to brain. The methods currently in use for SLN production, physicochemical characterization and critical issues related to the formulation development suitable for targeting brain are also discussed. Expert opinion: The potential advantages of the use of SLN over polymeric nanoparticles are due to their lower cytotoxicity, higher drug loading capacity and scalability. In addition, their production is cost effective and the systems provide a drug release in a controlled manner up to several weeks. Drug targeting potential of SLN can be enhanced by attaching ligands to their surface. 相似文献
58.
Xiao-chang LIU Qiao MEI Jian-ming XU Jing HU 《中国药理学报》2009,(7):987-993
Aim: To investigate the effect of balsalazine treatment on intestinal mucosal permeability in dextran sulfate sodium (DSS)-induced colitis and to determine the mechanism of the balsalazine-induced changes.
Methods: Experimental colitis was induced in C57BL/6J mice by the administration of 5% DSS. Balsalazine was administered intragastrically at doses of 42, 141, and 423 mg/kg. The disease activity index (DAI) score was evaluated and colon tissue was collected for the assessment of histological changes. The amount of malondialdehyde (MDA) in the colon was determined, along with the activity of myeloperoxidase (MPO), superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px). Mucosa from the small intestine was collected to determine the levels of tumor necrosis factor (TNF)-α and interferon (IFN)-γ. The mucosa was ultrastructurally examined with transmission electron microscopy and intestinal permeability was assayed using Evans blue.
Results: Balsalazine was found to reduce the DAI score and the histological index (HI) score, decrease the MDA content and the activity of MPO, and increase the activity of SOD and GSH-Px in colitis mice. At the same time, balsalazine ameliorated microvillus and tight junction structure, resulting in a decrease in the amount of Evans blue permeating into the intestinal wall and the levels of TNF-α and IFN-γ in colitis mice.
Conclusion: In colitis mice, the anti-colitis effect of balsalazine results in a decrease in intestinal mucosal permeability. The mechanism of this effect is partly associated with balsalazine's antioxidative and anti-inflammatory effects. 相似文献
Methods: Experimental colitis was induced in C57BL/6J mice by the administration of 5% DSS. Balsalazine was administered intragastrically at doses of 42, 141, and 423 mg/kg. The disease activity index (DAI) score was evaluated and colon tissue was collected for the assessment of histological changes. The amount of malondialdehyde (MDA) in the colon was determined, along with the activity of myeloperoxidase (MPO), superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px). Mucosa from the small intestine was collected to determine the levels of tumor necrosis factor (TNF)-α and interferon (IFN)-γ. The mucosa was ultrastructurally examined with transmission electron microscopy and intestinal permeability was assayed using Evans blue.
Results: Balsalazine was found to reduce the DAI score and the histological index (HI) score, decrease the MDA content and the activity of MPO, and increase the activity of SOD and GSH-Px in colitis mice. At the same time, balsalazine ameliorated microvillus and tight junction structure, resulting in a decrease in the amount of Evans blue permeating into the intestinal wall and the levels of TNF-α and IFN-γ in colitis mice.
Conclusion: In colitis mice, the anti-colitis effect of balsalazine results in a decrease in intestinal mucosal permeability. The mechanism of this effect is partly associated with balsalazine's antioxidative and anti-inflammatory effects. 相似文献
59.
60.
目的探讨肠内营养合早期中药干预对胃大部切除大鼠肠道细胞更新状态指标(肠道黏膜细胞凋亡率)的影响及机制。方法将60只雄性SD大鼠建立胃大部切除模型,随机分成对照组(C),普通肠内营养组(EN组),肠内营养加四君子汤组(S-EN组)。从术后第1天起连续营养支持7 d,各组营养液的热量、含氮量均相同。观察术前1 d、术后1 d、3 d、7 d的肠道细胞更新状态指标(肠道黏膜细胞凋亡率)的变化。结果S-EN组术后3 d后肠道黏膜细胞凋亡率显著高于C组和EN组(P<0.05)。结论肠内营养合早期中药(四君子汤)干预可提高术后大鼠的营养状态和肠道细胞更新状态,明显改善肠黏膜屏障功能。 相似文献