全文获取类型
收费全文 | 2658篇 |
免费 | 204篇 |
国内免费 | 354篇 |
专业分类
耳鼻咽喉 | 4篇 |
儿科学 | 16篇 |
妇产科学 | 28篇 |
基础医学 | 399篇 |
口腔科学 | 27篇 |
临床医学 | 148篇 |
内科学 | 228篇 |
皮肤病学 | 7篇 |
神经病学 | 122篇 |
特种医学 | 25篇 |
外科学 | 93篇 |
综合类 | 596篇 |
预防医学 | 309篇 |
眼科学 | 21篇 |
药学 | 760篇 |
3篇 | |
中国医学 | 328篇 |
肿瘤学 | 102篇 |
出版年
2024年 | 13篇 |
2023年 | 71篇 |
2022年 | 112篇 |
2021年 | 154篇 |
2020年 | 163篇 |
2019年 | 121篇 |
2018年 | 79篇 |
2017年 | 113篇 |
2016年 | 134篇 |
2015年 | 154篇 |
2014年 | 252篇 |
2013年 | 256篇 |
2012年 | 252篇 |
2011年 | 242篇 |
2010年 | 203篇 |
2009年 | 176篇 |
2008年 | 205篇 |
2007年 | 255篇 |
2006年 | 45篇 |
2005年 | 9篇 |
2004年 | 9篇 |
2003年 | 17篇 |
2002年 | 21篇 |
2001年 | 20篇 |
2000年 | 6篇 |
1999年 | 24篇 |
1998年 | 15篇 |
1997年 | 25篇 |
1996年 | 13篇 |
1995年 | 14篇 |
1994年 | 12篇 |
1993年 | 5篇 |
1992年 | 5篇 |
1991年 | 5篇 |
1990年 | 6篇 |
1989年 | 6篇 |
1988年 | 4篇 |
排序方式: 共有3216条查询结果,搜索用时 46 毫秒
21.
22.
X. L. Xu Q. M. Xie Y. H. Shen J. J. Jiang Y. Y. Chen H. Y. Yao J. Y. Zhou 《Inflammation research》2008,57(3):104-110
Objective: To investigate the effect of mannose on lipopolysaccharide (LPS) induced acute lung injury (ALI) in rats.
Methods: Ten groups of Sprague–Dawley rats were used: 1) the control group received an intratracheal instillation of saline, 2) the LPS group received an intratracheal instillation of LPS (3 mg/kg), 3–6) the mannose groups were injected i.v. with 15, 45, 135, and 405 mg/kg mannose, 7–9) the glucose, galactose, and fructose groups were injected with different hexoses (135 mg/kg), and 10) the dexamethasone (DXM) group was injected with DXM (2 mg/kg). In groups 2–8, LPS was administered after injection of drugs.
Lung wet/dry weight ratio, permeability index (PPI), total leukocytes and polymorphonuclear neutrophils (PMNs) counts in bronchoalveolar
lavage fluid (BALF), myeloperoxidase (MPO) and superoxide dismutase (SOD) activity, tumor necrosis factor (TNF)-α and interleukin
(IL)-10 in lung and BALF were determined.
Results: Pre-treatment with mannose attenuated pulmonary edema and protein exudation in a dose-dependent manner, the maximal effect
was similar to or greater than that of DXM. Mannose also prevented the inflammatory cell accumulation, although the maximal
effect was weaker than that of DXM. Mannose was more effective than DXM in inhibiting MPO activity and restoring SOD activity.
Moreover, it inhibited production of TNF-α and IL-10. Histological changes of the lungs were also ameliorated by mannose.
There were no significant improvements observed in rats pre-treated with glucose, galactose or fructose.
Conclusions: Mannose is effective in reducing LPS-induced ALI.
Project supported by the National Natural Science Foundation of China, No. 30670930 and the Science and Technology Department
of Zhejiang Province (No.2004C23011)
Received 4 March 2007; returned for revision 13 May 2007; returned for final revision 17 July 2007; accepted by M. Katori
12 September 2007 相似文献
23.
胃癌伴神经内分泌分化的研究进展 总被引:2,自引:0,他引:2
胃癌发生发展过程中,部分癌细胞会表达神经内分泌颗粒,出现神经内分泌分化现象。多数研究认为,神经内分泌(neuroendocrine,NE)细胞和上皮细胞均来自内胚层多潜能干细胞,是肿瘤发生过程中干细胞多向分化的结果。神经内分泌分化机制可能与Neuro D转录因子、突触间囊泡蛋白2、 menin蛋白、Reg Iv(Regenerating gene Iv)基因、p53的突变和bcl-2基因的表达有关。 相似文献
24.
热休克蛋白(HSP)是一类在生物进化中高度保守、广泛存在于原核和真核生物中的蛋白质。大量资料表明,HSP作为分子伴侣,参与其它蛋白质的折叠、转运、合成等过程,并可与细胞内的其它蛋白质结合,参与细胞的抗损伤、修复和热耐受过程,某些热休克蛋白还具有佐剂效应,能够激活免疫应答反应,以往对于HSP70及其免疫治疗的研究较为广泛。近年来随着对热休克蛋白研究的不断深入,人们发现高分子量的HSP110因其强大的分子伴侣功能而具备独特的佐剂效应,因而被认为在瘤苗制备及抗肿瘤免疫中具有很大的应用前景。 相似文献
25.
《Environmental toxicology and pharmacology》2014,37(2):697-704
The objective of this study was to assess potential toxic effects of phenanthrene (PHE) on tissues of clam Venerupis philippinarum using parameters of antioxidant defenses and oxidative stress. Antioxidant biomarkers including ethoxyresorufin-O-deethylase (EROD), glutathione S-transferase (GST), superoxide dismutase (SOD), and glutathione (GSH), as well as DNA damage and lipid peroxidation (LPO) in gills and digestive glands of V. philippinarum, were analyzed after a 1-, 3-, 6-, 10- and 15-day exposure to seawater containing PHE at concentrations of 2, 10, 50 μg/L. The results showed that the activity of most antioxidant enzymes was induced throughout the exposure period, and different trends were detected with time of exposure. The oxidative stress could be obviously caused in the gills and digestive glands under the experimental conditions. Overall, our results show that digestive glands are more sensitive to marine environmental stressors than gills, and GSH is proposed as potential useful biomarker as it showed good correlation with the target contaminant. This could provide useful information for toxic risk assessment of environmental pollutant PHE. 相似文献
26.
《Environmental toxicology and pharmacology》2014,37(3):1304-1311
Antileishmanial in vitro tests, as well as Ames and micronucleus assays were performed with a concentrated ethanolic extract of Physalis angulata (EEPA)ResultsEEPA did not present mutagenic effect in Salmonella typhimurium strains at concentration reaching 3000 μg/plate and did not induce mutagenic effects after two oral administrations with a 24 h interval at a dose level of 2000 mg/kg. EEPA presented antileishmanial activity and presented an IC50 value of 5.35 ± 2.50 μg/mL and 4.50 ± 1.17 μg/mL against Leishmania amazonensis and Leishmania braziliensis promastigotes, respectively. In the cytotoxicity test against macrophages, the EEPA had a LC50 of 6.14 ± 0.59 μg/mL. Importantly, the IC50 against L. amazonensis intracellular amastigotes was 1.23 ± 0.11 μg/mL.ConclusionEEPA extract is non-mutagenic and presented a promising pharmacological effect against Leishmania parasites. 相似文献
27.
《Drug discovery today》2014,19(12):1848-1854
28.
Shao Hua YU Jun Peng ZHU You XU Lei Lei ZHENG Hao CHAI Wei HE Wei Bo LIU Hui Chun LI Wei WANG 《Biomedical and environmental sciences : BES》2012,25(6):697-705
ObjectiveTo study the contribution of executive function to abnormal recognition of facial expressions of emotion in schizophrenia patients.MethodsAbnormal recognition of facial expressions of emotion was assayed according to Japanese and Caucasian facial expressions of emotion (JACFEE), Wisconsin card sorting test (WCST), positive and negative symptom scale, and Hamilton anxiety and depression scale, respectively, in 88 paranoid schizophrenia patients and 75 healthy volunteers.ResultsPatients scored higher on the Positive and Negative Symptom Scale and the Hamilton Anxiety and Depression Scales, displayed lower JACFEE recognition accuracies and poorer WCST performances. The JACFEE recognition accuracy of contempt and disgust was negatively correlated with the negative symptom scale score while the recognition accuracy of fear was positively with the positive symptom scale score and the recognition accuracy of surprise was negatively with the general psychopathology score in patients. Moreover, the WCST could predict the JACFEE recognition accuracy of contempt, disgust, and sadness in patients, and the perseverative errors negatively predicted the recognition accuracy of sadness in healthy volunteers. The JACFEE recognition accuracy of sadness could predict the WCST categories in paranoid schizophrenia patients.ConclusionRecognition accuracy of social-/moral emotions, such as contempt, disgust and sadness is related to the executive function in paranoid schizophrenia patients, especially when regarding sadness. 相似文献
29.
30.
《Immunobiology》2017,222(2):394-398
It has been established that mesenchymal stem cells (MSCs) can have a suppressive effect on T cells, yet much remains unknown about the underlying mechanisms that support this effect. The T cell co-stimulatory pathway involving the programmed death-1 (PD-1) receptor and its ligand PD-L1 regulates T cell activation, tolerance, and subsequent immune-mediated tissue damage. In this study, human palatine tonsil-derived MSCs (T-MSCs) constitutively expressed PD-L1 and exhibited a suppressive activity that specifically targeted murine Th17 differentiation. Additionally, polyinosinic–polycytidylic acid (poly I:C), a Toll-like receptor 3 (TLR3) ligand, increased PD-L1 expression on T-MSCs. The elevated PD-L1 levels enhanced the suppressive functions of T-MSCs on Th17 differentiation. Therefore, pre-stimulation of T-MSCs with poly I:C may serve as an effective therapeutic priming step for modulating Th17-dominant immune responses. 相似文献