全文获取类型
收费全文 | 737篇 |
免费 | 73篇 |
国内免费 | 1篇 |
专业分类
811篇 |
出版年
2023年 | 2篇 |
2022年 | 2篇 |
2021年 | 8篇 |
2020年 | 12篇 |
2019年 | 9篇 |
2018年 | 18篇 |
2017年 | 23篇 |
2016年 | 30篇 |
2015年 | 41篇 |
2014年 | 40篇 |
2013年 | 46篇 |
2012年 | 57篇 |
2011年 | 60篇 |
2010年 | 36篇 |
2009年 | 39篇 |
2008年 | 54篇 |
2007年 | 49篇 |
2006年 | 48篇 |
2005年 | 50篇 |
2004年 | 50篇 |
2003年 | 28篇 |
2002年 | 35篇 |
2001年 | 6篇 |
2000年 | 10篇 |
1999年 | 12篇 |
1998年 | 12篇 |
1997年 | 3篇 |
1996年 | 5篇 |
1995年 | 4篇 |
1994年 | 4篇 |
1993年 | 3篇 |
1992年 | 2篇 |
1991年 | 4篇 |
1990年 | 1篇 |
1986年 | 1篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1980年 | 2篇 |
1979年 | 1篇 |
1973年 | 1篇 |
1970年 | 1篇 |
排序方式: 共有811条查询结果,搜索用时 15 毫秒
91.
We developed a surface micropatterning technique to control the cell adhesion and protein adsorption. This micropatterned array system was fabricated by a photolithography technique and self-assembled monolayer (SAM) deposition. It was hypothesized that the wettability and functional terminal group would regulate cell adhesion and protein adsorption. To demonstrate this hypothesis, glass-based micropatterned arrays with various functional terminal groups, such as amine (NH(2)) group (3-aminopropyl-triethoxysilane, APT), methyl (CH(3)) group (trichlorovinylsilane, TVS), and fluorocarbon (CF(3)) group (trichloro(1H, 1H, 2H, 2H-perfluorooctyl)silane, FOTS), were used. The contact angle was measured to determine the hydrophilic and hydrophobic properties of materials, demonstrating that TVS and FOTS were hydrophobic, whereas APTs were relatively hydrophilic. The cell adhesion was significantly affected by the wettability, showing that the cells were not adhered to hydrophobic surfaces, such as TVS and FOTS. Thus, the cells were selectively adhered to glass substrates within TVS- and FOTS-based micropatterned arrays. However, the cells were randomly adhered to APTs-based micropatterned arrays due to hydrophilic property of APTs. Furthermore, the protein adsorption of the SAM-based micropatterned array was analyzed, showing that the protein was more absorbed to the TVS surface. The surface functional terminal group enabled the control of protein adsorption. Therefore, this SAM-based micropatterned array system enabled the control of cell adhesion and protein adsorption and could be a potentially powerful tool for regulating the cell-cell interactions in a well-defined microenvironment. 相似文献
92.
93.
Lee JS Cho YS Chang MH Koh HY Chung BY Pae AN 《Bioorganic & medicinal chemistry letters》2003,13(22):4117-4120
A series of isoxazolyl tetrahydropyridinyl oxazolidinones with various substituents at the 3-position of the isoxazole ring have been synthesized and their in vitro antibacterial activities (MIC) were evaluated against several Gram-positive strains including the resistant strains of Staphyloccus and Enterococcus, such as MRSA and VRE. One of the most potent compounds synthesized, 4f, showed comparable or better activity against selected bacterial strains than those of linezolid and vancomycin. 相似文献
94.
Zhao H Patra A Yeh CC Tanaka Y Oh BR Dahiya R 《Biochemical and biophysical research communications》2002,292(2):482-491
We hypothesize that various growth factors and their receptors gene and protein are modulated in dorsal and ventral lobes of aging prostate. To test this hypothesis, TGFbeta1, TGFbeta2 TGFbeta3, TGFbetaR-I, TGFbetaR-II, TGFalpha, EGF, EGFR, KGF and KGFR gene and protein expression were analyzed in dorsal and ventral lobes of aging rat prostates (1, 3, 6, 9, 12, 18, 24, and 28/30 months). KGF gene expression was very weak or absent in 1, 3, and 6 month old rat dorsal and ventral lobes of prostate whereas it re-expressed in 9, 12, 18, 24 and 30 month old rat prostate. All growth factors and their receptors expect KGF and EGFR were mainly localized in epithelium of ventral and dorsal lobes of aging rat prostates. EGF, TGFalpha, TGFbeta1, and TGFbetaR-I protein expression was lacking in stroma of dorsal and ventral lobes of 1, 3, 6, 9, 12/18 months old rat prostates. However, EGF, TGFbeta1 and TGFbetaR-I proteins re-expressed in stroma of 24 and 28 months old rat prostates. KGF protein expression was lacking in epithelium of dorsal and ventral lobes of all aging rat prostates. This is the first report to demonstrate differential gene and protein expression of growth factors in dorsal and ventral lobes is associated with aging rat prostate, suggesting their role in pathogenesis of prostatic diseases with aging. 相似文献
95.
Grzegorzewski KJ Yao XT Kreider B Olsen HS Morris TS Zhang L Sanyal I Nardelli B Zukauskas D Brewer L Bong GW Kim Y Garotta G Salcedo TW 《Cytokine》2001,13(4):209-219
Myeloid progenitor inhibitory factor (MPIF)-2 is a beta-chemokine with select and potent activities on eosinophils and myeloid progenitors. In the beta-chemokine family, biological activity is modulated by differential processing of the amino-terminus. Here, for MPIF-2, we describe the biological activities of NH(2)-terminal deletion mutants and compare regions necessary for eosinophil and myeloid progenitor activities. Five MPIF-2 proteins with deletions at the amino-terminus were produced in Escherichia coli and assayed for calcium mobilization, chemotaxis and receptor binding activities on eosinophils, and for their ability to inhibit colony formation of human myeloid bone marrow progenitors. For eosinophils, deletion of the first two amino acids did not markedly alter activity, while subsequent truncations result in a complete loss of activity. One of the MPIF-2 mutants, MPIF-2 (P30-R99) was converted from an agonist to an antagonist of eotaxin, MPIF-2 and MCP-4 functional responses in eosinophil calcium flux and chemotaxis assays. Surprisingly, while displaying a complete loss of agonist activity toward eosinophils, MPIF-2 (P30-R99) retains ability to inhibit human bone marrow myeloid progenitor cell colony formation. In addition, processing at the amino terminus of MPIF-2 in vivo, may result in a chemokine with altered biological activities. 相似文献
96.
Sihyun Sung Fuyang Li Young Bong Park Jin Seok Kim Ae-Kyoung Kim Ok-kyu Song Jiae Kim Jun Che Sang Eun Lee Yunje Cho 《The EMBO journal》2014,33(20):2422-2435
The Mre11–Rad50–Nbs1 (MRN) complex plays important roles in sensing DNA damage, as well as in resecting and tethering DNA ends, and thus participates in double-strand break repair. An earlier structure of Mre11 bound to a short duplex DNA molecule suggested that each Mre11 in a dimer recognizes one DNA duplex to bridge two DNA ends at a short distance. Here, we provide an alternative DNA recognition model based on the structures of Methanococcus jannaschii Mre11 (MjMre11) bound to longer DNA molecules, which may more accurately reflect a broken chromosome. An extended stretch of B-form DNA asymmetrically runs across the whole dimer, with each end of this DNA molecule being recognized by an individual Mre11 monomer. DNA binding induces rigid-body rotation of the Mre11 dimer, which could facilitate melting of the DNA end and its juxtaposition to an active site of Mre11. The identified Mre11 interface binding DNA duplex ends is structurally conserved and shown to functionally contribute to efficient resection, non-homologous end joining, and tolerance to DNA-damaging agents when other resection enzymes are absent. Together, the structural, biochemical, and genetic findings presented here offer new insights into how Mre11 recognizes damaged DNA and facilitates DNA repair. 相似文献
97.
Sergey Ryzhov Bong Hwan Sung Qinkun Zhang Alissa Weaver Richard J. Gumina Italo Biaggioni Igor Feoktistov 《Purinergic signalling》2014,10(3):477-486
Adenosine levels increase in ischemic hearts and contribute to the modulation of that pathological environment. We previously showed that A2B adenosine receptors on mouse cardiac Sca1+CD31− mesenchymal stromal cells upregulate secretion of paracrine factors that may contribute to the improvement in cardiac recovery seen when these cells are transplanted in infarcted hearts. In this study, we tested the hypothesis that A2B receptor signaling regulates the transition of Sca1+CD31− cells, which occurs after myocardial injury, into a myofibroblast phenotype that promotes myocardial repair and remodeling. In vitro, TGFβ1 induced the expression of the myofibroblast marker α-smooth muscle actin (αSMA) and increased collagen I generation in Sca1+CD31− cells. Stimulation of A2B receptors attenuated TGFβ1-induced collagen I secretion but had no effect on αSMA expression. In vivo, myocardial infarction resulted in a rapid increase in the numbers of αSMA-positive cardiac stromal cells by day 5 followed by a gradual decline. Genetic deletion of A2B receptors had no effect on the initial accumulation of αSMA-expressing stromal cells but hastened their subsequent decline; the numbers of αSMA-positive cells including Sca1+CD31− cells remained significantly higher in wild type compared with A2B knockout hearts. Thus, our study revealed a significant contribution of cardiac Sca1+CD31− cells to the accumulation of αSMA-expressing cells after infarction and implicated A2B receptor signaling in regulation of myocardial repair and remodeling by delaying deactivation of these cells. It is plausible that this phenomenon may contribute to the beneficial effects of transplantation of these cells to the injured heart.
Electronic supplementary material
The online version of this article (doi:10.1007/s11302-014-9410-y) contains supplementary material, which is available to authorized users. 相似文献98.
Solar Cells: Triple‐Layer Structured Composite Separator Membranes with Dual Pore Structures and Improved Interfacial Contact for Sustainable Dye‐Sensitized Solar Cells (Adv. Energy Mater. 13/2014) 下载免费PDF全文
99.
Young Bong CHOI Edward William HARHAJ 《生物学前沿》2014,(6):423-436
Between 15% and 20% of human cancers are associated with infection by oncogenic viruses. Oncogenic viruses, including HPV, HBV, HCV and HTLV-1, target mitochondria to influence cell proliferation and survival. Oncogenic viral gene products also trigger the production of reactive oxygen species which can elicit oxidative DNA damage and potentiate oncogenic host signaling pathways. Viral oncogenes may also subvert mitochondria quality control mechanisms such as mitophagy and metabolic adaptation pathways to promote virus replication. Here, we will review recent progress on viral regulation of mitophagy and metabolic adaptation and their roles in viral oncogenesis. 相似文献
100.
Chang Hee Jung You-Cheol Hwang Kwang Joon Kim Bong Soo Cha Cheol-Young Park Won Seon Jeon Jae Hyeon Kim Sang-Man Jin Sang Youl Rhee Jeong-taek Woo Byung-Wan Lee 《PloS one》2014,9(4)