全文获取类型
收费全文 | 301篇 |
免费 | 15篇 |
专业分类
316篇 |
出版年
2023年 | 2篇 |
2022年 | 2篇 |
2021年 | 4篇 |
2020年 | 2篇 |
2019年 | 3篇 |
2018年 | 3篇 |
2017年 | 4篇 |
2016年 | 8篇 |
2015年 | 15篇 |
2014年 | 9篇 |
2013年 | 23篇 |
2012年 | 26篇 |
2011年 | 17篇 |
2010年 | 21篇 |
2009年 | 20篇 |
2008年 | 25篇 |
2007年 | 12篇 |
2006年 | 19篇 |
2005年 | 14篇 |
2004年 | 9篇 |
2003年 | 10篇 |
2002年 | 14篇 |
2001年 | 10篇 |
2000年 | 3篇 |
1999年 | 6篇 |
1998年 | 3篇 |
1997年 | 2篇 |
1995年 | 1篇 |
1994年 | 1篇 |
1993年 | 2篇 |
1992年 | 1篇 |
1991年 | 2篇 |
1990年 | 1篇 |
1989年 | 4篇 |
1987年 | 3篇 |
1985年 | 1篇 |
1982年 | 2篇 |
1981年 | 6篇 |
1980年 | 1篇 |
1979年 | 4篇 |
1977年 | 1篇 |
排序方式: 共有316条查询结果,搜索用时 15 毫秒
131.
The linear polypeptide antibiotic alamethicin is known to form channels in artificial lipid membranes. Synthetic 13- and 17-residue alamethicin fragments, labelled with a fluorescent dansyl group at the N-terminus, have been shown to translocate divalent cations across phospholipid membranes and to uncouple oxidative phosphorylation in rat liver mitochondria, in a manner analogous to the parent peptides. From studies of the aqueous phase aggregation behavior of the peptides, as well as their interaction with rat liver mitochondria, it is concluded that the interaction of the peptides with membranes is a complex process, probably involving both aqueous and membrane phase aggregation. 相似文献
132.
The effect of rock salts, NaCI, propionic acid, NCP.75, plant products — asafoetida, turmeric powder and aqueous leaf extracts ofAzadirachta indica, Lawsonia alba, Pongamia glabra andTridax procumbens on seed colonization and aflatoxin production byAspergillus flavus (NRRL-3000) was studied in two Spanish bunch groundnut varieties (J-11 and JL-24). All these treatments inhibited seed colonization and aflatoxin production to varying degrees. Inhibition of seed colonization with chemicals, plant products and aqueous leaf extracts was observed to range between 17 to 96%, 27 to 100%, and 8 to 75% while inhibition of aflatoxin production ranged from 14 to 74%, 42 to 71%, and 6 to 64%, respectively. In general, salts (20g/L), propionic acid (10mL/L), asafoetida (pure Ig/L and impure 20g/L), andAzadirachta indica aqueous leaf extract (20 g/L) are better in preventing aflatoxin contamination in both the groundnut varieties. 相似文献
133.
134.
Recent studies implicate hyperglycemia as a cause of vascular complications in diabetes. Our study confirmed that high concentration of glucose (30 mM) induces apoptosis in cultures of human umbilical vein endothelial cells. After 5 days of culture TUNEL positive cells in high concentration of glucose were nearly 63% higher when compared to normal concentration of glucose (5 mM). Transfection of pcDNA3-rat alphaB-crystallin into these cells inhibited high glucose-induced apoptosis by approximately 36%, such an effect was not observed when cells were transfected with an empty vector. AlphaB-crystallin transfection inhibited by about 35% of high glucose induced activation of caspase-3. High concentration of glucose enhanced formation of reactive oxygen species (ROS) in these cells but this was significantly (p < 0.001) curtailed by transfection of alphaB-crystallin. Results of our study indicate that alphaB-crystallin effectively inhibits both ROS formation and apoptosis in cultured vascular endothelial cells and provide a basis for future therapeutic interventions in diabetic vascular complications. 相似文献
135.
G. Nagaraj A. Sukumar B. Nandlal S. Vellaichamy K. Thanasekaran A. L. Ramanathan 《Biological trace element research》2009,131(3):255-262
Element contents of teeth elucidate exposure nature, but less is known about association of tooth element concentrations of
diabetics and hypertensives with exposure profile. Present study aims to estimate copper, chromium, iron, zinc, nickel, and
lead concentrations in the permanent teeth of control, diabetic, and hypertensive subjects from Mysore. The results show that
lead levels of teeth (Pb-T) are higher in the hypertensives and diabetics, whereas copper levels of teeth (Cu-T) are lower
in the hypertensives and users of stainless steel utensils than that of controls and users of mixed utensils. The elevated
Cu-T levels found in the users of mixed utensils that being made of several metals are ascribed to leaching effect of sour
and spicy food of Indian cuisine. The element levels were influenced by diet (Zn-T), place of living, sex and income (Pb-T)
of the subjects, but not by age, drinking water from different sources, and certain habits viz., smoking, alcohol consumption,
chewing betel, and nut. Thus, it is evident that high Pb-T and low Cu-T levels may be related with diabetes and hypertension
and high Pb-T and Cu-T levels, respectively, in the urbanites, and the users of mixed utensils may show different exposure
profiles from environment and utensils. 相似文献
136.
Guanidinium chloride stimulates the activity of alkaline phosphatase from Escherichia coli, by 3-4-fold. Structural parameters of the enzyme, monitored by fluorescence and circular dichroism, indicate progressive denaturation. This unusual stimulation is shown to be independent of the nature of the substrate and source of the enzyme. Profiles of pH dependence and transphosphorylation reaction indicate that the dephosphorylation step of the catalysis is enhanced in the presence of guanidinium chloride. We demonstrate, by fast-flow kinetics and inhibitor titrations, that guanidinium chloride enhances activity by abolishing negative cooperativity and by accelerating the dissociation of rate-limiting enzyme and substrate (E.P) complex. 相似文献
137.
138.
Mulvenna J Hamilton B Nagaraj SH Smyth D Loukas A Gorman JJ 《Molecular & cellular proteomics : MCP》2009,8(1):109-121
Hookworms are blood-feeding intestinal parasites of mammalian hosts and are one of the major human ailments affecting approximately 600 million people worldwide. These parasites form an intimate association with the host and are able to avoid vigorous immune responses in many ways including skewing of the response phenotype to promote parasite survival and longevity. The primary interface between the parasite and the host is the excretory/secretory component, a complex mixture of proteins, carbohydrates, and lipids secreted from the surface or oral openings of the parasite. The composition of this complex mixture is for the most part unknown but is likely to contain proteins important for the parasitic lifestyle and hence suitable as drug or vaccine targets. Using a strategy combining the traditional technology of one-dimensional SDS-PAGE and the newer fractionation technology of OFFGEL electrophoresis we identified 105 proteins from the excretory/secretory products of the blood-feeding stage of the dog hookworm, Ancylostoma caninum. Highly represented among the identified proteins were lectins, including three C-type lectins and three beta-galactoside-specific S-type galectins, as well as a number of proteases belonging to the three major classes found in nematodes, aspartic, cysteine, and metalloproteases. Interestingly 28% of the identified proteins were homologous to activation-associated secreted proteins, a family of cysteine-rich secreted proteins belonging to the sterol carrier protein/Tpx-1/Ag5/PR-1/Sc-7 (TAPS) superfamily. Thirty-four of these proteins were identified suggesting an important role in host-parasite interactions. Other protein families identified included hyaluronidases, lysozyme-like proteins, and transthyretin-like proteins. This work identified a suite of proteins important for the parasitic lifestyle and provides new insight into the biology of hookworm infection. 相似文献
139.
Retinal capillary pericytes undergo premature death, possibly by apoptosis, during the early stages of diabetic retinopathy. The alpha-oxoaldehyde, methylglyoxal (MGO), has been implicated as a cause of cell damage in diabetes. We have investigated the role of MGO and its metabolizing enzyme, glyoxalase I, in high glucose-induced apoptosis (annexin V binding) of human retinal pericyte (HRP). HRP incubated with high glucose (30 mm d-glucose) for 7 days did not undergo apoptosis despite accumulation of MGO. However, treatment with a combination of high glucose and S-p-bromobenzylglutathione cyclopentyl diester, a competitive inhibitor of glyoxalase I, resulted in apoptosis along with a dramatic increase in MGO. Overexpression of glyoxalase I in HRP protected against S-p-bromobenzylglutathione cyclopentyl diester-induced apoptosis under high glucose conditions. Incubation of HRP with high concentrations of MGO resulted in an increase of apoptosis relative to untreated controls. We found an elevation of nitric oxide (NO.) in HRP that was incubated with high glucose when compared with those incubated with either the l-glucose or untreated controls. When HRP were incubated with an NO. donor, DETANONOATE ((Z)-1-[2-(2-aminoethyl)-N-(2-ammonioethyl)amino]diazen-1-ium-1,2-diolate), we observed both decreased glyoxalase I expression and activity relative to untreated control cells. Further studies showed that HRP underwent apoptosis when incubated with DETANONOATE and that apoptosis increased further on co-incubation with high glucose. Our findings indicate that glyoxalase I is critical for pericyte survival under hyperglycemic conditions, and its inactivation and/or down-regulation by NO. may contribute to pericyte death by apoptosis during the early stages of diabetic retinopathy. 相似文献
140.
Oxana V. Denisova Laura Kakkola Lin Feng Jakob Stenman Ashwini Nagaraj Johanna Lampe Bhagwan Yadav Tero Aittokallio Pasi Kaukinen Tero Ahola Suvi Kuivanen Olli Vapalahti Anu Kantele Janne Tynell Ilkka Julkunen Hannimari Kallio-Kokko Henrik Paavilainen Veijo Hukkanen Richard M. Elliott Jef K. De Brabander Xavier Saelens Denis E. Kainov 《The Journal of biological chemistry》2012,287(42):35324-35332