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排序方式: 共有176条查询结果,搜索用时 15 毫秒
21.
Deepika K. S. Rathore N. S. Saxena 《Applied Physics A: Materials Science & Processing》2010,98(2):441-448
Se58Ge42−x
Pb
x
(9≤x≤20) glasses have been prepared using conventional melt quenching technique. Differential Scanning Calorimetric (DSC) measurements
show single glass transition and double crystallization, which indicate the occurrence of phase separation in the samples.
The phases present in the samples were identified using XRD. The kinetics of the glass transition has been studied in terms
of the variation of glass transition temperature with composition and heating rate. In addition to this, activation energy
of the glass transition (E
t
) has also been evaluated and its composition dependence is also investigated. The thermal stability of these glasses has
been investigated using various stability criteria: Deiztal first glass criterion, ΔT, Saad and Poulain weighted thermal stability, H′ and the S-parameter. The values of these parameters were obtained using various characteristic temperatures such as the glass transition
temperature, T
g
, the onset temperature of crystallization, T
c
, and the peak crystallization temperature, T
p
. The values of stability parameters show that the phase corresponding to second crystallization is more stable than the phase
corresponding to first one. The stability in terms of the lead (Pb) content has been determined considering the values of
stability parameters of the phase corresponding to second peak. It was found that the stability increases with the lead content. 相似文献
22.
23.
Murugesan Dinesh Subramanyam Deepika Rajendran HarishKumar Chinnadurai Immanuel Selvaraj Selvaraj Mohana Roopan 《Applied biochemistry and biotechnology》2018,185(2):450-463
The current study indicates that octyl-β-D-glucopyranoside (OGP) as a detergent which has the ability to make the lipid layer stiff. OGP was subjected for toxicity studies and in vitro cytotoxicty assays on cancerous HeLa and non-cancerous myoblasts H9c2 cell lines. Test against aquatic organisms were carried out in Artemia salina and LC50 values were calculated. Hemolytic activity tested for blood bio-compalibity showed hemolysis rate of 10–16%, followed by thrombolytic activity to burst the clots in blood. Also, the samples showed good lysis when compared to the standard streptokinase. Furthermore, α-amylase activity has been carried out to check the inhibition of α-amylase by the OGP. Finally, antibacterial activity has been tested against four different pathogens and their MIC values have been calculated. 相似文献
24.
Vera B. Ivleva Nicole A. Schneck Deepika Gollapudi Frank Arnold Jonathan W. Cooper Q. Paula Lei 《Journal of the American Society for Mass Spectrometry》2018,29(7):1512-1523
CAP256 is one of the highly potent, broadly neutralizing monoclonal antibodies (bNAb) designed for HIV-1 therapy. During the process development of one of the constructs, an unexpected product-related impurity was observed via microfluidics gel electrophoresis. A panel of complementary LC-MS analyses was applied for the comprehensive characterization of CAP256 which included the analysis of the intact and reduced protein, the middle-up approach, and a set of complementary peptide mapping techniques and verification of the disulfide bonds. The designed workflow allowed to identify a clip within a protruding acidic loop in the CDR-H3 region of the heavy chain, which can lead to the decrease of bNAb potency. This characterization explained the origin of the additional species reflected by the reducing gel profile. An intra-loop disulfide bond linking the two fragments was identified, which explained why the non-reducing capillary electrophoresis (CE) profile was not affected. The extensive characterization of CAP256 post-translational modifications was performed to investigate a possible cause of CE profile complexity and to illustrate other structural details related to this molecule’s biological function. Two sites of the engineered Tyr sulfation were verified in the antigen-binding loop, and pyroglutamate formation was used as a tool for monitoring the extent of antibody clipping. Overall, the comprehensive LC-MS study was crucial to (1) identify the impurity as sequence clipping, (2) pinpoint the clipping location and justify its susceptibility relative to the molecular structure, (3) lead to an upstream process optimization to mitigate product quality risk, and (4) ultimately re-engineer the sequence to be clip-resistant. 相似文献
25.
26.
Structurally diverse annulated pyridopyrimidines have been synthesized by an efficient and environmentally benign synthetic protocol involving catalyzed four-component reaction of 2-aminobenzothiazoles with thiophene-2-carbaldehyde and carbonyl compounds in ethanol. Mild reaction conditions, operational simplicity, and structural diversity with excellent yields are some special attractions of the present protocol. 相似文献
27.
28.
The shift of the uncoupled OH stretching frequency of water (from its free state position) in crystal hydrates has been plotted against a parameter r0 obtained by subtracting the H-bond (OH...Y) length from the sum of the free state ionic radii of O and Y. From an analysis of this curve it is inferred that MOw coordination in hydrates reduces the ionic size of water oxygen and its effect on the OH stretching frequency is opposite to that of H-bonding. 相似文献
29.
30.
Akshita Khandelwal Danish Khan Jyoti Kuntail Indrajit Sinha 《International journal of quantum chemistry》2024,124(1):e27237
Reducing p-nitrophenol (PNP) to p-aminophenol is an industrially relevant synthesis. Nevertheless, only a few heterogeneous catalysts have been evaluated for the reduction of PNP by glycerol. Appropriate quantum computational studies can screen potential catalysts for this crucial green reaction. The present research investigates the catalytic activities of Pd@Ag and Ni@Ag core-shell nanogeometries toward PNP reduction by glycerol through density functional theory (DFT) calculations. The central atom of a geometry-optimized 13-atom Ag cluster was replaced by Pd and Ni atoms to create the core-shell morphologies. The interaction energies of PNP and glycerol with each of the (metal/bimetallic) clusters were evaluated by DFT calculations to find the best PNP and glycerol molecule orientation with the respective bimetallic cluster. Electrostatic potential surface and natural bond orbital analyses were performed to study the charge distribution and transfer between atomic orbitals. The frequencies of vibrational modes in isolated PNP/glycerol structures were compared to those when these molecules were in the presence of the different metal clusters to infer the effect of the interactions. All performed analyses indicated improved catalytic activity toward PNP reduction by glycerol upon Ni-doping of the Ag13 cluster. 相似文献