全文获取类型
收费全文 | 3680篇 |
免费 | 230篇 |
国内免费 | 109篇 |
出版年
2024年 | 7篇 |
2023年 | 45篇 |
2022年 | 34篇 |
2021年 | 92篇 |
2020年 | 99篇 |
2019年 | 99篇 |
2018年 | 118篇 |
2017年 | 69篇 |
2016年 | 94篇 |
2015年 | 101篇 |
2014年 | 185篇 |
2013年 | 380篇 |
2012年 | 124篇 |
2011年 | 175篇 |
2010年 | 134篇 |
2009年 | 182篇 |
2008年 | 188篇 |
2007年 | 208篇 |
2006年 | 178篇 |
2005年 | 151篇 |
2004年 | 158篇 |
2003年 | 158篇 |
2002年 | 116篇 |
2001年 | 107篇 |
2000年 | 105篇 |
1999年 | 106篇 |
1998年 | 89篇 |
1997年 | 64篇 |
1996年 | 64篇 |
1995年 | 66篇 |
1994年 | 57篇 |
1993年 | 37篇 |
1992年 | 23篇 |
1991年 | 19篇 |
1990年 | 18篇 |
1989年 | 19篇 |
1988年 | 19篇 |
1987年 | 13篇 |
1986年 | 13篇 |
1985年 | 23篇 |
1984年 | 19篇 |
1983年 | 7篇 |
1982年 | 18篇 |
1981年 | 14篇 |
1980年 | 4篇 |
1979年 | 10篇 |
1978年 | 3篇 |
1977年 | 2篇 |
1976年 | 2篇 |
1973年 | 1篇 |
排序方式: 共有4019条查询结果,搜索用时 859 毫秒
91.
Rui-Zan Shi Yi-Fan He Jie Wen Ya-Nan Niu Yu Gao Lin-Hong Liu Xuan-Ping Zhang Yan Wang Xiu-Li Zhang Hui-Feng Zhang Min Chen Xiao-ling Hu 《Cell biology international》2021,45(8):1644-1653
Overexpression of breast cancer resistance protein (BCRP) plays a crucial role in the acquired multidrug resistance (MDR) in breast cancer. The elucidation of molecular events that confer BCRP-mediated MDR is of major therapeutic importance in breast cancer. Epithelial cell adhesion molecule (EpCAM) has been implicated in tumor progression and drug resistance in various types of cancers, including breast cancer. However, the role of EpCAM in BCRP-mediated MDR in breast cancer remains unknown. In the present study, we revealed that EpCAM expression was upregulated in BCRP-overexpressing breast cancer MCF-7/MX cells, and EpCAM knockdown using siRNA reduced BCRP expression and increased the sensitivity of MCF-7/MX cells to mitoxantrone (MX). The epithelial–mesenchymal transition (EMT) promoted BCRP-mediated MDR in breast cancer cells, and EpCAM knockdown partially suppressed EMT progression in MCF-7/MX cells. In addition, Wnt/β-catenin signaling was activated in MCF-7/MX cells, and the inhibition of this signaling attenuated EpCAM and BCRP expression and partially reversed EMT. Together, this study illustrates that EpCAM upregulation by Wnt/β-catenin signaling induces partial EMT to promote BCRP-mediated MDR resistance in breast cancer cells. EpCAM may be a potential therapeutic target for overcoming BCRP-mediated resistance in human breast cancer. 相似文献
92.
E. Walker S.M. Turaga X. Wang R. Gopalakrishnan S. Shukla J.P. Basilion J.D. Lathia 《Translational oncology》2021,14(3):101007
IntroductionProstate and breast cancer are the most prevalent primary malignant human tumors globally. Prostatectomy and breast conservative surgery remain the most common definitive treatment option for the >500,000 men and women newly diagnosed with localized prostate and breast cancer each year only in the US. Morphological examination is the mainstay of diagnosis but margin under-sampling of the excised cancer tissue may lead to local recurrence. In despite of the progress of non-invasive optical imaging, there is still a clinical need for targeted optical imaging probes that could rapidly and globally visualize cancerous tissues.MethodsElevated expression of junctional adhesion molecule-A (JAM-A) on tumor cells and its multiple pro-tumorigenic activity make the JAM-A a candidate for molecular imaging. Near-infrared imaging probe, which employed anti-JAM-A monoclonal antibody (mAb) phthalocyanine dye IR700 conjugates (JAM-A mAb/IR700), was synthesized and used to identify and visualize heterotopic human prostate and breast tumor mouse xenografts in vivo.ResultsThe intravenously injected JAM-A mAb/IR700 conjugates enabled the non-invasive detection of prostate and breast cancerous tissue by fluorescence imaging. A single dose of JAM-A mAb/IR700 reduced number of mitotic cancer cells in vivo, indicating theranostic ability of this imaging agent. The JAM-A mAb/IR700 conjugates allowed us to image a specific receptor expression in prostate and breast tumors without post-image processing.ConclusionThis agent demonstrates promise as a method to image the extent of prostate and breast cancer in vivo and could assist with real-time visualization of extracapsular extension of cancerous tissue. 相似文献
93.
Kanako Fukunaga Masafumi Tanji Nana Hanzawa Hiroki Kuroda Masafumi Inui 《Biochemistry and Biophysics Reports》2021
Notochord is an embryonic midline structure that serves as mechanical support for axis elongation and the signaling center for the surrounding tissues. Precursors of notochord are initially induced in the dorsal most mesoderm region in gastrulating embryo and separate from the surrounding mesoderm/endoderm tissue to form an elongated rod-like structure, suggesting that cell adhesion molecules may play an important role in this step. In Xenopus embryo, axial protocadherin (AXPC), an orthologue of mammalian Protocadherin-1 (PCDH1), is indispensable for the assembly and separation from the surrounding tissue of the notochord cells. However, the role of PCDH1 in mammalian notochord remains unknown. We herein report that PCDH1 is expressed in the notochord of mouse embryo and that PCDH1-deficient mice form notochord normally. First, we examined the temporal expression pattern of pcdh1 and found that pcdh1 mRNA was expressed from embryonic day (E) 7.5, prior to the stage when notochord cells detach from the surrounding endoderm tissue. Second, we found that PCDH1 protein is expressed in the notochord of mouse embryos in addition to the previously reported expression in endothelial cells. To further investigate the role of PCDH1 in embryonic development, we generated PCDH1-deficient mice using the CRISPR-Cas9 system. In PCDH1-deficient embryos, notochord formation and separation from the surrounding tissue were normal. Structure and marker gene expression of notochord were also unaffected by loss of PCDH1. Major vascular patterns in PCDH1-deficient embryo were essentially normal. These results suggest that PCDH1 is dispensable for notochord formation, including the tissue separation process, in mammalian embryos. We successfully identified the evolutionary conserved expression of PCDH1 in notochord, but its function may differ among species. 相似文献
94.
Jaykrishna Singh Fazle Hussain 《Computer methods in biomechanics and biomedical engineering》2013,16(3):282-292
Cell–cell and cell–matrix adhesions are fundamental to numerous physiological processes, including angiogenesis, tumourigenesis, metastatic spreading and wound healing. We use cellular potts model to computationally predict the organisation of cells within a 3D matrix. The energy potentials regulating cell–cell (JCC) and cell–matrix (JMC) adhesive interactions are systematically varied to represent different, biologically relevant adhesive conditions. Chemotactically induced cell migration is also addressed. Starting from a cluster of cells, variations in relative cell adhesion alone lead to different cellular patterns such as spreading of metastatic tumours and angiogenesis. The combination of low cell–cell adhesion (high JCC) and high heterotypic adhesion (low JMC) favours the fragmentation of the original cluster into multiple, smaller cell clusters (metastasis). Conversely, cellular systems exhibiting high-homotypic affinity (low JCC) preserve their original configuration, avoiding fragmentation (organogenesis). For intermediate values of JCC and JMC (i.e. JCC/JMC ~ 1), tubular and corrugated structures form. Fully developed vascular trees are assembled only in systems in which contact-inhibited chemotaxis is activated upon cell contact. Also, the rate of secretion, diffusion and sequestration of chemotactic factors, cell deformability and motility do not significantly affect these trends. Further developments of this computational model will predict the efficacy of therapeutic interventions to modulate the diseased microenvironment by directly altering cell cohesion. 相似文献
95.
96.
Foudil Lamari Nushjira Pongnimitprasert Maguy Bernard Marie-Jose Foglietti Christian Derappe 《Free radical research》2013,47(7):812-822
The effects of oxidative stress on integrin-mediated cell adhesion to the extracellular matrix (ECM) and related apoptosis were investigated using the EA.hy926 endothelial cells treated (or not) with two oxidants: the hypoxanthine/xanthine oxidase system (HX/XO) or the tert-butyl hydroperoxide (t-BHP) which both increased cell apoptosis. Cell adhesion onto vitronectin (Vn) and fibronectin (Fn) was increased at low concentrations of HX/XO (up to 5 mU/ml) or t-BHP (up to 125 μM) and prevented ROS-induced apoptosis. Flow cytometry analysis of integrin expression showed that the expression of integrin αv and α5 subunits was, respectively, increased and decreased. Cell adhesion inhibition experiments using function-blocking monoclonal antibodies against integrin subunits indicated that αvβ1 and αvβ3 integrins were involved in adhesion of cells to Vn, and αvβ3 integrin played a major role in oxidant-treated cells. For adhesion to Fn, α5β1 and αvβ1 integrins were required for oxidant-treated cells. Taken together, the results suggest that reactive oxygen species (ROS) produced either by HX/XO or t-BHP could affect expression and/or activation of specific integrins in the interaction of EA.hy926 cells with ECM. 相似文献
97.
Chuying Ma Guangfu Yin Danhong Yan Xueling He Li Zhang Yan Wei Zhongbing Huang 《Journal of peptide science》2013,19(12):730-736
Discovery of peptide ligands that can target human ovarian cancer and deliver chemotherapeutics offers new opportunity for cancer therapy. The advent of phage‐displayed peptide library facilitated the screening of such peptides. In vivo screening that set in a microanatomic and functional context was applied in our study, and a novel peptide WSGPGVWGASVK targeting ovarian cancer was isolated. The phage clone PC3‐1 displaying peptide WSGPGVWGASVK can gain effective access to accumulate in the tumor sites after intravenous injection while reducing its accumulation in normal organs. Positive immunostaining of PC3‐1 was located in both sites of tumor cells and tumor blood vessels, which resulted in a diffuse binding pattern through the tumor. In vitro study results confirmed the capability of peptide WSGPGVWGASVK binding to and being internalized by both tumor cells and angiogenic endothelial cells. Flow cytometry analysis revealed that the peptide bound to SKOV3 cells with Kd value of 5.43 ± 0.4 μM. Taken together, it suggested that peptide WSGPGVWGASVK is a lead candidate for delivering therapeutics to penetrate into tumors. Copyright © 2013 European Peptide Society and John Wiley & Sons, Ltd. 相似文献
98.
《Journal of receptor and signal transduction research》2013,33(4):340-345
AbstractHigh-mobility group box-1 protein (HMGB1) is a highly conserved non-histone DNA-binding protein present in the nuclei and cytoplasm of nearly all cell types. The results from recent research provide evidence that HMGB1 is secreted into the extracellular milieu and acts as a pro-inflammatory cytokine and exhibits angiogenic effects to fire the immunological response against the pathological effects. Recently, a great deal of evidence has indicated the critical importance of HMGB1 in mediating vascular barriers dysfunction by modulating the expression of adhesion molecules, such as intercellular adhesion molecule-1, vascular cell adhesion protein 1 and E-selectin on the surface of endothelial cells. Such process promotes the adhesion and migration of leukocytes across the endothelium, leading to breakdown of vascular barriers (blood–brain barrier and blood–retinal barrier) via modulating the expression, content, phosphorylation, and distribution of tight junction proteins. Therefore, here we give an abridged review to understand the mechanistic link between HMGB1 and vascular barriers dysfunction, including interaction with cell-surface receptors and intracellular signaling pathways. 相似文献
99.
François Fagotto 《EMBO reports》2013,14(5):422-433
After two decades of stardom, one would think that β‐catenin has revealed all of its most intimate details. Yet the essence of its duality has remained mysterious—how can a single protein both be the core link between cadherins and the cytoskeleton, and the nuclear messenger for Wnt signalling? On the basis of the available evidence and on molecular and evolutionary considerations, I propose that β‐catenin was a born nuclear transport receptor, which by interacting with adhesion molecules acquired the property to coordinate nuclear functions with cell–cell adhesion. While Wnt signalling diverted this activity, the original pathway might still function in modern eukaryotes. 相似文献
100.
Marilisa Villano Annalisa Borghini Mirko Manetti Erica Gabbrielli Antonella Rossi Piersante Sestini Anna Franca Milia Francesca Nacci Serena Guiducci Marco Matucci-Cerinic Lidia Ibba-Manneschi Elisabetta Weber 《Arthritis research & therapy》2013,15(4):R90