全文获取类型
收费全文 | 41篇 |
免费 | 0篇 |
专业分类
化学 | 15篇 |
数学 | 8篇 |
物理学 | 18篇 |
出版年
2019年 | 1篇 |
2017年 | 2篇 |
2016年 | 1篇 |
2013年 | 1篇 |
2012年 | 1篇 |
2011年 | 2篇 |
2010年 | 1篇 |
2009年 | 1篇 |
2008年 | 2篇 |
2007年 | 1篇 |
2004年 | 2篇 |
2002年 | 3篇 |
2000年 | 1篇 |
1999年 | 1篇 |
1998年 | 1篇 |
1995年 | 1篇 |
1992年 | 1篇 |
1990年 | 2篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1985年 | 2篇 |
1984年 | 2篇 |
1981年 | 1篇 |
1980年 | 2篇 |
1979年 | 1篇 |
1978年 | 2篇 |
1977年 | 1篇 |
1976年 | 1篇 |
1973年 | 1篇 |
排序方式: 共有41条查询结果,搜索用时 31 毫秒
1.
2.
Masterson DS Yin H Chacon A Hachey DL Norris JL Porter NA 《Journal of the American Chemical Society》2004,126(3):720-721
Strategies are reported that combine in one step a predictable chemical-based protein digestion with mass spectrometry. Lysine residue amino groups in peptides and proteins are modified by reaction with a peroxycarbonate derived from p-nitrophenol, and tert-butyl hydroperoxide. The peroxycarbonate reacts with lysine residues in peptides and proteins, and the resulting lysine peroxycarbamates undergo homolytic fragmentation under conditions of low-energy collision-induced dissociation (CID). Observed fragmentation of the peptides involves apparent free radical processes including Hofmann-L?ffler-type rearrangements that lead to peptide chain fragmentation. Strategies for directed cleavage of peptides by free radical promoted processes are feasible, and such strategies may well simplify schemes for protein analysis. 相似文献
3.
[reaction: see text] Barton esters of beta-silylcarboxylic acids were decomposed by photolysis alone in organic solvents or in the presence of ethanesulfonyl azide or bromotrichloromethane. Products of the reaction, beta-silylthiopyridyl ethers, beta-silyl azides, or alkenes, were formed with significant control of stereochemistry. 相似文献
4.
R.R. Johnson T.G. Masterson K.L. Erdman A.W. Thomas R.H. Landau 《Nuclear Physics A》1978,296(3):444-460
We have measured the angular distribution of π+ elastically scattered from . The angular range was between 13° and 165° lab. Scattered pions were detected with two counter telescopes which required pion identification through the observation of the decay muon. Data agree well with calculations derived from the free πn scattering amplitudes when absorption effects have been included. 相似文献
5.
Dill AL Eberlin LS Costa AB Zheng C Ifa DR Cheng L Masterson TA Koch MO Vitek O Cooks RG 《Chemistry (Weinheim an der Bergstrasse, Germany)》2011,17(10):2897-2902
Diagnosis of human bladder cancer in untreated tissue sections is achieved by using imaging data from desorption electrospray ionization mass spectrometry (DESI-MS) combined with multivariate statistical analysis. We use the distinctive DESI-MS glycerophospholipid (GP) mass spectral profiles to visually characterize and formally classify twenty pairs (40 tissue samples) of human cancerous and adjacent normal bladder tissue samples. The individual ion images derived from the acquired profiles correlate with standard histological hematoxylin and eosin (H&E)-stained serial sections. The profiles allow us to classify the disease status of the tissue samples with high accuracy as judged by reference histological data. To achieve this, the data from the twenty pairs were divided into a training set and a validation set. Spectra from the tumor and normal regions of each of the tissue sections in the training set were used for orthogonal projection to latent structures (O-PLS) treated partial least-square discriminate analysis (PLS-DA). This predictive model was then validated by using the validation set and showed a 5% error rate for classification and a misclassification rate of 12%. It was also used to create synthetic images of the tissue sections showing pixel-by-pixel disease classification of the tissue and these data agreed well with the independent classification that uses histological data by a certified pathologist. This represents the first application of multivariate statistical methods for classification by ambient ionization although these methods have been applied previously to other MS imaging methods. The results are encouraging in terms of the development of a method that could be utilized in a clinical setting through visualization and diagnosis of intact tissue. 相似文献
6.
CM Thaker S Rayaprol Krushna Mavani DS Rana MS Sahasrabudhe SI Patil DG Kuberkar 《Pramana》2002,58(5-6):1035-1039
The effect of simultaneous substitution of a fluctuating cation and a divalent cation in LaMnO3 perovskite modifies the properties of the material to exhibit large valence colossal magnetoresistance (CMR) effect. A good
example of these properties is (La1−2x
Pr
x
Ca
x
)MnO3 (LPCMO) type CMR material. In this communication it is reported that, with the increase in x (for x=0.1, 0.15, 0.2), the T
c varies between 100 and 120 K with improvisation in metal-insulator transition. Interestingly, resistance increases with x from few hundred ohms to few kilo ohms with corresponding decrease in the unit cell volume. The results of the studies using
X-ray diffraction (XRD), electrical resistivity, magnetoresistance and ac susceptibility measurements on LPCMO samples for
understanding the structural, transport and magnetic properties are discussed in detail. 相似文献
7.
Yin H Chacon A Porter NA Masterson DS 《Journal of the American Society for Mass Spectrometry》2007,18(5):807-816
Protein identification is routinely accomplished by peptide sequencing using mass spectrometry (MS) after enzymatic digestion.
Site-specific chemical modification may improve peptide ionization efficiency or sequence coverage in mass spectrometry. We
report herein that amino group of lysine residue in peptides can be selectively modified by reaction with a peroxycarbonate
and the resulting lysine peroxycarbamates undergo homolytic fragmentation under conditions of low-energy collision-induced
dissociation (CID) in electrospray ionization (ESI) and matrix-assisted laser desorption and ionization (MALDI) MS. Selective
modification of lysine residue in peptides by our strategy can induce specific peptide cleavage at or near the lysine site.
Studies using deuterated analogues of modified lysine indicate that fragmentation of the modified peptides involves apparent
free-radical processes that lead to peptide chain fragmentation and side-chain loss. The formation of a-, c-, or z-types of
ions in MS is reminiscent of the proposed free-radical mechanisms in low-energy electron capture dissociation (ECD) processes
that may have better sequence coverage than that of the conventional CID method. This site-specific cleavage of peptides by
free radical- promoted processes is feasible and such strategies may aid the protein sequencing analysis and have potential
applications in top-down proteomics. 相似文献
8.
The isoscalar transition rates and neutron-stripping probabilities to states of 14C have been measured using the 35 MeV 14C(α, α')14C and 17.7 MeV 13C(d, p)14C reactions. States showing great charge asymmetries in pion scattering at 8.32 MeV (2+) and 11.7 MeV (4?) were examined in detail. Isoscalar transition rates B(02) were determined to be 168, 96 and 74 fm4 for the 7.01, 8.32 and 10.45 MeV 2+ states, with identical single-neutron spectroscopic factors of 0.065, from the (d, p) data, for the lowest two states. 相似文献
9.
B.M. Barnett W. Gyles R.R. Johnson K.L. Erdman J. Johnstone J.J. Kraushaar S. Lepp T.G. Masterson E. Rost D.R. Gill A.W. Thomas J. Alster I. Navon R.H. Landau 《Physics letters. [Part B]》1980,97(1):45-49
A new method using low energy π+ elastic scattering is employed to determine the proton matter distribution of a nucleus relative to an adjacent nucleus differing by one proton. The difference in the rms charge radii of 12C and 11B was determined to be 0.072 ± 0.021 fm with π+ beam energies of 38.6 and 47.7 MeV. 相似文献
10.
R.R. Johnson B. Bassalleck K. Erdman B. Gyles T. Marks T. Masterson D.R. Gill C. Sabev 《Physics letters. [Part B]》1978,78(5):560-563
We have measured the differential cross section for π? elastically scattered from . The scattered π? were detected with pion range telescopes. The measured angular distribution is compared with a momentum space optical potential calculation. Derived phase shifts are compared with those obtained from π+ data and from momentum and coordinate space calculations. 相似文献