全文获取类型
收费全文 | 518篇 |
免费 | 28篇 |
国内免费 | 26篇 |
专业分类
儿科学 | 45篇 |
妇产科学 | 8篇 |
基础医学 | 34篇 |
口腔科学 | 28篇 |
临床医学 | 53篇 |
内科学 | 130篇 |
皮肤病学 | 4篇 |
神经病学 | 9篇 |
特种医学 | 116篇 |
外科学 | 27篇 |
综合类 | 4篇 |
预防医学 | 13篇 |
眼科学 | 5篇 |
药学 | 72篇 |
肿瘤学 | 24篇 |
出版年
2022年 | 3篇 |
2021年 | 4篇 |
2020年 | 3篇 |
2019年 | 4篇 |
2018年 | 8篇 |
2017年 | 3篇 |
2016年 | 4篇 |
2015年 | 7篇 |
2014年 | 6篇 |
2013年 | 12篇 |
2012年 | 7篇 |
2011年 | 6篇 |
2010年 | 8篇 |
2009年 | 16篇 |
2008年 | 9篇 |
2007年 | 24篇 |
2006年 | 6篇 |
2005年 | 11篇 |
2004年 | 4篇 |
2003年 | 11篇 |
2002年 | 6篇 |
2001年 | 10篇 |
2000年 | 5篇 |
1999年 | 7篇 |
1998年 | 39篇 |
1997年 | 44篇 |
1996年 | 51篇 |
1995年 | 39篇 |
1994年 | 30篇 |
1993年 | 30篇 |
1992年 | 9篇 |
1991年 | 10篇 |
1990年 | 8篇 |
1989年 | 19篇 |
1988年 | 18篇 |
1987年 | 12篇 |
1986年 | 10篇 |
1985年 | 11篇 |
1984年 | 9篇 |
1983年 | 5篇 |
1982年 | 7篇 |
1981年 | 5篇 |
1980年 | 5篇 |
1979年 | 4篇 |
1978年 | 2篇 |
1977年 | 6篇 |
1976年 | 6篇 |
1975年 | 8篇 |
1954年 | 1篇 |
排序方式: 共有572条查询结果,搜索用时 390 毫秒
61.
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
62.
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
63.
64.
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
65.
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66.
67.
68.
69.
70.
CD40 ligand triggered interleukin-6 secretion in multiple myeloma 总被引:11,自引:3,他引:8
Previous studies have suggested that interleukin-6 (IL-6) may mediate growth of multiple myeloma (MM) in either an autocrine or paracrine growth mechanism. However, those molecules which can trigger IL-6 secretion either by tumor cells or non-MM marrow cells are not well characterized. In the present study, we have examined the expression and functional significance of CD40 on MM and plasma cell leukemia (PCL) cells and derived cell lines, as well as long-term bone marrow stromal cells (BMSCs) and derived cell lines. CD40 was expressed on the majority of MM cells (> 90%) and BMSCs (> 70%). Triggering via CD40 using NIH3T3 CD40 ligand transfectant (CD40LT) cells increased (> 30%) cell surface CD80, CD18, CD11a, CD11b, and CD11c expression on MM cell lines. Culture with either fresh or paraformaldehyde fixed NIH3T3 CD40LT cells upregulates IL-6 secretion in MM cells and MM-derived cell lines, as well as normal and MM bone marrow mononuclear cells (BMMCs), BMSCs, and BMSC lines; this effect can be specifically blocked by anti- CD40 monoclonal antibody (MoAb). BMMCs and BMSCs from patients with MM secreted significantly more IL-6 than those from healthy donors (n = 3, P < .001); moreover, after stimulation using CD40L, IL-6 secretion was fourfold greater (n = 3, P < .001) from MM BMMCs and BMSCs than from normal BMMCs and BMSCs. Myeloma (CD38+CD45RA-) cells and non-MM (CD38+CD45RA+, CD38-CD45RA+, and CD38-CD45RA-) BMMCs were separated by dual fluorescence cell sorting. The latter secreted fourfold more IL-6 than the former (n = 2, P < .001). Increased IL-6 secretion (up to 28- fold) and proliferation (Stimulation index 10) by CD38+CD45RA-MM cells was triggered by culture with NIH3T3 CD40LT cells. Finally, anti- CD40MoAb partially (30%) blocked tumor cell to BMSC adhesion-induced IL- 6 secretion. These studies support the view that CD40L may trigger IL-6 secretion by both MM cells and BMSCs and that IL-6-mediated autocrine and paracrine growth mechanisms may be possible in MM. 相似文献