全文获取类型
收费全文 | 104847篇 |
免费 | 8734篇 |
国内免费 | 6171篇 |
专业分类
耳鼻咽喉 | 1113篇 |
儿科学 | 1547篇 |
妇产科学 | 2305篇 |
基础医学 | 12444篇 |
口腔科学 | 1955篇 |
临床医学 | 14047篇 |
内科学 | 16602篇 |
皮肤病学 | 897篇 |
神经病学 | 5676篇 |
特种医学 | 3547篇 |
外国民族医学 | 42篇 |
外科学 | 11251篇 |
综合类 | 14822篇 |
现状与发展 | 23篇 |
一般理论 | 20篇 |
预防医学 | 6123篇 |
眼科学 | 2867篇 |
药学 | 10754篇 |
56篇 | |
中国医学 | 4838篇 |
肿瘤学 | 8823篇 |
出版年
2024年 | 280篇 |
2023年 | 1504篇 |
2022年 | 3803篇 |
2021年 | 4974篇 |
2020年 | 3521篇 |
2019年 | 3241篇 |
2018年 | 3545篇 |
2017年 | 2926篇 |
2016年 | 2846篇 |
2015年 | 4418篇 |
2014年 | 5626篇 |
2013年 | 5012篇 |
2012年 | 7526篇 |
2011年 | 8268篇 |
2010年 | 4989篇 |
2009年 | 3827篇 |
2008年 | 5274篇 |
2007年 | 5556篇 |
2006年 | 5418篇 |
2005年 | 5711篇 |
2004年 | 3834篇 |
2003年 | 3401篇 |
2002年 | 3008篇 |
2001年 | 2445篇 |
2000年 | 2653篇 |
1999年 | 2705篇 |
1998年 | 1594篇 |
1997年 | 1501篇 |
1996年 | 1316篇 |
1995年 | 1169篇 |
1994年 | 992篇 |
1993年 | 645篇 |
1992年 | 1002篇 |
1991年 | 811篇 |
1990年 | 687篇 |
1989年 | 605篇 |
1988年 | 598篇 |
1987年 | 530篇 |
1986年 | 422篇 |
1985年 | 331篇 |
1984年 | 208篇 |
1983年 | 160篇 |
1982年 | 85篇 |
1981年 | 98篇 |
1980年 | 83篇 |
1979年 | 115篇 |
1978年 | 54篇 |
1977年 | 56篇 |
1976年 | 48篇 |
1974年 | 45篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
151.
H M Vijay G Lavergne H Huang I L Bernstein 《International archives of allergy and applied immunology》1979,59(2):227-232
The reaginic antibody response to alum-precipitated ovalbumin (OA) and the dialyzed water-soluble extracts of ragweed (DWSR) and Alternaria tenuis (DWST) in several strains of rats appeared to be wholly an IgE response. There was no evidence of a heat-stable (IgGa) antibody to OA, DWSR and DWST in the sera of the rats immunized with these antigens suspended in alum. Wistar-Furth and Lew inbred and hooded outbred rats produced comparable amounts of reaginic antibody after immunization with DWST, but BN inbred rats failed to generate a reaginic response to this antigen. The amount of antigen-induced histamine release from rat peritoneal mast cells did not always correlate with the level of circulating IgE-specific antibody. 相似文献
152.
153.
Effects of omalizumab and budesonide on markers of inflammation in human bronchial epithelial cells.
Yu-Ching Huang Bartlomiej Leyko Marianne Frieri 《Annals of allergy, asthma & immunology》2005,95(5):443-451
BACKGROUND: Many patients with asthma have an IgE-mediated allergic component to the disease. Omalizumab, a monoclonal anti-IgE antibody, has demonstrated clinical efficacy in patients with allergic asthma. The effects of omalizumab on inflammation in asthma are not completely understood. OBJECTIVES: To evaluate the effects of omalizumab on allergen- and growth factor-stimulated proinflammatory cytokine and nitric oxide (NO) production in human bronchial epithelial cells (BECs) and to compare them to the effects of budesonide, a corticosteroid with known anti-inflammatory properties. METHODS: Human BECs were stimulated in duplicate with interleukin 1beta (IL-1beta), 100 U/mL; ragweed, 10 microg/mL; dust mite, 1000 AU; and epithelial growth factor, 40 ng/mL; and either 10(-7) M budesonide or 0.1 microg/mL of omalizumab in a 4% dust mite atopic serum medium for 6 and 24 hours in 5% carbon dioxide at 37 degrees C. Tumor necrosis factor alpha and transforming growth factor betaexpression and production and IL-4, IL-13, and NO production were assayed using gene-specific messenger RNA or sensitive enzyme-linked immunosorbent assays. RESULTS: Omalizumab inhibited the expression and of production proinflammatory cytokines and growth factor in antigen-stimulated BECs at 6 and 24 hours. Production of NO was inhibited at 6 hours and increased at 24 hours by omalizumab and budesonide. CONCLUSIONS: The effects of omalizumab were similar to those of budesonide. These results, consistent with previously reported evidence of anti-inflammatory effects of omalizumab, demonstrate that omalizumab may reduce airway inflammation and probably contributes to decreased airway remodeling in patients with asthma. 相似文献
154.
155.
The extracellular matrix of pulmonary scar carcinomas is suggestive of a desmoplastic origin. 总被引:2,自引:1,他引:2 下载免费PDF全文
Pulmonary scar carcinomas and noncarcinomatous apical scars were subjected to collagen extraction, ultrastructural, and immunocytochemical studies designed to investigate the nature of their extracellular matrix. These studies revealed marked differences in both cellular and biochemical composition of scar carcinomas, compared with apical scars. Myofibroblasts, identified by antimyosin antibodies and confirmed by electron microscopy, constituted over 90% of the stromal cells of the scar carcinomas, compared with 0-10% in the apical scars. Collagen extraction studies revealed both an absolute and relative increase in Type V collagen in the scar carcinomas, compared with that found in the apical scars. The extracellular matrix of the pulmonary scar carcinomas was, however, identical to that of scirrhous carcinomas of the breast. These findings suggest that pulmonary scar carcinomas are probably desmoplastic carcinomas, rather than scar-arising tumors. 相似文献
156.
培养细胞整装内质网三维结构的多态性 总被引:3,自引:0,他引:3
用高锰酸钾-锇酸固定法制备了5种培养细胞整装内质网标本,并在扫描电镜下对其三维结构进行了观察。观察结果表明内质网是由膜性小管构成的贯穿整个细胞质的管囊网络样膜性区室,并以多种形态深入到细胞伪足及突起中;细胞质中内质网则表现为簇状网络(见于GCM3T3细胞)、多态性多孔扁囊样网络、筛网状网络、条索状网络、大孔条索网状和细孔扁囊样分区网络、不规则管网状和多孔管囊分区网络(见于CV-1细胞)、细管网络(见于CCL187和CCL229细胞)、球囊网络(见于CCL187和A431细胞)和不规则管网状网络(见于A431细胞)等。内质网的这种多态性提示它是一种高度可变的结构,其可变性可能与细胞特性、分化程度、细胞功能状态及细胞骨架系统的分布变化等因素有关。 相似文献
157.
158.
159.
人FascDNA的克隆及其在大肠杆菌中表达的研究 总被引:1,自引:1,他引:1
为获得高质量及充足的Fas蛋白,采用PCR技术调整Fas基因的开放阅读框架,使之与生物素化蛋白基因阅读框架一致;缺失了FascDNA基因的起始密码子并增加一个大肠杆菌偏性终止密码子,构建FascDNA和生物素化融合原核表达质粒PinPoint-Fas。将重组质粒转入大肠杆菌HB101,经500mmolIPTG在37℃条件下诱导4h,SDS-PAGE及Western印迹检测融合蛋白在大肠杆菌得以高效表达,表达量为细菌总蛋白的13.8%。用亲和层析树脂对生物素化融合蛋白进行亲和层析纯化,得到Fas重组的蛋白,且表达的Fas融合蛋白具有抗体结合活性。此蛋白的表达成功将解决Fas膜蛋白不易提取的难题,为深入研究Fas提供了良好材料来源 相似文献
160.
The muntjacs (Muntiacus, Cervidae) are famous for their rapid and radical karyotypic diversification via repeated tandem chromosome fusions, constituting
a paradigm for the studies of karyotypic evolution. Of the five muntjac species with defined karyotypes, three species (i.e.
Muntiacus reevesi, 2n = 46; M. m. vaginalis, 2n = 6/7; and M. crinifrons, 2n = 8/9) have so far been investigated by a combined approach of comparative chromosome banding, chromosome painting and
BAC mapping. The results demonstrated that extensive centromere–telomere fusions and a few centric fusions are the chromosomal
mechanisms underlying the karyotypic evolution of muntjacs. Here we have applied the same approach to two additional muntjac
species with less well-characterized karyotypes, M. feae (2n = 14♂) and M. gongshanensis (2n = 8♀). High-resolution G-banded karyotypes for M. feae and M. gongshanensis are provided. The integrated analysis of hybridization results led to the establishment of a high-resolution comparative
map between M. reevesi, M. feae, and M. gongshanensis, proving that all tandem fusions underpinning the karyotypic evolution of these two muntjac species are also centromere–telomere
fusions. Furthermore, the results have improved our understanding of the karyotypic relationships of extant muntjac species
and provided compelling cytogenetic evidence that supports the view that M. crinifrons, M. feae, and M. gongshanensis should each be treated as a distinct species. 相似文献