全文获取类型
收费全文 | 450篇 |
免费 | 29篇 |
专业分类
479篇 |
出版年
2023年 | 4篇 |
2022年 | 4篇 |
2021年 | 14篇 |
2020年 | 5篇 |
2019年 | 5篇 |
2018年 | 8篇 |
2017年 | 11篇 |
2016年 | 12篇 |
2015年 | 16篇 |
2014年 | 17篇 |
2013年 | 30篇 |
2012年 | 25篇 |
2011年 | 30篇 |
2010年 | 13篇 |
2009年 | 11篇 |
2008年 | 14篇 |
2007年 | 27篇 |
2006年 | 16篇 |
2005年 | 26篇 |
2004年 | 15篇 |
2003年 | 18篇 |
2002年 | 13篇 |
2001年 | 14篇 |
2000年 | 8篇 |
1999年 | 9篇 |
1997年 | 3篇 |
1996年 | 3篇 |
1995年 | 10篇 |
1994年 | 7篇 |
1992年 | 9篇 |
1991年 | 5篇 |
1990年 | 6篇 |
1989年 | 2篇 |
1988年 | 2篇 |
1986年 | 5篇 |
1985年 | 5篇 |
1984年 | 7篇 |
1983年 | 3篇 |
1982年 | 4篇 |
1981年 | 5篇 |
1980年 | 4篇 |
1977年 | 3篇 |
1975年 | 3篇 |
1974年 | 5篇 |
1973年 | 4篇 |
1972年 | 5篇 |
1970年 | 2篇 |
1968年 | 2篇 |
1967年 | 1篇 |
1966年 | 1篇 |
排序方式: 共有479条查询结果,搜索用时 0 毫秒
471.
Summary Proteoliposomes made by a butanol-sonication technique from electric organ presynaptic membranes showed choline transport activity. In contrast to intact nerve terminals, the uptake of choline was dissociated from its conversion to acetylcholine in this preparation. The kinetics of choline uptake by proteoliposomes was best described by two Michaelis-Menten components. At a low concentration of choline, uptake was inhibited by hemicholinium-3 and required external Na+ and, thus, closely resembled high-affinity choline uptake by intact cholinergic nerve terminals. Choline transport could be driven by the Na+ gradient and by the transmembrane potential (inside negative) but did not directly require ATP. External Cl–, but not a Cl– gradient, was needed for choline transport activity. It is suggested that internal K+ plays a role in the retention of choline inside the proteoliposome. Proteoliposomes should prove a useful tool for both biochemical and functional studies of the highaffinity choline carrier.Abbreviations ACh
acetylcholine
- HC-3
hemicholinium-3
- ChAT
choline acetyltransferase 相似文献
472.
473.
474.
Haw Hsiao Chen-Yen Lin Sunil Vyas Kuang-Yuh Huang J. Andrew Yeh Yuan Luo 《Journal of biophotonics》2021,14(2):e202000335
Confocal endoscopy has been widely used to obtain fine optically sectioned images. However, confocal endomicroscopic images are formed by point-by-point scanning in both lateral and axial directions, which results in long image acquisition time. Here, an endomicroscope with telecentric configuration is presented to achieve nonmechanical and rapid axial scanning for volumetric fluorescence imaging. In our system, optical sectioning in wide-field fashion is obtained through HiLo imaging with a digital micromirror device. Axial scanning, without mechanical moving parts, is conducted by digital focus adjustment using an electrically tunable lens, offering constant magnification and contrast. We demonstrate imaging performance of our system with optically sectioned images using fluorescently labeled beads, as well as ex vivo mice cardiac tissue samples. Our system provides multiple advantages, in terms of improved scanning range, and reduced image acquisition time, which shows great potentials for three-dimensional biopsies of volumetric biological samples. 相似文献
475.
476.
Jay Vyas Ronald J Nowling Thomas Meusburger David Sargeant Krishna Kadaveru Michael R Gryk Vamsi Kundeti Sanguthevar Rajasekaran Martin R Schiller 《BMC bioinformatics》2010,11(1):328
Background
Minimotifs are short peptide sequences within one protein, which are recognized by other proteins or molecules. While there are now several minimotif databases, they are incomplete. There are reports of many minimotifs in the primary literature, which have yet to be annotated, while entirely novel minimotifs continue to be published on a weekly basis. Our recently proposed function and sequence syntax for minimotifs enables us to build a general tool that will facilitate structured annotation and management of minimotif data from the biomedical literature. 相似文献477.
Min Hsu Tiphaine C. Martin Nikki S. Vyas Garrett Desman Karen Mendelson Basil Horst Ramon E. Parsons Julide Tok Celebi 《Pigment cell & melanoma research》2023,36(5):407-415
In melanoma, immune cell infiltration into the tumor is associated with better patient outcomes and response to immunotherapy. T-cell non-inflamed tumors (cold tumors) are associated with tumor cell-intrinsic Wnt/β-catenin activation, and are typically resistant to anti-PD-1 alone or in combination with anti-CTLA-4 therapy. Reversal of the ‘cold tumor’ phenotype and identifying new effective immunotherapies are challenges. We sought to investigate the role of a newer immunotherapy agent, B7-H3, in this setting. RNA sequencing was used to identify co-targeting strategies upon B7-H3 inhibition in a well-defined preclinical melanoma model driven by β-catenin. We found that immune checkpoint molecule B7-H3 confers a suppressive tumor microenvironment by modulating antiviral signals and innate immunity. B7-H3 inhibition led to an inflamed microenvironment, up-regulation of CD47/SIRPa signaling, and together with blockade of the macrophage checkpoint CD47 resulted in additive antitumor responses. We found that the antitumor effects of the B7-H3/CD47 antibody combination were dependent on cytokine signaling pathways (CCR5/CCL5 and IL4). 相似文献
478.
K Plaut R Maple C Vyas S Munaim A Darling T Casey J R Alberts 《Proceedings of the Society for Experimental Biology and Medicine. Society for Experimental Biology and Medicine (New York, N.Y.)》1999,222(1):85-89
The effects of spaceflight on mammary metabolism of 10 pregnant rats was measured on Day 20 of pregnancy and after parturition. Rats were flown on the space shuttle from Day 11 through Day 20 of pregnancy. After their return to earth, glucose oxidation to carbon dioxide increased 43% (P < 0.05), and incorporation into fatty acids increased 300% (P < 0.005) compared to controls. It is unclear whether the enhanced glucose use is due to spaceflight or a response to landing. Casein mRNA and gross histology were not altered at Day 20 of pregnancy. Six rats gave birth (on Day 22 to 23 of pregnancy) and mammary metabolic activity was measured immediately postpartum. The earlier effects of spaceflight were no longer apparent. There was also no difference in expression of beta-casein mRNA. It is clear from these studies that spaceflight does not impair the normal development of the mammary gland, its ability to use glucose, nor the ability to express mRNA for a major milk protein. 相似文献
479.