全文获取类型
收费全文 | 499篇 |
免费 | 16篇 |
国内免费 | 21篇 |
专业分类
耳鼻咽喉 | 1篇 |
儿科学 | 24篇 |
妇产科学 | 5篇 |
基础医学 | 48篇 |
口腔科学 | 30篇 |
临床医学 | 31篇 |
内科学 | 93篇 |
皮肤病学 | 13篇 |
神经病学 | 8篇 |
特种医学 | 95篇 |
外科学 | 55篇 |
综合类 | 50篇 |
预防医学 | 21篇 |
眼科学 | 6篇 |
药学 | 41篇 |
肿瘤学 | 15篇 |
出版年
2022年 | 4篇 |
2021年 | 2篇 |
2020年 | 2篇 |
2019年 | 3篇 |
2018年 | 8篇 |
2017年 | 4篇 |
2016年 | 2篇 |
2015年 | 9篇 |
2014年 | 8篇 |
2013年 | 18篇 |
2012年 | 4篇 |
2011年 | 11篇 |
2010年 | 23篇 |
2009年 | 24篇 |
2008年 | 6篇 |
2007年 | 28篇 |
2006年 | 28篇 |
2005年 | 9篇 |
2004年 | 20篇 |
2003年 | 11篇 |
2002年 | 8篇 |
2001年 | 8篇 |
2000年 | 7篇 |
1999年 | 6篇 |
1998年 | 27篇 |
1997年 | 31篇 |
1996年 | 38篇 |
1995年 | 21篇 |
1994年 | 12篇 |
1993年 | 20篇 |
1992年 | 6篇 |
1991年 | 4篇 |
1990年 | 2篇 |
1989年 | 21篇 |
1988年 | 10篇 |
1987年 | 13篇 |
1986年 | 10篇 |
1985年 | 10篇 |
1984年 | 9篇 |
1983年 | 5篇 |
1982年 | 5篇 |
1981年 | 5篇 |
1980年 | 10篇 |
1979年 | 3篇 |
1978年 | 3篇 |
1977年 | 5篇 |
1976年 | 5篇 |
1975年 | 5篇 |
1962年 | 1篇 |
1935年 | 1篇 |
排序方式: 共有536条查询结果,搜索用时 15 毫秒
531.
EM Varga MR Jacobson SJ Till K Masuyama F O''Brien SR Durham S Rak V Lund GK Scadding QA Hamid 《Allergy》1999,54(4):338-345
BACKGROUND: Allergen challenge in allergic rhinitis patients leads to local eosinophilia and Th2-type cytokine expression. Natural exposure to grass pollen is additionally characterized by epithelial mast-cell infiltration. We hypothesized that perennial allergic rhinitis is also associated with T-cell and eosinophil infiltration of the nasal mucosa, local Th2-type cytokine expression, and increased numbers of nasal epithelial mast cells. METHODS: Nasal biopsies from perennial allergic rhinitis patients and controls were analysed by immunocytochemistry for different cell populations and in situ hybridization for cytokine mRNA-expressing cells. RESULTS: Perennial allergic rhinitis was associated with increased numbers of submucosal CD3+ T cells (P=0.05), EG2+ activated eosinophils (P=0.01), and CD68+ macrophages (P=0.01) compared to controls. Epithelial, but not submucosal, tryptase-positive mast cells were also elevated in rhinitics compared to controls (P=0.01). The numbers of cells expressing interleukin (IL)-5 were higher (P=0.01) and the numbers of cells expressing IL-2 were lower (P=0.04) in rhinitic patients than controls. There were no significant differences for either IL-4 or interferon-gamma between the groups. CONCLUSIONS: Perennial allergic rhinitis is characterized by mast-cell migration into the epithelium; submucosal infiltration by T cells, eosinophils, and macrophages; and an imbalance in local T-cell cytokine production in favour of enhanced IL-5 and reduced IL-2 expression. 相似文献
532.
消旋(15R)-15甲基PGE2甲酯(PG6E)对大鼠实验性胃溃疡的保护作用 总被引:2,自引:0,他引:2
用实验性胃溃疡模型研究了PG6E的抗溃疡作用,结果表明PG6E有抗胃酸分泌作用,而对胃肠运动无明显影响;PG6E在剂量为10~80μg·kg-1时,对无水乙醇型、盐酸型、消炎痛型、慢性醋酸型和幽门结扎型胃溃疡有明显保护作用,并能显著减少幽门结扎大鼠的胃液体积、胃酸分泌、胃蛋白酶活性和DNA含量。小鼠poPG6E30~60μg·kg-1,3d后粘膜氨基己糖含量显著增加。研究结果提示PG6E能抑制对胃粘膜的攻击性因素,增加保护性因素的作用,可望成为一种新型抗胃溃疡药。 相似文献
533.
Platelet kinetics in patients with bone marrow hypoplasia: evidence for a fixed platelet requirement 总被引:6,自引:4,他引:6
We have studied 16 normal subjects and 27 patients with stable, untreated thrombocytopenia secondary to bone marrow failure and platelet counts ranging from 12,000 to 70,000/microL. Autologous platelets were labeled with 51Cr for measurement of mean platelet life span in the normal subjects and in 20 patients. Labeled donor cells were used in the remaining subjects. Platelet survival, as determined with both autologous and homologous platelets, correlated directly with platelet count in the thrombocytopenic patients. Platelet life span was only modestly reduced in patients having counts in the range of 50,000 to 100,000/microL (7.0 +/- 1.5 days v 9.6 +/- 0.6; P less than .01) but was markedly reduced when the count fell below 50,000/microL (5.1 +/- 1.9 days, P less than .001). The recovery of donor platelets in severely thrombocytopenic recipients (60% +/- 15%) was equivalent to control values (66% +/- 8%; P greater than .2). The recovery of autologous platelets was normal when the platelet count exceeded 50,000/microL (74% +/- 15%) but was reduced in patients with lower counts (50% +/- 22%; P less than .01). All patient and normal data were well correlated by a model predicting a maximum platelet life span of 10 1/2 days and a fixed requirement for 7,100 platelets per microliter of blood per day, or about 18% of the normal rate of platelet turnover, which averaged 41,200 platelets per microliter per day. We conclude that although relatively few platelets are used to support vascular integrity, this requirement is reflected by a reduced platelet life span in marrow hypoplasia and may contribute to the shortening of platelet survival observed in other thrombocytopenias. 相似文献
534.
535.
536.