全文获取类型
收费全文 | 1503篇 |
免费 | 41篇 |
国内免费 | 76篇 |
专业分类
耳鼻咽喉 | 10篇 |
儿科学 | 66篇 |
妇产科学 | 14篇 |
基础医学 | 137篇 |
口腔科学 | 22篇 |
临床医学 | 178篇 |
内科学 | 346篇 |
皮肤病学 | 36篇 |
神经病学 | 159篇 |
特种医学 | 261篇 |
外科学 | 118篇 |
综合类 | 29篇 |
预防医学 | 70篇 |
眼科学 | 44篇 |
药学 | 71篇 |
中国医学 | 3篇 |
肿瘤学 | 56篇 |
出版年
2023年 | 7篇 |
2022年 | 5篇 |
2021年 | 8篇 |
2020年 | 7篇 |
2019年 | 15篇 |
2018年 | 15篇 |
2017年 | 10篇 |
2016年 | 20篇 |
2015年 | 21篇 |
2014年 | 23篇 |
2013年 | 35篇 |
2012年 | 29篇 |
2011年 | 49篇 |
2010年 | 54篇 |
2009年 | 65篇 |
2008年 | 46篇 |
2007年 | 73篇 |
2006年 | 52篇 |
2005年 | 42篇 |
2004年 | 36篇 |
2003年 | 31篇 |
2002年 | 31篇 |
2001年 | 36篇 |
2000年 | 42篇 |
1999年 | 22篇 |
1998年 | 88篇 |
1997年 | 74篇 |
1996年 | 64篇 |
1995年 | 56篇 |
1994年 | 53篇 |
1993年 | 50篇 |
1992年 | 34篇 |
1991年 | 25篇 |
1990年 | 39篇 |
1989年 | 49篇 |
1988年 | 51篇 |
1987年 | 33篇 |
1986年 | 31篇 |
1985年 | 30篇 |
1984年 | 24篇 |
1983年 | 16篇 |
1982年 | 20篇 |
1981年 | 11篇 |
1980年 | 16篇 |
1979年 | 10篇 |
1978年 | 10篇 |
1977年 | 17篇 |
1976年 | 16篇 |
1975年 | 14篇 |
1972年 | 4篇 |
排序方式: 共有1620条查询结果,搜索用时 0 毫秒
991.
Differentiation of mouse embryonic stem cells into growth hormone and prolactin expressing cells in vitro 总被引:1,自引:0,他引:1
Embryonic stem (ES) cells provide an excellent in vitro model system to investigate the cellular and molecular events that drive lineage-specific commitment and differentiation and have considerable potential as agents for novel cell-based therapies. While culture methods for directed in vitro differentiation of ES into neuroectodermal and mesodermal derivatives are relatively well established, little is known about the capacity of ES cells to generate the hormone secreting lineages of the pituitary. Here we show that extended culture of adherent embryoid bodies (EBs) results in the induction of pituitary-specific progenitor marker genes and pituitary hormonal markers. GH-expressing cells comprise approximately 2% of the total viable cell population and exhibit dense granular cytoplasmic immunoreactivity. These data demonstrate for the first time that cell types which have the characteristics of pituitary somatotropes and lactotropes can be generated by in vitro differentiation of mouse ES cells. 相似文献
992.
Notch signaling in vascular smooth muscle cells is required to pattern the cerebral vasculature 总被引:1,自引:0,他引:1
Proweller A Wright AC Horng D Cheng L Lu MM Lepore JJ Pear WS Parmacek MS 《Proceedings of the National Academy of Sciences of the United States of America》2007,104(41):16275-16280
Stroke is the third leading cause of death and a significant contributor of morbidity in the United States. In humans, suboptimal cerebral collateral circulation within the circle of Willis (CW) predisposes to ischemia and stroke risk in the setting of occlusive carotid artery disease. Unique genes or developmental pathways responsible for proper CW formation are unknown. Herein we characterize a mouse model lacking Notch signaling in vascular smooth muscle cells (vSMCs), in which the animals are intolerant to reduced cerebral blood flow. Remarkably, unilateral carotid artery ligation results in profound neurological sequelae and death. After carotid ligation, perfusion of the ipsilateral cerebral hemisphere was markedly diminished, suggesting an anastomotic deficiency within the CW. High-resolution microcomputed tomographic (micro-CT) imaging revealed profound defects in cerebrovascular patterning, including interruption of the CW and anatomic deformity of the cerebral arteries. These data identify a vSMC-autonomous function for Notch signaling in patterning and collateral formation within the cerebral arterial circulation. The data further implicate genetic or functional deficiencies in Notch signaling in the pathogenesis of anatomic derangements underlying cerebrovascular accidents. 相似文献
993.
Caroli F Pontillo A D'Osualdo A Travan L Ceccherini I Crovella S Alessio M Stabile A Gattorno M Tommasini A Martini A Lepore L 《Rheumatology (Oxford, England)》2007,46(3):473-478
OBJECTIVE: We report the experience of the Italian Registry of patients affected by chronic infantile neurological, cutaneous, articular (CINCA) syndrome. The clinical and genetic features of 12 unrelated Italian patients with CINCA syndrome are described, focusing on the possible influence of the presence of CIAS1/cryopyrin mutations on the phenotype of the disease and on its prognosis. METHODS: The clinical features of 12 Italian CINCA patients were evaluated. Genomic DNA of the patients was sequenced using specific primers for CIAS1 and ASC genes. RESULTS: Our patients shared typical CINCA characteristics and, sometimes, remarkable perinatal events, peculiar of CIAS1-mutated patients. Seven patients carried CIAS1 missense mutation, localized within the nucleotide binding domain of cryopyrin. Four previously described mutations and three new heterozygous CIAS1 missense mutations were identified. ASC gene, encoding for a direct interactor of cryopyrin, was not mutated in Italian CINCA patients. Finally, we reported the efficacy and safety of anti-IL1 therapy (Anakinra) in seven patients with a particularly severe CINCA phenotype. CONCLUSION: Despite some common signs-used as syndrome hallmarks-we observed a high variability in symptoms, genetic results and outcomes in Italian CINCA patients. In contrast with other authors, we cannot find out any correlation between mutations in CIAS1 and CINCA severity, but we underlined the concomitance of perinatal events and mental retardation only in CIAS1 mutated subjects. Finally, we confirmed the efficacy of Anakinra treatment, both in CIAS1-mutated and non-mutated patients. 相似文献
994.
Linda Petrone Elisa Petruccioli Valentina Vanini Gilda Cuzzi Saeid Najafi Fard Tonino Alonzi Concetta Castilletti Fabrizio Palmieri Gina Gualano Pietro Vittozzi Emanuele Nicastri Luciana Lepore Andrea Antinori Alessandra Vergori Nadia Caccamo Fabrizio Cantini Enrico Girardi Giuseppe Ippolito Delia Goletti 《Clinical microbiology and infection》2021,27(2):286.e7-286.e13
ObjectivesTo examine whether specific T-cell-responses to SARS-CoV-2 peptides can be detected in COVID-19 using a whole-blood experimental setting, which may be further explored as a potential diagnostic tool.MethodsWe evaluated interferon (IFN)-γ levels after stimulating whole-blood with spike and remainder-antigens peptides megapools (MP) derived from SARS-CoV-2 sequences; interleukin (IL)-1β, IL-1RA, IL-2, IL-4, IL-5, IL-6, IL-7, IL-8, IL-9, IL-10, IL-12p70, IL-13, IL-15, IL-17A, eotaxin, basic fibroblast growth factor (FGF), granulocyte-colony stimulating factor (G-CSF), granulocyte-macrophage colony-stimulating factor (GM-CSF), IFN-γ, Interferon gamma-induced protein 10 (IP-10), monocyte chemoattractant protein-1 (MCP-1), macrophage inflammatory protein (MIP)-1α, MIP-1β, Platelet-derived growth factor (PDGF), RANTES (regulated on activation, normal T cell expressed and secreted), tumour necrosis factor-alpha (TNF-α), vascular endothelial growth factor (VEGF) were also evaluated.ResultsIFN-γ-response to spike and remainder-antigens MPs was significantly increased in 35 COVID-19 patients compared with 29 ‘no COVID-19’ individuals (medians spike-MP: 0.26 vs 0, p = 0.0002; medians remainder-antigens-MP: 0.07 vs 0.02; p = 0.02).This response was detected independently of patients' clinical parameters. IFN-γ-response to SARS-CoV-2-unrelated antigens cytomegalovirus (CMV) and Staphylococcal Enterotoxin B (SEB) was similar in COVID-19 compared with ‘no COVID-19’ individuals (median CMV: 3.46 vs 5.28, p = 0.16; median SEB: 12.68 vs 15.05; p = 0.1). In response to spike-MPs in COVID-19- compared with ‘no COVID-19’ -individuals, we found significant higher median of IL-2 (50.08 vs 0, p = 0.0018), IFN-γ (90.16 vs 0, p = 0.01), IL-4 (0.52 vs 0, p = 0.03), IL-13 (0.84 vs 0, p = 0.007) and MCP-1 (4602 vs 359.2, p = 0.05).ConclusionsImmune response to SARS-CoV-2 peptides in a whole-blood assay is associated with COVID-19 and it is characterized by both Th1 and Th2 profile. This experimental approach may be useful for developing new T-cell based diagnostic tests for disease and vaccine settings. 相似文献
995.
996.
气相色谱法测定感冒解表口服液中百秋李醇含量的研究 总被引:3,自引:0,他引:3
目的:建立气相色谱法测定感冒解表口服液中百秋李醇含量的方法。方法:样品经提了挥发油后用气相色谱法测定。色谱条件;以10%PEG-20M作固定液,程序升温。以正十八烷为人标,FID检测。结果;线性范围0.2-1.7mg,缺味空白无干扰,加样回收率为97.7%,RSD为2.87。结论;用程序升温气相谱法测定本法简便,灵敏度高,重现性好,可用于质量控制。 相似文献
997.
998.
999.
1000.