全文获取类型
收费全文 | 347篇 |
免费 | 18篇 |
出版年
2023年 | 1篇 |
2022年 | 1篇 |
2021年 | 10篇 |
2020年 | 5篇 |
2019年 | 3篇 |
2018年 | 6篇 |
2017年 | 7篇 |
2016年 | 12篇 |
2015年 | 8篇 |
2014年 | 15篇 |
2013年 | 24篇 |
2012年 | 42篇 |
2011年 | 24篇 |
2010年 | 12篇 |
2009年 | 11篇 |
2008年 | 24篇 |
2007年 | 20篇 |
2006年 | 15篇 |
2005年 | 12篇 |
2004年 | 14篇 |
2003年 | 19篇 |
2002年 | 21篇 |
2001年 | 2篇 |
2000年 | 1篇 |
1999年 | 8篇 |
1998年 | 1篇 |
1997年 | 4篇 |
1995年 | 1篇 |
1994年 | 4篇 |
1993年 | 1篇 |
1992年 | 4篇 |
1991年 | 2篇 |
1990年 | 4篇 |
1989年 | 4篇 |
1988年 | 3篇 |
1987年 | 3篇 |
1986年 | 2篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1983年 | 2篇 |
1982年 | 3篇 |
1981年 | 2篇 |
1979年 | 1篇 |
1978年 | 1篇 |
1973年 | 2篇 |
1970年 | 1篇 |
1969年 | 1篇 |
排序方式: 共有365条查询结果,搜索用时 31 毫秒
1.
K Phadke 《Biochemical and biophysical research communications》1987,142(2):448-453
The unfractionated macrophage-conditioned medium stimulates the chondrocytes to produce high levels of proteases. Purified IL-1 preparations exhibit significantly lower activity towards chondrocytes. This IL-1 mediated effect can be enhanced in presence of fibroblast growth factor, suggesting that other factors may collaborate with IL-1, in events leading to the cartilage destruction in vivo. 相似文献
2.
The biosynthesis of nucleic acids and proteins was studied in rat uterus by following the incorporation of [3H]-thymidine, [3H]-uridineand[14C]-leucinein control and pregnant rats in the presence and absence of two anti-implantation drugs. One of the drugs, 78/224
caused a significant increase in incorporation whereas the other drug, Centchroman, caused an inhibition in incorporation
of all the three precursors. The implications of these changes in the light of estrogenicity, agonist and antagonist actions
of anti-estrogens have been analysed. The importance of homeostatic mechanisms involved in nucleic acids and proteins for
the maintenance of constant internal milieu for blastocyst attachment has been discussed. 相似文献
3.
Magnetic resonance studies reveal a marked difference between the binding of α-tocopherol and that of the corresponding acetate (vitamin E acetate) with dipalmitoylphosphatidylcholine (DPPC) vesicles. This is reflected in differences in the phase-transition curves of the DPPC vesicles incorporated with the two compounds, as well as in the 13C relaxation times and line widths. A model for the incorporation of these molecules in lipid bilayers has been suggested. α-Tocopherol binds strongly with the lipids, possibly through a hydrogen bond formation between the hydroxyl group of the former and one of the oxygen atoms of the latter. The possibility of such a hydrogen bond formation is excluded in vitamin E acetate, which binds loosely through the normal hydrophobic interaction. The model for lipid-vitamin interaction explains the in vitro decomposition of H2O2 by α-tocopherol. α-Tocopherol in conjuction with H2O2 can also act as a free-radical scavenger in the lipid phase. The incorporation of α-tocopherol and vitamin E acetate in DPPC vesicles enhances the permeability of lipid bilayers for small molecules such as sodium ascorbate. 相似文献
4.
Susan L. Brandow David C. Turner Banahalli R. Ratna Bruce P. Gaber 《Biophysical journal》1993,64(3):898-902
The atomic force microscope (AFM) was used to structurally modify supported lipid bilayers in a controlled quantitative manner. By increasing the force applied by the AFM tip, lipid was removed from the scanned area, leaving a cut through the lipid bilayer. Cuts were repaired with the AFM by scanning the region with a controlled force and driving lipid back into the cut. A slow self-annealing of cuts was also observed. 相似文献
5.
Shridhara Alva Swati Sen Gupta Ratna S. Phadke Girjesh Govil 《Biosensors & bioelectronics》1991,6(8):663-668
Glucose oxidase has been immobilized onto a thin platinum strip, by co-crosslinking with bovine serum albumin and glutaraldehyde. The retention of redox characteristics of glucose oxidase has been verified by cyclic voltammetry. The activity of the immobilized enzyme reduces to a quarter of its value when the enzyme is in solution but improves when coimmobilized with 1
urea. The potentiometric response builds up and remains stable after 100 s. It is sensitive to the thickness of the immobilizing matrix, pH and temperature. An improvement in the performance of the electrode has been achieved by coimmobilizing 2
urea and metal ions such as Mg2+ and Mn2+. The presence of Cu has been proved to be detrimental. The electrode has been calibrated in the 0.1–5.0 mM glucose concentration range. It gives a stable response for more than 50 independent assays and can be stored for 60 days without significant loss of function. 相似文献
6.
7.
Mycobacillin non-producers, whether sporogenous or asporogenous, possess less exoprotease, but effective exoprotease producers are not always good mycobacillin yielders. There might exist a minimum level of exoprotease formation for elaboration of mycobacillin. 相似文献
8.
9.
2,2,6,6-Tetramethyl piperidine-N-oxyl nitroxyls are known to partition between aqueous and lipid phases, thus serving as probes to study membrane dynamics. The synthesis of a novel steroidal spin label, 3alpha-hydroxycholan-24-yl-(2",2",6",6"-tetramethyl-N-oxyl)p iperidyl butan-1',4'-dioate, containing 2,2,6,6-tetramethylpiperidine-N-oxyl moiety covalently bonded to the side chain in 3,24-caprostan-diol has been described. The localization of this spin label in model biomembranes has been studied by using electron spin resonance, differential scanning calorimetry, and 1H and 31P NMR spectroscopic techniques. Its applicability in studying the phase transition properties of model membrane L-alpha-dipalmitoyl phosphatidyl choline in the presence and absence of drugs has been described by using electron spin resonance. The label has also been used to study the permeability of epinephrine into membrane. The results have shown the applicability of the spin label as a potential spin probe in the study of biomembranes. 相似文献
10.
Bacteria show asymmetric subcellular distribution of many proteins involved in diverse cellular processes such as chemotaxis, motility, actin polymerization, chromosome partitioning and cell division. In many cases, the specific subcellular localization of these proteins is critical for proper regulation and function. Although cellular organization of the bacterial cell clearly plays an important role in cell physiology, systematic studies to uncover asymmetrically distributed proteins have not been reported previously. In this study, we undertook a proteomics approach to uncover polar membrane proteins in Escherichia coli. We identified membrane proteins enriched in E. coli minicells using a combination of two-dimensional electrophoresis and mass spectrometry. Among a total of 173 membrane protein spots that were consistently detected, 36 spots were enriched in minicell membranes, whereas 15 spots were more abundant in rod cell membranes. The minicell-enriched proteins included the inner membrane proteins MCPs, AtpA, AtpB, YiaF and AcrA, the membrane-associated FtsZ protein and the outer membrane proteins YbhC, OmpW, Tsx, Pal, FadL, OmpT and BtuB. We immunolocalized two of the minicell-enriched proteins, OmpW and YiaF, and showed that OmpW is a bona fide polar protein whereas YiaF displays a patchy membrane distribution with a polar and septal bias. 相似文献