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51.
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Udai P. Singh Preeti Babbar Pooja Tyagi Thomas Weyhermüller 《Transition Metal Chemistry》2008,33(8):931-940
A novel Co(II) hydroxo complex Co{HB(3-tBu-5-iPrpz)3}(OH) 4 {where HB(3-tBu-5-iPrpz)3 = hydrotris(3-tert-butyl-5-isopropylpyrazol-l-yl)borate} has been prepared and its molecular structure has been determined by X-ray crystallography.
This complex is mononuclear with distorted tetrahedral geometry. The reaction of CO2 with Co{HB(3-tBu-5-iPrpz)3}(OH) resulted in the formation of a μ-carbonato bridged binuclear complex [Co{HB(3-tBu-5-iPrpz)3}]2(CO3) wherein the carbonate group is bound to both metal centers in an asymmetrical manner. In order to explore the role of labile
metal complexes in promoting ester hydrolysis, complexes [Co{HB(3,5-iPr2pz)3}]2(OH)2 and Co{HB(3-tBu-5-iPrpz)3}(OH) have been used as catalysts in the hydrolysis of both carboxylate as well as phosphate esters. The product of 4-nitrophenylacetate
hydrolysis with Co{HB(3-tBu-5-iPrpz)3}(OH) was isolated as four coordinate Co{HB(3-tBu-5-iPrpz)3}(OC6H4-4-NO2) 6, whereas the reaction of 4-nitrophenyltrifluoroacetate with [Co{HB(3,5-iPr2pz)3}]2(OH)2 resulted the formation of the six coordinate Co{HB(3,5-iPr2pz)3}(OC6H4-4-NO2)(MeCN)2 species.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.
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Udai P. SinghEmail: |
53.
In this issue of Chemistry & Biology, Kinjo et al. (2008) propose that the addition of oligosaccharides to the core outer membrane glycosphingolipid in Sphingomonas spp. may be an adaptation that allows bacteria to evade recognition by Natural Killer T cells, thus suggesting a remarkable process of host/pathogen coevolution. 相似文献
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Shivangi Srivastava Rajesh K. Yadav Poorn Prakash Pande Satyam Singh Surabhi Chaubey Pooja Singh Sarvesh Kumar Gupta Shivani Gupta Tae Wu Kim Dhanesh Tiwary 《Photochemistry and photobiology》2023,99(4):1097-1105
Photocatalytic processes triggered by graphene-based photocatalysts under solar light have sparked interest as a new sort of instrument for solar chemical synthesis. Herein we investigated self-assembled graphene quantum dots (GQDs)/NiSe-NiO composite photocatalyst for organic transformation as well as dye degradation. The synthesized GQDs/NiSe-NiO composite photocatalyst has an excellent suitable band gap, high molar extinction coefficient, low toxicity and chemical/thermal stability. The GQDs/NiSe-NiO composite photocatalyst emerges as a new standard for sulfur oxidation and dye degradation reactions under homemade LED light with high yield. 相似文献
55.
Smriti Moi Shamasoddin Shekh K. Kasi Amarnath Reddy Pooja Dhurjad Rajesh Sonti Konkallu Hanumae Gowd 《Photochemistry and photobiology》2023,99(3):911-919
Photostabilizers have been used to impart stability to an FDA-approved chemical UV-A filter avobenzone against the UV-A radiations and sunlight. The thiol group of glutathione plays a critical role in imparting the photostabilization activity of glutathione on avobenzone. The current report aims to evaluate the photostabilization activity of multiple thiols containing cysteine peptides on avobenzone. Cysteine-tripeptide and cysteine-pentapeptide were chemically synthesized and characterized using mass spectrometry. Synthetic peptides were assessed for their photostabilization activity on the enolic-form of the avobenzone under natural sunlight using UV spectroscopy in both protic and aprotic solvents. Unlike glutathione, which has pronounced activity in protic solvents, cysteine-pentapeptide exhibits similar photoprotection activity in both protic and aprotic solvents. Computational calculations using DFT suggest that peptide cysteine thiols may assist in the reversal of the photoketonization process of avobenzone thereby exhibiting the photoprotection activity to the enolic-form of avobenzone. Peptide cysteine thiols lower the activation energy barrier of keto-to-enol tautomerization of avobenzone by 30 kcal mol−1 by assisting the proton shuttle through a six-membered transition state. The current report emphasizes the applications of peptide thiols in cosmetics and may help in the development of peptides as aesthetic medicines. 相似文献
56.
Umeshkanta Singh Thounaojam Pooja Rani Sharma Manish Dev Shrimali 《The European physical journal. Special topics》2016,225(1):17-27
A system of Hindmarsh-Rose relay neurons with time delay coupling is considered in which the relay (central) neuron has an additional feedback term that represents the interaction activity with a local environment. The strength of environmental coupling with the central neuron plays an important role in inducing synchronization and de-synchronization between the outer neurons. The strength of feedback developed from the environmental coupling has created a gradual quenching in the oscillations of the central neuron. At a higher feedback coupling strength, oscillation of the central neuron is suppressed drastically and a transition from a regime of synchronization to out-of-phase synchronization take place between the oscillations of the two outer neurons. 相似文献
57.
Noa?Cohen Pooja?SabhachandaniView authors OrcID profile Saheli?Sarkar Lindy?Kahanovitz Norman?Lautsch Steven?J.?Russell Tania?KonryEmail author 《Mikrochimica acta》2017,184(3):835-841
This paper describes a miniaturized microsphere-based immunoassay integrated into a microfluidic device for rapid quantitation of insulin. Analysis of bionic pancreas studies have revealed that the rates of absorption of insulin analogs vary from patient to patient, and even within patients on different occasions. Thus development of an approach to monitor insulin continuously allows the pharmacokinetic characteristics of insulin analogs to be determined in real-time. The authors have developed a microsphere-based continuous flow assay in a microfluidic chip that allows for the detection of insulin within seconds with high sensitivity and specificity. The method was applied to near real-time monitoring of clinical samples. Calibration plot were established for different insulin analogs such as insulin aspart (Novolog), insulin lispro (Humalog), and regular human insulin (RHI) and the insulin detection limit was 0.26 ng.mL?1 (44 pM). This sensitivity allows to detect the fasting insulin levels of T1D patients, which are reported in the range of 50–180 pM (0.3–1 ng.mL?1), after treatment with subcutaneous insulin administration. This fast approach was also applied to sera collected in intervals from T1D patients after a bolus of insulin aspart delivery. The insulin profile obtained by this method is similar to the basal and peak insulin levels as determined using the standard non-continuous ELISA reference method. In our perception, this assay will improve healthcare by personalizing diagnostics for better clinical outcome and provide real-time feedback on sensing and actuation. 相似文献
58.
Dai X Choi SB Braun CW Vaidya P Kilina S Ugrinov A Schulz DL Boudjouk P 《Inorganic chemistry》2011,50(9):4047-4053
The addition of halide anions (X' = Cl(-), Br(-), or I(-)) to perhalocyclohexasilane Si(6)X(12) (X = Cl or Br) led to the formation of complexes comprising [Si(6)X(12)X'(2)](2-) dianions. An upfield shift in the (29)Si NMR spectra was noted upon coordination, and structural determination by X-ray crystallography showed that the dianions adopt an "inverse sandwich" structure where the six cyclic silicon atoms form a planar hexagon with the two halide anions X' located on the 6-fold axis equally disposed above and below the plane of the Si(6) ring. Additionally, these apical X' atoms are within the van der Waals bonding distance to the silicon ring atoms, indicating a strong interaction between X' and silicon atoms. These results detail crystallographic variations within the halogen series providing further insight into the nature of the Lewis acid sites above and below the Si(6)X(12) ring, where interactions with hard Lewis bases such as halide anions are observed. Interestingly, the stereochemistry of the silicon atoms in [Si(6)X(12)X'(2)](2-) is not affected much by the size or electronegativity of the halogen atoms. 相似文献
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Adsorption of Fe, Co and Ni atoms on a hybrid hexagonal sheet of graphene and boron nitride is studied using density functional methods. Most favorable adsorption sites for these adatoms are identified for different widths of the graphene and boron nitride regions. Electronic structure and magnetic properties of the TM-adsorbed sheets are then studied in detail. The TM atoms change the electronic structure of the sheet significantly, and the resulting system can be a magnetic semiconductor, semi-metal, or a non-magnetic semiconductor depending on the TM chosen. This gives tunability of properties which can be useful in novel electronics applications. Finally, barriers for diffusion of the adatoms on the sheet are calculated, and their tendency to agglomerate on the sheet is estimated. 相似文献