全文获取类型
收费全文 | 29298篇 |
免费 | 2681篇 |
国内免费 | 978篇 |
专业分类
耳鼻咽喉 | 370篇 |
儿科学 | 427篇 |
妇产科学 | 888篇 |
基础医学 | 2982篇 |
口腔科学 | 376篇 |
临床医学 | 2876篇 |
内科学 | 3664篇 |
皮肤病学 | 280篇 |
神经病学 | 924篇 |
特种医学 | 1112篇 |
外国民族医学 | 4篇 |
外科学 | 3445篇 |
综合类 | 4863篇 |
预防医学 | 1556篇 |
眼科学 | 189篇 |
药学 | 2240篇 |
13篇 | |
中国医学 | 1314篇 |
肿瘤学 | 5434篇 |
出版年
2024年 | 58篇 |
2023年 | 335篇 |
2022年 | 851篇 |
2021年 | 1136篇 |
2020年 | 1103篇 |
2019年 | 797篇 |
2018年 | 800篇 |
2017年 | 973篇 |
2016年 | 1083篇 |
2015年 | 1082篇 |
2014年 | 2043篇 |
2013年 | 1966篇 |
2012年 | 1945篇 |
2011年 | 2128篇 |
2010年 | 1693篇 |
2009年 | 1604篇 |
2008年 | 1617篇 |
2007年 | 1618篇 |
2006年 | 1411篇 |
2005年 | 1214篇 |
2004年 | 1035篇 |
2003年 | 919篇 |
2002年 | 738篇 |
2001年 | 752篇 |
2000年 | 567篇 |
1999年 | 544篇 |
1998年 | 410篇 |
1997年 | 394篇 |
1996年 | 324篇 |
1995年 | 319篇 |
1994年 | 260篇 |
1993年 | 155篇 |
1992年 | 136篇 |
1991年 | 110篇 |
1990年 | 126篇 |
1989年 | 89篇 |
1988年 | 82篇 |
1987年 | 65篇 |
1986年 | 39篇 |
1985年 | 64篇 |
1984年 | 78篇 |
1983年 | 42篇 |
1982年 | 47篇 |
1981年 | 41篇 |
1980年 | 42篇 |
1979年 | 45篇 |
1978年 | 25篇 |
1977年 | 11篇 |
1976年 | 11篇 |
1973年 | 7篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
171.
Y. Ma S. Ren W. M. Pandak X. Li Y. Ning C. Lu F. Zhao L. Yin 《Inflammation research》2007,56(12):495-501
Objective: To investigate the expression of steroidogenic acute regulatory protein (StAR) in macrophages and the effects of inflammatory
cytokines on StAR expression.
Methods: The macrophages isolated from ApoE knockout mice and C57BL/6J mice and RAW264.7 cells (a cell line from mouse macrophage.
ATCC Number: TIB-71TM) were cultured in DMEM containing 10% fetal bovine serum. RAW264.7 cells were treated with different inflammatory cytokines
(TNF-α, IFN-γ and TGF-β1) and 8-Br-cAMP, a cAMP analog. RT-PCR and Western blot analysis were applied to evaluate the effects
of inflammatory cytokines on StAR expression.
Results: RT-PCR and Western blot analysis demonstrated the expression of StAR in the macrophages isolated from ApoE knockout mice,
C57BL/6J mice and RAW264.7 cells. Proinflammatory cytokines TNF-α and IFN-γ significantly decreased StAR mRNA and protein
levels in RAW264.7 cells. The inhibition was dose- and time-dependent. In contrast, anti-inflammatory cytokine TGF-β1 increased
StAR mRNA and protein levels. At 1:15 molecular ratio, TGF-β1 blocked the down-regulation of StAR expression mediated by TNF-α.
cAMP also induced StAR expression in RAW264.7 cells. When the cells were co-treated with 8-Br-cAMP and TNF-α, 8-Br-cAMP failed
to induce StAR expression.
Conclusion: Our results provide interesting evidence that inflammatory cytokines regulate StAR expression in macrophages.
Received 12 August 2006; returned for revision 28 September 2006; returned for final revision 28 May 2007; accepted by M.
Katori 22 June 2007 相似文献
172.
Adenomatous hyperplasia of the liver is known as a preneoplastic or early developmental stage of hepatocellular carcinoma, in which overt malignant foci occasionally develop. We have recently experienced an autopsy case (a 70-year-old male) of liver cirrhosis with hepatocellular carcinoma and two nodules of adenomatous hyperplasia. The latter two nodules contained several microscopic foci of moderately differentiated hepatocellular carcinoma. There were a number of tumor microemboli in portal vein branches within areas of adenomatous hyperplasia in addition to areas surrounding cirrhotic liver, some of which grew into the parenchyma of adenomatous hyperplasia and cirrhotic regenerative nodules. These findings and the fact that adenomatous hyperplasia contained portal tracts including portal venous branches, suggest that malignant foci in adenomatous hyperplasia of the liver in this case might represent metastases from hepatocellular carcinoma in other parts of the liver via the intrahepatic portal venous system. Acta Pathol Jpn 41: 911 915, 1991. 相似文献
173.
激发型4-1BB单抗联合凋亡肿瘤细胞负载的树突状细胞在恶性肿瘤免疫治疗中的作用 总被引:2,自引:0,他引:2
目的:研究激发型4-1BB单抗(2A)联合凋亡肿瘤细胞负载的DC(AP-DC)疫苗在小鼠B细胞淋巴瘤免疫治疗中的作用.方法:凋亡小鼠B细胞淋巴瘤细胞A20负载的DC用来制备AP-DC.A20荷瘤小鼠分别被注射AP-DC、2A单抗或二者联合.观察肿瘤生长情况及小鼠生存期.流式细胞术检测免疫治疗后荷瘤鼠脾脏T细胞的表型和胞浆内细胞因子;3H-TdR掺入试验检测T细胞体外增殖能力;ELISA法检测荷瘤鼠血清和脾脏T细胞培养上清中IL-2、IFN-γ和IL-10含量.结果:应用激发型4-1BB单抗2A或AP-DC疫苗对荷瘤小鼠开展免疫治疗,可抑制肿瘤生长,延长荷瘤鼠生存期,获得12.5%或25%的肿瘤完全缓解率.但二者联合应用,治疗效果更好,可获得62.5%的肿瘤完全缓解率,并且荷瘤鼠可长期生存.联合治疗后荷瘤鼠脾脏T细胞体外增殖更为显著,CD4^+IFN-γ^+细胞的比例也明显增加.IL-2和IFN-γ的分泌水平在联合治疗荷瘤鼠的血清和脾脏T细胞的培养上清中升高更明显,而IL-10的分泌则降低.结论:激发型4-1BB单抗和AP-DC在肿瘤免疫治疗中有协同作用. 相似文献
174.
利用回旋加速器轰击产生的^11C-C02为合成原料,甲醇化后获得反应活性很强的甲基化前体^11C-CH3I、该前体再与L-高胱氨酸硫内酯在常温下反应,快速制备后获得^11C标记的蛋氨酸(^11C-MET).实验同时对30批次产品进行质量控制指标检测.结果表明从^11C-CH3I到^11C-MET合成时间为2min,合成效率为85%,产品放射化学纯度大于99%;质量控制指标合格。 相似文献
175.
Dr. L. Hens C. Plets R. Dom L. Velghe 《Journal of molecular medicine (Berlin, Germany)》1979,57(14):741-746
Summary A case of endocrinologically active glomus jugulare is presented. The localization within the tumor of the catecholamine hyperproduction was demonstrated by selective venous sampling from the vena jugularis externa draining the tumor.The norepinephrine/epinephrine ratio was high and of the same order in blood, urine and cerebrospinal fluid. Bioassay showed high levels of intratumoral norepinephrine and epinephrine.The ways of treatment and their influence on the catecholamines are briefly discussed. In every phaeochromocytoma-like syndrome both the existence of catecholamine hyperproduction and the anatomical site of this hypersecretion have to be precisely documented in order to define the correct treatment to be applied. 相似文献
176.
Robert F. Todd Stefan C. Meuer Paul L. Romain Stuart F. Schlossman 《Human immunology》1984,10(1):23-40
Previous studies using conventional hetero- or isoantisera have indicated the involvement of class II (Ia) molecules in presentation of soluble by monocytes to inducer T lymphocytes, stimulation of inducer T cells in MLR, and recognition of Ia-bearing targets cells by cytotoxic T lymphocytes (CTL). The experience in using monoclonal anti-Ia reagents capable of blocking these phenomena in the human system is limited. Recently, however, we have characterized a lytic IgG2a monoclonal antibody, 9–49, that binds to functionally significant class II molecules. This antibody blocks (in the absence of complement): (1) specific binding of peripheral blood lymphocytes (PBL) to antigen-pulsed monocyte monolayers, (2) proliferation of PBL in response to soluble antigen (tetanus toxoid or mumps) or cell surface class II antigen stimulation in allogeneic or autologus MLR, (3) proliferation of cloned T4+ (inducer) lymphocyte cell lines to class II antigens, (4) generation of cytotoxic lymphocytes during allogenic MLR, and (5) recognition (and killing) of class II-bearing target cells by T4+ CTL clones. Proliferation and CTL activity of a T8+ clone is unaffected by the 9–49 antibody. These results indicate the usefulness of this monoclonal reagent in studies evaluating the functional role of Ia molecules in immune recognition phenomena. 相似文献
177.
Marion Dorsch Hanno Hock Ulrich Kunzendorf Tibor Diamantstein Thomas Blankenstein 《European journal of immunology》1993,23(1):186-190
In order to analyze the effect of a high local concentration of macrophage colony-stimulating factor (M-CSF; CSF-1) on tumor growth, the plasmacytoma cell line J558L was transfected with the human M-CSF gene and injected into syngeneic BALB/c mice. In contrast to the parental tumors, M-CSF transfectants were heavily infiltrated by macrophages as evidenced by immunohistochemistry with antibodies to Mac-1 and Mac-3 and by isolation of the macrophages from the tumor. Nevertheless, tumor growth was only slightly affected by M-CSF and M-CSF-producing cells grew as tumor in all cases. The growth retardation of M-CSF-producing cells varied depending on the experiment and seemed to be due to an indirect effect because the growth rate of the cells in vitro had not changed upon gene transfer. Attempts to activate the tumor-infiltrating macrophages for tumor suppression by systemic application of interferon-γ and/or lipopolysaccharide were not successful. Altogether, our results suggest that M-CSF is a potent chemoattractant for macrophages in vivo but alone is not sufficient to activate these macrophages for tumoricidal activity. 相似文献
178.
Kazuhiko Orikasa Shin-ichi Fukushige Senji Hoshi Seiichi Orikasa Keiichi Kondo Yasuhide Miyoshi Yoshinobu Kubota A. Horii 《Journal of human genetics》1998,43(4):228-230
Prostate cancer is a major cause of cancer death among elderly men in America, Europe, and Japan. However, the molecular
mechanism of carcinogenesis is not yet well characterized. Frequent loss of heterozygosity (LOH) on chromosome 10q was reported
in prostate cancer, and a candidate tumor suppressor gene, PTEN, was isolated on chromosome band 10q23.3. To investigate the genetic alterations of PTEN, we examined 45 primary prostate cancer specimens. LOH at the PTEN locus was observed in two (11.1%) of 18 tumors. However, no mutations were observed in any of the primary prostate cancers.
These data suggest that mutation of the PTEN gene does not play a major role in prostate carcinogenesis of Japanese patients.
Received: February 6, 1998 / Accepted: July, 3, 1998 相似文献
179.
Kazuhiro Tsukamoto Nobutaka Ohta Yasumasa Shirai M. Emi 《Journal of human genetics》1998,43(4):278-279
Tumor necrosis factor alpha (TNFα) in activated monocytes exerts cytotoxic activity and has a variety of other biological
effects. We isolated a polymorphic dinucleotide (CA) repeat sequence from a genomic clone containing the gene located at 6p21.3.
High heterozygosity (0.80) makes this polymorphism a useful marker in the genetic study of disorders affecting immunological
response and cell differentiation.
Received: June 2, 1998 / Accepted: June 24, 1998 相似文献
180.
Toshishige Suzuki Kennichi Yanagi Keiko Ookawa Katsuyoshi Hatakeyama Norio Ohshima 《Annals of biomedical engineering》1998,26(5):803-811
Dynamic behavior of leukocytes in the microcirculation of solid tumor tissue was visualized using a fluorescent labeling technique combined with the use of a real-time confocal laser-scanning microscope (CLSM) system. Colon tumor cells (RCN-9) were inoculated into the peritoneal cavity of male Fischer 344 rats. Tumor-free rats were similarly injected with physiological saline (intraperitoneally). Ten days after tumor inoculation, the mesentery was exteriorized and subjected to vital microscopic observation under the CLSM system. Leukocytes were labeled with rhodamine 6G (100 g kg–1, intravenously), and their behavior within the microvessels (10–30 m in diameter) was analyzed both in the solid tumor tissues and the normal mesentery. Wall shear rate was calculated from the measured values of vessel diameter and erythrocyte flow velocity. In tumor microvasculature of tumor-bearing rats, the centerline erythrocyte velocity (0.73 ± 0.58 mm s–1, mean±standard deviation) and wall shear rate (210 ± 151 s–1 were significantly lower than those of the tumor-free rats (1.27 ± 0.83 mm s–, 344 ± 236 s–1, respectively). Despite such reduced flow conditions, flux of the rolling leukocytes as well as density of the adhered leukocytes both decreased significantly in tumor microvasculature as compared with normal controls. The methods developed in this work show promise in improving our understanding of tumor biology and pathophysiology. © 1998 Biomedical Engineering Society.
PAC98: 8722Fy, 8745Hw, 8745Ft, 8764-t, 4262Be 相似文献