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31.
Mechanoluminescence,thermoluminescence, photoluminescence studies on Ca3Y2Si3O12:RE3+ (RE3+ = Dy3+and Eu3+) phosphors
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Dy3+ and Eu3+ activated Ca3Y2Si3O12 phosphors were synthesized by the solid‐state synthesis method. The phosphors were characterized by X‐ray diffraction (XRD), mechanoluminescence (ML), thermoluminescence (TL) and photoluminescence (PL) to determine structure and luminescence. For ML glow curves, only one peak was observed, as only one type of luminescence centre was formed during irradiation. The Ca3Y2Si3O12:Dy3+ TL glow curve showed a single peak at 151.55°C and the Ca3Y2Si3O12:Eu3+ TL glow curve peaked at 323°C with a small peak at 192°C, indicating that two types of traps were activated. The trapping parameters for both the samples were calculated using Chen's peak shape method. Dy3+‐activated Ca3Y2Si3O12 showed emission at 482 and 574 nm when excited by a 351 nm excitation wavelength, whereas the Eu3+‐activated Ca3Y2Si3O12 phosphor PL emission spectra showed emission peaks at 613 nm, 591 nm, 580 nm when excited at 395 nm wavelength. When excited at 466 nm, prominent emission peaks were observed at their respective positions with very slight shifts. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
32.
Arshid Hussain Ganie Altaf Ahmad Renu Pandey Ibrahim M. Aref Peerzada Yasir Yousuf Sayeed Ahmad Muhammad Iqbal 《PloS one》2015,10(6)
Background
Maize (Zea mays L.) is one of the most widely cultivated crop plants. Unavoidable economic and environmental problems associated with the excessive use of phosphatic fertilizers demands its better management. The solution lies in improving the phosphorus (P) use efficiency to sustain productivity even at low P levels. Untargeted metabolomic profiling of contrasting genotypes provides a snap shot of whole metabolome which differs under specific conditions. This information provides an understanding of the mechanisms underlying tolerance to P stress and the approach for increasing P-use-efficiency.Methodology/Principal Findings
A comparative metabolite-profiling approach based on gas chromatography-mass spectrometry (GC/MS) was applied to investigate the effect of P starvation and its restoration in low-P sensitive (HM-4) and low-P tolerant (PEHM-2) maize genotypes. A comparison of the metabolite profiles of contrasting genotypes in response to P-deficiency revealed distinct differences among low-P sensitive and tolerant genotypes. Another set of these genotypes were grown under P-restoration condition and sampled at different time intervals (3, 5 and 10 days) to investigate if the changes in metabolite profile under P-deficiency was restored. Significant variations in the metabolite pools of these genotypes were observed under P-deficiency which were genotype specific. Out of 180 distinct analytes, 91 were identified. Phosphorus-starvation resulted in accumulation of di- and trisaccharides and metabolites of ammonium metabolism, specifically in leaves, but decreased the levels of phosphate-containing metabolites and organic acids. A sharp increase in the concentrations of glutamine, asparagine, serine and glycine was observed in both shoots and roots under low-P condition.Conclusion
The new insights generated on the maize metabolome in resposne to P-starvation and restoration would be useful towards improvement of the P-use efficiency in maize. 相似文献33.
34.
In the present investigation, we have used adenosine triphosphatase (ATPase) activity as biochemical test of toxic action of lindane that was explained by lipid peroxidation model. Study was also undertaken to ascertain the potential protective role of alpha-lipoic acid (ALA) and vitamin E on the same parameters. Highly acute dose of lindane, i.e., 40 mg/kg bw for 18 h exposure, was used for creating lesions in brain. Lipid peroxidation was measured in terms of glutathione peroxidase and thio barbituric acid-reacting substances (TBARS). Various brain regions under investigation were cerebellum and pons-medulla oblongata. Healthy, male, Swiss mice (7–8 weeks old) were allocated into four groups. First group was control, second group was treated with lindane, third group was treated purely with antioxidants, and fourth group received both antioxidants and lindane treatment. Results revealed the significant difference (at 1% and 5% in all groups) in all studied parameters from control. Increased TBARS level in second group suggests that lindane enhances the production of free radicals in studied brain regions. Antioxidants under test are efficient remedy for neurotoxicity caused by lindane. We conclude that lindane manifests toxic effects on brain ATPase and enhances lipid peroxidation. ALA and vitamin E in combination may provide protection against lindane-induced acute toxicity. 相似文献
35.
The study is aimed at exploring the utility of thermoanalytical methods in the solid-state characterization of various crystalline
forms of nevirapine. The different forms obtained by recrystallization of nevirapine from various solvents were identified
using differential scanning calorimetry and thermogravimetric analysis (TGA). The appearance of desolvation peak accompanied
by weight loss in TGA indicated the formation of solvates: hemi-ethanolate (Form I), hemi-acetonitrilate (Form II), hemi-chloroformate
(Form III), hemi-THF solvate (Form IV), mixed hemi-ethanolate hemi-hydrate (Form V), and hemi-toluenate (Form VI). The higher
desolvation temperatures of all the solvates except toluenate than their respective boiling point indicate tighter binding
of solvent. Emphasis has been laid on the determination of heat capacity and heat of solution utilizing microreaction calorimeter
to further distinguish the various forms. The enthalpy of solution (ΔH
sol), an indirect measure of the lattice energy of a solid, was well correlated with the crystallinity of all the solid forms
obtained. The magnitude of ΔH
sol was found to be −14.14 kJ/mol for Form I and −2.83 kJ/mol for Form V in phosphate buffer of pH 2, exhibiting maximum ease
of molecular release from the lattice in Form I. The heat capacity for solvation (ΔC
p) was found to be positive, providing information about the state of solvent molecules in the host lattice. The solubility
and dissolution rate of the forms were also found to be in agreement with their enthalpy of solution. Form (I), being the
most exothermic, was found to be the most soluble of all the forms. 相似文献
36.
Several noncoding RNAs do vital cellular functions, including gene regulation and cell differentiation. Previously, we reported that vault RNA (vRNA) has the ability to recognize chemotherapeutic compounds, such as mitoxantrone, based on biophysical and biochemical analyses. In the present study, we show that human glioblastoma-, leukemia-, and osteocarcinoma-derived cell lines overexpress vRNA and exhibit higher resistance toward mitoxantrone. Interestingly, when vRNA expression was suppressed by RNA interference in these cells, the resistance progressively decreased. In agreement with these findings, overexpression of vRNA-1 caused resistance to mitoxantrone. These results suggest a role of vRNA in mitoxantrone resistance in malignant cells and justify further studies on the importance and application of noncoding RNAs in cancer chemotherapeutics. 相似文献
37.
Targeted deletion of AIF decreases mitochondrial oxidative phosphorylation and protects from obesity and diabetes 总被引:8,自引:0,他引:8
Pospisilik JA Knauf C Joza N Benit P Orthofer M Cani PD Ebersberger I Nakashima T Sarao R Neely G Esterbauer H Kozlov A Kahn CR Kroemer G Rustin P Burcelin R Penninger JM 《Cell》2007,131(3):476-491
Type-2 diabetes results from the development of insulin resistance and a concomitant impairment of insulin secretion. Recent studies place altered mitochondrial oxidative phosphorylation (OxPhos) as an underlying genetic element of insulin resistance. However, the causative or compensatory nature of these OxPhos changes has yet to be proven. Here, we show that muscle- and liver-specific AIF ablation in mice initiates a pattern of OxPhos deficiency closely mimicking that of human insulin resistance, and contrary to current expectations, results in increased glucose tolerance, reduced fat mass, and increased insulin sensitivity. These results are maintained upon high-fat feeding and in both genetic mosaic and ubiquitous OxPhos-deficient mutants. Importantly, the effects of AIF on glucose metabolism are acutely inducible and reversible. These findings establish that tissue-specific as well as global OxPhos defects in mice can counteract the development of insulin resistance, diabetes, and obesity. 相似文献
38.
Renu Bhardwaj Sukhbir Kaur Pramodh Kumar Nagar Hardesh Kumar Arora 《Plant Growth Regulation》2007,53(1):1-5
Brassinosteroids play an important role in growth and development of plants. They have been reported universally in all the
plants. The present study deals with the presence of these compounds in immature tea seeds. Five brassinosteroids, i.e. 6-deoxo-28-norcathasterone,
6-deoxo-28-norteasterone, 3-dehydro-6-deoxo-28-norteasterone, 6-deoxo-28-nortyphasterol and 6-deoxo-28-norcastasterone have
been isolated and identified by GC–MS. The identified brassinosteroids and their derivatives are active constituents of late
C-6 oxidation pathway, thereby suggesting the biosynthesis of brassinosteroids in tea seeds by late C-6 oxidation pathway. 相似文献
39.
In our search for synthetic substitutes for artemisinin and its derivatives we had earlier prepared a series of adamantane-based 1, 2, 4-trioxanes 5a-c which had shown promising activity against P. berghei in Swiss mice. We have further evaluated these and two new compounds (5d-e) against Plasmodium knowlesi W1, a virulent malaria parasite in rhesus monkeys, in the dose range of 40-80 mg/kg x 5 days by intramuscular route. Trioxanes 5b and 5c showed 100% protection and cure at 80 mg/kg x 5 days, while trioxane 5a showed 71% cure at this dose. Detailed studies again showed 50% curative effect of 5a at 40 mg/kg x 5 days treatment. 相似文献
40.
The rat glucocorticoid-induced receptor (rGIR) is an orphan G protein-coupled receptor awaiting pharmacological characterization. Among known receptors, rGIR exhibits highest sequence similarity to the neuropeptide Y (NPY)-Y(2) receptor (38-40%). The pharmacological profile of rGIR was investigated using (125)I-PYY(3-36), a Y(2)-preferring radioligand and several NPY analogs. rGIR displayed a similar displacement profile as reported for the Y(2) receptor, in that the Y(2)-selective C terminus fragments of NPY and PYY (NPY(3-36) and PYY(3-36)) showed high affinity binding and activation of rGIR (low nanomolar range). The rank order potency for displacement was NPY(3-36)>PYY(3-36)=NPY>NPY(13-36)>Ac, Leu NPY(24-36)>[D-Trp(32)]-NPY>Leu(31), Pro(34)-NPY=hPP. NPY and Y(2)-selective agonists NPY(3-36) and PYY(3-36) led to significant activation of (35)S-GTPgammaS binding to rGIR transfected cells. BIIE0246, a specific Y(2) antagonist, displaced (125)I-PYY(3-36) binding to rGIR with high affinity (95nM). Activation of (35)S-GTPgammaS binding by Y(2)-selective agonist in rGIR transfected cells was also completely abolished by BIIE0246. Our data report, for the first time, an interaction of NPY ligands with rGIR expressed in vitro, and indicate similarities between GIR and the NPY-Y(2) receptor. 相似文献