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41.
Silvin P. Knight Louise Newman John D. OConnor James Davis Rose Anne Kenny Roman Romero-Ortuno 《Entropy (Basel, Switzerland)》2021,23(1)
In this cross-sectional study, the relationship between noninvasively measured neurocardiovascular signal entropy and physical frailty was explored in a sample of community-dwelling older adults from The Irish Longitudinal Study on Ageing (TILDA). The hypothesis under investigation was that dysfunction in the neurovascular and cardiovascular systems, as quantified by short-length signal complexity during a lying-to-stand test (active stand), could provide a marker for frailty. Frailty status (i.e., “non-frail”, “pre-frail”, and “frail”) was based on Fried’s criteria (i.e., exhaustion, unexplained weight loss, weakness, slowness, and low physical activity). Approximate entropy (ApEn) and sample entropy (SampEn) were calculated during resting (lying down), active standing, and recovery phases. There was continuously measured blood pressure/heart rate data from 2645 individuals (53.0% female) and frontal lobe tissue oxygenation data from 2225 participants (52.3% female); both samples had a mean (SD) age of 64.3 (7.7) years. Results revealed statistically significant associations between neurocardiovascular signal entropy and frailty status. Entropy differences between non-frail and pre-frail/frail were greater during resting state compared with standing and recovery phases. Compared with ApEn, SampEn seemed to have better discriminating power between non-frail and pre-frail/frail individuals. The quantification of entropy in short length neurocardiovascular signals could provide a clinically useful marker of the multiple physiological dysregulations that underlie physical frailty. 相似文献
42.
Wai Yi Kelly Chan T. W. Dominic Chan Peter B. O’Connor 《Journal of the American Society for Mass Spectrometry》2010,21(6):1012-1015
Electron-transfer dissociation (ETD) with supplemental activation of the doubly charged deamidated tryptic digested peptide
ions allows differentiation of isoaspartic acid and aspartic acid residues using the c + 57 or z • − 57 peaks. The diagnostic peak clearly localizes and characterizes the isoaspartic acid residue. Supplemental activation
in ETD of the doubly charged peptide ions involves resonant excitation of the charge reduced precursor radical cations and
leads to further dissociation, including extra backbone cleavages and secondary fragmentation. Supplemental activation is
essential to obtain a high quality ETD spectrum (especially for doubly charged peptide ions) with sequence information. Unfortunately,
the low-resolution of the ion trap mass spectrometer makes detection of the diagnostic peak, [M-60], for the aspartic acid
residue difficult due to interference with side-chain loss from arginine and glutamic acid residues. 相似文献
43.
Z. Zhong D. Chapman D. Connor A. Dilmanian N. Gmur M. Hasnah 《Synchrotron Radiation News》2013,26(6):27-34
The APS hosted a two-day workshop on Catalysis Research at the APS on September 12-13, 2005. The goal of the workshop was to evaluate current catalysis-related research at the APS and to plan future directions. The outcome of the meeting will be a report with recommendations to promote new, and support current, catalysis research at the APS. The workshop was attended by 82 participants representing industry, national laboratories, and universities. 相似文献
44.
45.
Goyer J.R. Connor K.A. Hickok R.L. Solensten L. 《IEEE transactions on plasma science. IEEE Nuclear and Plasma Sciences Society》1994,22(4):403-409
Two-dimensional electron temperature and density data have been obtained in the midplane of the non-axisymmetric magnetic confinement device ELMO Bumpy Torus (EBT) through the use of a heavy ion beam probe. This beam probe differs from others operated on toroidal or open magnetic geometries in its combination of complete computer control with the steady-state nature of EBT which allows, under normal operating conditions, for extensive calibration of the system in situ, minimizing both alignment and acquisition errors, along with the use of synchronous detection to dramatically improve the quality of the detected signal over what is typically possible in fast pulse devices. These techniques are important and applicable to long pulse devices where the beam probe may be an ideal diagnostic to measure, for example, parameters of the edge plasma. While the EBT beam probe was implemented to obtain profiles of plasma space potential, we have found that it can also be used effectively to measure the temperature and density profiles in the midplane between magnetic field coils. The data obtained support the contention that the formation of a hollow temperature profile in the T-Mode sufficiently inverts the plasma pressure such that stability of the core plasma would be expected even without diamagnetic effects from the hot electron rings which have previously been considered essential 相似文献
46.
Given densities μ and v, we characterize nonnegative matrices T such that the μ-statistical core of x equals the v-statistical core of Tx for every real-valued bounded sequence. 相似文献
47.
Results are presented of a photoemission study of the electronic structure of SiON layers formed by a pulsed-RF decoupled plasma nitration (DPN) of ultra-thin SiO2 grown base layers approximately 1.0 nm thick. The optical thickness of these device grade nitrided dielectric layers was in the range 1.4-1.6 nm. X-ray photoelectron spectroscopy (XPS) studies indicate that the nitrogen is incorporated in a single chemical environment at concentration levels in the range 15-17%. Angle resolved XPS measurements show that the nitrogen is distributed through the layer, with the binding energy of the N 1s peak at 398.3 eV which is indicative of a Si3N4-like chemical species in an oxide environment. High resolution core level photoemission studies of the spin orbit stripped Si 2p4+ peak revealed full width half maximum values in the range 1.4-1.55 eV, which are significantly larger than the 1.15 eV value reported for SiO2 layers. Synchrotron radiation photoemission studies of the valence band spectra enable the valence band off-set at the Si/SON interface to be evaluated as 2.3 eV and to infer a conduction band off-set of 2.1 eV. 相似文献
48.
Cailin O’Connor 《The Journal of mathematical sociology》2017,41(3):155-171
Why do minority groups tend to be discriminated against when it comes to situations of bargaining and resource division? In this article, I explore an explanation for this disadvantage that appeals solely to the dynamics of social interaction between minority and majority groups—the cultural Red King effect (Bruner, 2017). As I show, in agent-based models of bargaining between groups, the minority group will tend to get less as a direct result of the fact that they frequently interact with majority group members, while majority group members meet them only rarely. This effect is strengthened by certain psychological phenomenon—risk aversion and in-group preference—is robust on network models, and is strengthened in cases where preexisting norms are discriminatory. I will also discuss how this effect unifies previous results on the impacts of institutional memory on bargaining between groups. 相似文献
49.
Li X Huang Y O'Connor PB Lin C 《Journal of the American Society for Mass Spectrometry》2011,22(2):245-254
Performing collisionally activated dissociation (CAD) and electron capture dissociation (ECD) in tandem has shown great promise
in providing comprehensive sequence information that was otherwise unobtainable by using either fragmentation method alone
or in duet. However, the general applicability of this MS3 approach in peptide sequencing may be undermined by the formation of non-direct sequence ions, as sometimes observed under
CAD, particularly when multiple stages of CAD are involved. In this study, varied-sized doubly-charged b-ions from three tachykinin
peptides were investigated by ECD. Sequence scrambling was observed in ECD of all b-ions from neurokinin A (HKTDSFVGLM-NH2), suggesting the presence of N- and C-termini linked macro-cyclic conformers. On the contrary, none of the b-ions from eledoisin
(pEPSKDAFIGLM-NH2) produced non-direct sequence ions under ECD, as it does not contain a free N-terminal amino group. ECD of several b-ions
from Substance P (RPKPQQFFGLM-NH2) showed series of cm-Lys fragment ions which suggested that the macro-cyclic structure may also be formed by connecting the C-terminal carbonyl
group and the ε-amino group of the lysine side chain. Theoretical investigation of selected Substance P b-ions revealed several
low energy conformers, including both linear oxazolones and macro-ring structures, in corroboration with the experimental
observation. This study showed that a b-ion may exist as a mixture of several forms, with their propensities influenced by
its N-terminus, length, and certain side-chain groups. Further, the presence of several macro-cyclic structures may result
in erroneous sequence assignment when the combined CAD and ECD methods are used in peptide sequencing. 相似文献
50.
Sargaeva NP Lin C O'Connor PB 《Journal of the American Society for Mass Spectrometry》2011,22(3):480-491
Ion-electron reaction based fragmentation methods (ExD) in tandem mass spectrometry (MS), such as electron capture dissociation
(ECD) and electron transfer dissociation (ETD) represent a powerful tool for biological analysis. ExD methods have been used
to differentiate the presence of the isoaspartate (isoAsp) from the aspartate (Asp) in peptides and proteins. IsoAsp is a
β3-type amino acid that has an additional methylene group in the backbone, forming a Cα–Cβ bond within the polypeptide chain. Cleavage of this bond provides specific fragments that allow differentiation of the isomers.
The presence of a Cα–Cβ bond within the backbone is unique to β-amino acids, suggesting a similar application of ExD toward the analysis of peptides
containing other β-type amino acids. In the current study, ECD and ETD analysis of several β-amino acid containing peptides
was performed. It was found that N–Cβ and Cα–Cβ bond cleavages were rare, providing few c and z type fragments, which was attributed to the instability of the Cβ radical. Instead, the electron capture resulted primarily in the formation of a and y fragments, representing an alternative fragmentation pathway, likely initiated by the electron capture at a backbone amide
nitrogen protonation site within the β amino acid residues. 相似文献