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891.
Viscosity, ultrasonic velocity and density measurements have been carried out for glycylglycine in aqueous FeCl3 solution as a function of molality at T=288.15 K, 298.15 K and 308.15 K. The experimental data have been used to derive properties such as isentropic compressibility
(κ
S
), change in isentropic compressibility (Δκ
S
), relative change in isentropic compressibility (Δκ
S
/κ
0), apparent molar compressibility, volume and their limiting apparent molar quantities along with the constants S
K
, S
V
and viscosity B-coefficient. The obtained thermodynamic properties have been discussed in terms of molecular interactions. 相似文献
892.
The densities, viscosities and ultrasonic velocities for glycylglycine–NiCl2 in aqueous ethanol mixtures have been studied in the temperature range 288.15–318.15 K. The excess molar volumes, viscosity deviations and changes in isentropic compressibility for the binary mixtures have been calculated and discussed in terms of hydrogen bonding and structure-breaking effect. The computed results are fitted to the Redlich–Kister polynomial. The results clearly indicate that there is a strong association in the mixtures studied. 相似文献
893.
We propose a non-supersymmetric SU(5) model in which only the third family of fermions are unified. The model remedies the non-unification of the three Standard Model couplings in non-supersymmetric SU(5). It also provides a mechanism for baryon number violation which is needed for the baryon asymmetry of the Universe and is not present in the Standard Model. Current experimental constraints on the leptoquark gauge bosons, mediating such baryon and lepton violating interactions in our model, allow their masses to be at the TeV scale. These can be searched for as a (bτ) or (tt) resonance at the Large Hadron Collider as predicted in our model. 相似文献
894.
Rakhi Grover Ritu Srivastava Omwati Rana A.K. Srivastava K.K. Maurya K.N. Sood D.S. Mehta M.N. Kamalasanan 《Journal of luminescence》2012,132(2):330-336
Hybrid organic–inorganic light emitting devices combine the color purity and durability of inorganic light emitting diodes (LEDs) with high efficiency, flexibility and low processing cost of organic LEDs (OLEDs). A significant challenge is to incorporate inorganic nanocrystals inside the OLED structure. In the present work, thin films of CdS were successfully incorporated inside standard OLED structure using vacuum thermal evaporation technique. For the characterization of these films, they were deposited on plain glass plates at room temperature and studied using structural (XRD and TEM), morphological (SEM and AFM) and optical (UV and PL) techniques. The films were found to be composed of nanocrystals of CdS in which the size of the crystals increased with the increase in film thickness. The hybrid organic–inorganic LEDs showed improved luminance and efficiency as compared to the organic LED without CdS layers. 相似文献
895.
Ultrafast nonlinear optical response of carbon nanotubes functionalized with water soluble porphyrin
Jyotsana Gupta C. Vijayan Sandeep Kumar Maurya D. Goswami 《Optics Communications》2012,285(7):1920-1924
A new nanocomposite is obtained by functionalizing carbon nanotubes (CNTs) with a water soluble metalloprophyrin using a simple chemical technique and characterized by optical absorption, IR, and Raman spectroscopy. Results from spectroscopic studies indicate the noncovalent nature of interaction between CNTs and porphyrin. The ultrafast nonlinear response is characterized by measuring the nonlinear absorption coefficient and refractive index by z-scan technique in the femtosecond pulse regime. The nanocomposite is found to exhibit two-photon absorption (TPA) with a reasonably large nonlinear optical coefficient, whereas pure CNTs is known to exhibit saturable absorption. Design of such water soluble nanocomposites offers scope for obtaining materials with enhanced ultrafast optical nonlinearity. 相似文献
896.
Dynamic viscoelastic moduli of an example polymerizing system namely the free radical bulk polymerization of methyl methacrylate (MMA), is studied using a Haake® rheometer–reactor assembly and an adapted Haake® HV-DIN cup-and-bob assembly. A series of experiments on the bulk polymerization of MMA under different temperature histories (isothermal, step-increase and step-decrease) and at two different initiator [2, 2′-azoisobutyronitrile (AIBN)] concentrations, have been carried out. The data on the storage modulus, G′, the loss modulus, G″, and the phase shift, δ, are measured during the course of polymerization, well into the gel effect region. A new correlation is developed for these properties. The kinetic model and the correlation for the zero-shear viscosity, presented in our earlier studies, are used in this generalized correlation. The correlation so developed is observed to represent experimental data quite well for a variety of temperature histories. The characteristic relaxation time, τi, representing the bulk polymerization of MMA is observed to be larger than the Rouse value, τR, by a factor of about seven. The findings are observed to be in agreement with several other studies for entangled non-polymerizing systems. 相似文献
897.
Lodsna Borkotoky Dr. Ram Awatar Maurya 《European journal of organic chemistry》2023,26(39):e202300822
Structurally diverse pyrroles were synthesized by direct coupling of α, β-unsaturated aldehydes and phenacyl azides. The scope of the synthetic method was successfully demonstrated by synthesizing 28 different phenyl(5-phenyl-1H-pyrrol-2-yl)methanones in high yields (87–95 %). Derivatization of a few synthesized pyrroles was demonstrated which shows the potential application of the developed protocol in new functional materials. To get a mechanistic insight of the reaction, a typical reaction was performed in a deuterated solvent and the progress of the reaction was monitored by recording its 1H NMR at regular time intervals. 相似文献
898.
Abdelghani Errehymy Sunil Kumar Maurya Sudan Hansraj Mohammed Daoud Haifa I. Alrebdi Abdel-Haleem Abdel-Aty 《Annalen der Physik》2023,535(8):2300178
Wormholes (WHs) are hypothetical topologically non-trivial spacetime structures that can be freely traversed by observers and connect two asymptotic regions or infinities. From the current theoretical development, the prospect of their existence is challenging but cannot be excluded. In this paper, generalized Ellis–Bronikov (GEB) traversable WH geometries for static and spherically symmetric spacetime in the background of gravity is explored. First, the Tsujikawa-like model and the shape function for the GEB model is considered, which depend on a sequence of simple Lorentzian WHs with two parameters: a free even integer exponent, n, besides the throat radius, r0. One also consider that these WHs are generated by dark matter galactic halos (DMGHs), based on the three most common phenomenological models, viz., Navarro–Frenk–White (NFW), Thomas–Fermi (TF), and pseudo-isothermal (PI). In this concern, the satisfaction of the energy conditions (ECs) which are dependent on the dark matter (DM) models, viz., dominant energy condition (DEC) and strong energy condition (SEC) and those which are not dependent viz., null energy condition (NEC) and WEC at the WH throat and its neighborhood is investigated. Finally, the presence of exotic matter is confirmed by the violation of the NEC in all cases, revealing the supremacy and physical acceptability to support the existence of the WHs and making them compatible and traversable in Tsujikawa's-like model. 相似文献
899.
Arnab Chakraborty Shambhavi Pandey Rishabh Kumar Pandey Khushwant Singh Saurabh Kumar Santosh Kumar T. Rajagopala Rao Neeladri Das 《应用有机金属化学》2023,37(1):e6917
A new di-platinum(II) organometallic compound ( 3 ) has been synthesized from a readily available pyrimidine derivative in two steps. 3 is a conformationally flexible molecule due to the presence of ethereal linkages. The application of 3 as an acceptor tecton in supramolecular chemistry was explored using coordination-driven self-assembly protocol. Thus, three neutral ( M 1 – M 3 ) and two ionic ( M 4 and M 5 ) metallomacrocycles were obtained in high yields, the structures of which included biologically active pyrimidine and π-conjugated trans-Pt(II)-alkynyl motifs. Formation of these five flexible [2 + 2] ensembles ( M 1 – M 5 ) was confirmed using FT-IR and NMR spectroscopy (1H, 31P{1H}, 13C{1H}, and 1H DOSY) as well as HRMS experiments. DFT calculations suggest that the macrocycles have nano-scalar dimensions with well-defined cavities. Cytotoxicity of 3 and macrocycles ( M 1 – M 5 ) were estimated against A549 human lung cancer cell line. Results indicate improvement in cytotoxicity upon self-assembly of 3 with neutral and ionic donor tectons to yield, respectively ionic and neutral macrocycles ( M 1 – M 5 ). Although the organometallic molecule 3 is almost seven times more potent than cisplatin, the antiproliferative potencies of the macrocycles ( M 1 – M 5 ) are up to 17 times better than cisplatin. Annexin V-FITC assay studies show that post-treatment with the organometallic 3 , or the macrocycles ( M 1 – M 5 ), the A549 cancer cells are present in the early apoptosis stage. 相似文献
900.
Dr. Inderpal Yadav Dr. Ved Prakash Ram R. Kaswan Prof. Dr. Mannar R. Maurya Prof. Dr. Muniappan Sankar 《欧洲无机化学杂志》2023,26(34):e202300459
Two new β-functionalized oxidomolybdenum(V) corroles, oxido[3-formyl-5,10,15-triphenylcorrolato]molybdenum(V) ( Mo-1 ) and oxido[3-dicyanovinyl-5,10,15-triphenylcorrolato]molybdenum(V) ( Mo-2 ) were synthesized and characterized by various spectroscopic techniques and electrochemical studies. Mo-2 manifests splitted B bands due to x and y polarizations and highly red shifted longest B and Q bands due to the electron-deficient nature of the dicyanovinyl group. EPR data showed that these complexes exhibit an axial compression with dxy1 configuration. DFT studies revealed that HOMO and LUMO orbitals are stabilized in Mo-2 relative to Mo-1 . Mo-1 exhibits two successive reversible reductions and two oxidation potentials in cyclic voltammetry. Surprisingly, Mo-2 exhibits three successive reversible reductions and two oxidations; the one extra reduction could possibly be due to the reduction of the dicyanovinyl moiety. The catalytic activities of Mo-1 and Mo-2 for the oxidative bromination of various phenols using H2O2-KBr-HClO4 mixture in water have been explored and exhibited excellent activity at a very low catalyst loading of 0.0030 and 0.0028 mol%, respectively. Both synthesized β-functionalized Mo(V) corroles manifest much higher conversion and TOF (59801–71174 h−1) for oxidative bromination of phenols relative to earlier reported meso-functionalized Mo(V) corroles (20781–61646 h−1). Hence, Mo-1 and Mo-2 mimic vanadium bromoperoxidase (VBPO) and act as functional models for these catalytic applications. These catalysts were reused upto 3 cycles and showed conversion rate upto 82 % indicating their excellent thermal and chemical stabilities. 相似文献