全文获取类型
收费全文 | 818篇 |
免费 | 50篇 |
国内免费 | 5篇 |
专业分类
耳鼻咽喉 | 6篇 |
儿科学 | 42篇 |
妇产科学 | 7篇 |
基础医学 | 70篇 |
口腔科学 | 65篇 |
临床医学 | 98篇 |
内科学 | 112篇 |
皮肤病学 | 10篇 |
神经病学 | 11篇 |
特种医学 | 189篇 |
外科学 | 47篇 |
综合类 | 74篇 |
预防医学 | 47篇 |
眼科学 | 6篇 |
药学 | 43篇 |
中国医学 | 24篇 |
肿瘤学 | 22篇 |
出版年
2022年 | 6篇 |
2021年 | 2篇 |
2020年 | 6篇 |
2019年 | 3篇 |
2018年 | 15篇 |
2017年 | 13篇 |
2016年 | 11篇 |
2015年 | 11篇 |
2014年 | 26篇 |
2013年 | 50篇 |
2012年 | 43篇 |
2011年 | 38篇 |
2010年 | 42篇 |
2009年 | 35篇 |
2008年 | 34篇 |
2007年 | 49篇 |
2006年 | 15篇 |
2005年 | 11篇 |
2004年 | 9篇 |
2003年 | 2篇 |
2002年 | 8篇 |
2001年 | 9篇 |
2000年 | 6篇 |
1999年 | 15篇 |
1998年 | 56篇 |
1997年 | 47篇 |
1996年 | 36篇 |
1995年 | 23篇 |
1994年 | 26篇 |
1993年 | 23篇 |
1992年 | 7篇 |
1991年 | 9篇 |
1990年 | 6篇 |
1989年 | 19篇 |
1988年 | 23篇 |
1987年 | 21篇 |
1986年 | 15篇 |
1985年 | 22篇 |
1984年 | 7篇 |
1983年 | 10篇 |
1982年 | 10篇 |
1981年 | 8篇 |
1980年 | 10篇 |
1978年 | 6篇 |
1977年 | 6篇 |
1976年 | 9篇 |
1975年 | 7篇 |
1969年 | 1篇 |
1968年 | 1篇 |
1954年 | 1篇 |
排序方式: 共有873条查询结果,搜索用时 10 毫秒
101.
102.
103.
104.
Inhibition of thromboxane formation in vivo and ex vivo: implications for therapy with platelet inhibitory drugs 总被引:7,自引:1,他引:7
The capacity of platelets to generate thromboxane A2, reflected by measurement of serum thromboxane B2 (TxB2), greatly exceeds the systemic production of thromboxane in vivo. Thus, it is possible that substantial but incomplete inhibition of thromboxane formation ex vivo would still allow marked augmentation of thromboxane production in vivo. To address this hypothesis, we administered aspirin 120 mg, a selective inhibitor of thromboxane synthase (TxSl), 3-(1H-imidazol-1-yl- methyl)-2-methyl-1H-indole-1-propanoic acid (UK-38, 485) 200 mg, and a combination of both drugs to 12 healthy volunteers and measured the effects on serum TxB2 and urinary 2,3-dinor-thromboxane B2 (Tx-M), an index of endogenous thromboxane biosynthesis. Although serum TxB2 was maximally inhibited by 94 +/- 1% after aspirin and 96 +/- 2% after the TxSl, maximal depression of Tx-M was only 28 +/- 8% and 37 +/- 9%, respectively. Combination of aspirin with the TxSl resulted in a small but significant increase in inhibition of thromboxane generation ex vivo (98 +/- 1% v 94 +/- 1%; P less than 0.05), but a disproportionately greater fall in thromboxane synthesis in vivo (58 +/- 7%; P less than 0.01). Consistent with further inhibition of platelet thromboxane synthesis, addition of the TxSl abolished the transient decline in prostacyclin formation after aspirin alone. Administration of a lower dose of aspirin (20 mg) to 6 healthy subjects caused a small reduction in Tx-M (12 +/- 4%; P less than 0.05) and inhibited serum TxB2 by 48 +/- 2%. The relationship between inhibition of platelet capacity to form thromboxane ex vivo (serum TxB2) and synthesis in vivo (Tx-M) departed markedly from the line of identity. When total blockade of the capacity of platelets to generate thromboxane is approached, minor decrements in capacity result in a disproportionate depression of actual thromboxane biosynthesis. These results imply that pharmacologic inhibition of serum TxB2 must be virtually complete before thromboxane- dependent platelet activation is influenced in vivo. 相似文献
105.
Hamilton JA; Whitty GA; Stanton H; Wojta J; Gallichio M; McGrath K; Ianches G 《Blood》1993,82(12):3616-3621
Macrophage colony-stimulating factor (M-CSF or CSF-1) and granulocyte- macrophage CSF (GM-CSF) have been shown to increase human monocyte urokinase-type plasminogen-activator (u-PA) activity with possible consequences for cell migration and tissue remodeling; because monocyte u-PA activity is likely to be controlled in part also by the PA inhibitors (PAIs) made by the cell, the effect of M-CSF and GM-CSF on human monocyte PAI-2 and PAI-1 synthesis was investigated. To this end, elutriation-purified human monocytes were treated in vitro with purified recombinant human M-CSF and GM-CSF, and PAI-2 and PAI-1 antigen and mRNA levels measured by specific enzyme-linked immunosorbent assays and Northern blot, respectively. Each CSF could enhance the protein and mRNA levels of PAI-2 and PAI-1 at similar concentrations for each product. This similar regulation of monocyte PAI expression in response to the CSFs contrasted with that found for the effects of lipopolysaccharide, transforming growth factor-beta and a glucocorticoid. Therefore, PAIs may be modulating the effects of the CSFs on monocyte u-PA activity at sites of inflammation and tissue remodeling. 相似文献
106.
BACKGROUND & AIMS: Microvascular endothelial cells mediate leukocyte homing, angiogenesis, and inflammation and healing and show tissue- specific adhesion molecules and functions. The activation of human intestinal mucosal microvascular endothelial cells (HIMECs) was studied in vitro to uncover possible abnormalities associated with inflammatory bowel disease. METHODS: HIMECs were isolated from normal and inflammatory bowel disease mucosa and assessed for phenotypic and morphological features, proliferative response, leukocyte binding capacity, and adhesion molecule expression. RESULTS: Basal proliferation by HIMECs was less than that of human umbilical vein endothelial cells (HUVECs) but increased proportionally more in response to vascular endothelial growth factor. Proinflammatory stimuli induced an activated, spindle-shaped morphology in HIMEC monolayers. Compared with HUVECs, unstimulated HIMECs showed less adhesiveness for U937 and MOLT4 cells and neutrophils, but cytokines and lipopolysaccharide substantially increased the binding capacity of HIMECs. HIMECs derived from inflammatory bowel disease mucosa showed a markedly greater leukocyte-binding capacity than normal mucosal HIMECs. Patterns of intercellular adhesion molecule 1, vascular cell adhesion molecule 1 and E-selectin messenger RNA expression were distinct in HIMECs, HUVECs, and mucosal mesenchymal cells. CONCLUSIONS: HIMECs represent differentiated endothelial cells with unique functional properties. Their dramatically enhanced capacity to bind leukocytes in inflammatory bowel disease suggests that HIMECs play an important role in initiating or maintaining inflammation. (Gastroenterology 1997 Jun;112(6):1895-907) 相似文献
107.
该研究明确流程优化的相关定义;分析国内外相关研究的现状;研究医院门诊和社区门诊的差异;探讨社区门诊存在或潜在的问题;提出优化社区门诊护理流程的相关策略如:简化流程,规范流程,调整布局,加强信息化建设等,我们致力于建立完善、规范的社区门诊管理体系,形成科学、简洁的社区门诊护理流程。 相似文献
108.
109.
酵母菌药用乳糖酶制备新方法 总被引:3,自引:0,他引:3
目的:建立一种简易的从酵母菌制备克鲁维酵母乳糖酶的方法.方法:在30L发酵罐中进行发酵,用对羟基苯甲酸酯进行细胞破壁,用超微过滤方法浓缩破壁液.结果:乳糖酶的收率可达到每毫升发酵液含11.4 ONPG单位.从酵终细胞中释放乳糖酶可达70%,每毫升牛奶中加入1.2 ONPG单位制备的液态乳糖酶可使牛奶中的乳糖水解率达到70%. 相似文献
110.