全文获取类型
收费全文 | 799篇 |
免费 | 36篇 |
国内免费 | 27篇 |
专业分类
儿科学 | 53篇 |
妇产科学 | 10篇 |
基础医学 | 62篇 |
口腔科学 | 24篇 |
临床医学 | 113篇 |
内科学 | 235篇 |
皮肤病学 | 6篇 |
神经病学 | 16篇 |
特种医学 | 125篇 |
外科学 | 66篇 |
综合类 | 4篇 |
预防医学 | 31篇 |
眼科学 | 6篇 |
药学 | 85篇 |
肿瘤学 | 26篇 |
出版年
2022年 | 4篇 |
2021年 | 9篇 |
2020年 | 5篇 |
2019年 | 6篇 |
2018年 | 6篇 |
2017年 | 6篇 |
2016年 | 5篇 |
2015年 | 9篇 |
2014年 | 8篇 |
2013年 | 22篇 |
2012年 | 24篇 |
2011年 | 9篇 |
2010年 | 13篇 |
2009年 | 23篇 |
2008年 | 17篇 |
2007年 | 35篇 |
2006年 | 22篇 |
2005年 | 24篇 |
2004年 | 13篇 |
2003年 | 17篇 |
2002年 | 19篇 |
2001年 | 17篇 |
2000年 | 16篇 |
1999年 | 20篇 |
1998年 | 49篇 |
1997年 | 47篇 |
1996年 | 56篇 |
1995年 | 42篇 |
1994年 | 37篇 |
1993年 | 33篇 |
1992年 | 19篇 |
1991年 | 13篇 |
1990年 | 19篇 |
1989年 | 27篇 |
1988年 | 23篇 |
1987年 | 27篇 |
1986年 | 17篇 |
1985年 | 17篇 |
1984年 | 21篇 |
1983年 | 13篇 |
1982年 | 8篇 |
1981年 | 6篇 |
1980年 | 5篇 |
1979年 | 5篇 |
1978年 | 2篇 |
1977年 | 7篇 |
1976年 | 7篇 |
1975年 | 8篇 |
1972年 | 2篇 |
1904年 | 1篇 |
排序方式: 共有862条查询结果,搜索用时 15 毫秒
91.
Transient leukemoid proliferation of the cytogenetically unbalanced +21 cell line of a constitutional mosaic boy 总被引:1,自引:0,他引:1
A newborn without any signs of Down's syndrome was found to have an acute proliferation that remitted without drug therapy. Chromosomal analysis of blood, bone marrow, and skin cells revealed that the child was a constitutional mosaic with normal cells and a low number of cells in which one no. 21 chromosome was replaced by a probably isochromosome for the no. 21 long arm: 46,XY/46,XY,i(21q). The abnormal cell line of the mosaic appeared to be selectively involved in this proliferation. 相似文献
92.
D'Andrea RJ; Barry SC; Moretti PA; Jones K; Ellis S; Vadas MA; Goodall GJ 《Blood》1996,87(7):2641-2648
The hypothesis that extracellular truncation of the common receptor subunit for interleukin-3 (IL-3), granulocyte-macrophage colony- stimulating factor, and IL-5 (h beta c) can lead to ligand-independent activation was tested by infecting factor-dependent hematopoietic cell lines with retroviruses encoding truncated forms of h beta c. A truncation, resembling that in v-Mpl, and retaining 45 h beta c-derived extracellular residues, led to constitutive activation in the murine myeloid cell line, FDC-P1. However, infection of cells with retrovirus encoding a more severely truncated receptor, retaining only 7 h beta c- derived extracellular residues, did not confer factor independence on these cells. These experiments show that truncation activates the receptor and define a 37-amino acid segment of h beta c (H395-A431) which contains two motifs conserved throughout the cytokine receptor superfamily (consensus Y/H XX R/Q VR and WSXWS), as essential for factor-independent signaling. The mechanism of activation was also investigated in less severe truncations. A receptor that retains the entire membrane-proximal domain (domain 4) also conferred factor independent growth on FDC-P1 cells; however, a retrovirus encoding a truncated form of h beta c having two intact membrane proximal domains did not have this ability, suggesting that domain 3 may have an inhibitory role in h beta c. The ability of these receptors to confer factor independence was cell specific as demonstrated by their inability to confer factor-independent growth when introduced into the murine IL-3-dependent pro-B cell line BaF-B03. These results are consistent with a model in which activation requires unmasking of an interactive receptor surface in domain 4 and association with a myeloid- specific receptor or accessory component. We suggest that in the absence of ligand intramolecular interactions prevent inappropriate signaling. 相似文献
93.
94.
Kersti Bruining Kenneth Weiss Barbara Zeifer Christopher Comfort Jerry G. Kaplan 《Journal of neuroimaging》1993,3(1):55-57
A patient with cauda equina syndrome from long-standing ankylosing spondylitis exhibited erosive cystic defects of the thecal sac on lumbosacral magnetic resonance imaging. This report confirms the presence of nerve root clumping described previously, documents contrast enhancement of the leptomeninges for the first time, and suggests that arachnoiditis has a role in the evolution of this disorder. 相似文献
95.
注射用双黄连与几种抗生素联合体外抑菌活性的研究 总被引:11,自引:0,他引:11
目的:探讨注射用双黄连与抗生素联合使用的临床意义。方法:参考中国药典抗生素微生物检定法,测定注射用双黄连与头孢拉定等6种抗生素配伍使用后对金葡菌及克雷白氏肺炎杆菌的抑菌圈直径的变化。结果:注射用双黄连与氨苄青霉素、普鲁卡因青霉素、头孢唑啉钠及红霉素配伍后对金葡萄的体外抑菌效果明显增强;与头孢拉定、头孢唑啉钠及普鲁卡因青霉素配伍后对克氏肺炎杆菌的体外抑菌效果有不同程度的增强。结论:对于不同的细菌感染 相似文献
96.
Marleen Vree Nguyen T Huong Bui D Duong Dinh N Sy Le N Van Nguyen V Co Frank GJ Cobelens Martien W Borgdorff 《BMC public health》2007,7(1):134
Background
Tuberculosis treatment failure and death rates are low in the Western Pacific Region, including Vietnam. However, failure or death may also occur among patients who did not complete treatment, i.e. reported as default or transfer-out. We aimed to assess the proportion failures and deaths among new smear-positive pulmonary tuberculosis patients with reported default or transfer-out. 相似文献97.
98.
99.
100.