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241.
A Ne atom exposed to a strong ultrashort magnetic field of the order of 109 G that lasts for a few femtoseconds is investigated through a current-density functional theory (CDFT) based approach employing a vector exchange–correlation potential that depends on the electronic charge-density as well as on the current-density of the atom. The CDFT based approach yields time-dependent electronic charge- and current-density, along with the exchange–correlation potential and energy, significantly different from that obtained using a current-density independent approach, in particular, at the field-strengths >109 G. 相似文献
242.
In the present research work, four new 14-membered tetraazamacrocylic complexes of Cobalt(II), Nickel(II), Copper(II) and Zinc(II) with (1E,14E)-8,8,17,17-tetramethyl-2,5,11,14-tetraazatricyclo[13.3.1.16,10]icosa-1,5,10,14-tetraene were synthesized using the template methodology that leads to the formation of a complex of type [MLX2] in which L is a macrocyclic ligand derived from ethylenediamine (ED) and 5,5-dimethylcyclohexanedione (DCH) and X = Cl−/CH3COO−. Spectroscopic, physical, and analytical characterization of complexes was carried out with the assistance of infra-red, nuclear magnetic resonance, electron spin resonance, Ultraviolet-visible, powder X-Ray diffraction, electron spray ionization - mass spectroscopy (ESI-MS), thermogravimetric analysis, magnetic susceptibilities, and carbon hydrogen nitrogen analysis. The information regarding the monomeric and nonelectrolytic behavior was elucidated from ESI-MS and molar conductance values. Powder X-Ray diffractogram studies point toward the crystalline or amorphous nature of the complexes. All the compounds exhibited the nonelectrolytic nature. Semiempirical calculations were performed using Gaussian 09 software and quantum chemical parameters were determined. Newly designed macrocyclic complexes were examined for their antifungal and antibacterial potency by the Agar well diffusion method. In-vitro DNA binding studies were carried out in order to understand the extent and nature of binding shown by the complexes with the DNA. In addition to this, in-silico absorption distribution metabolism excretion toxicity studies were also carried out for the interpretation of drug-like properties in the newly synthesized complexes. 相似文献
243.
Synthesis of isodamascone and its analogs, the commercially important aroma compounds, have been accomplished from the readily available 1,5,5‐trimethyl‐2‐cyclohexen‐1‐ol via a short, facile, and simple sequence of reactions in excellent yield. 相似文献
244.
K. Penta Rao Ashok K. BasakAmancha Raju Vikas S. PatilL. Krishnakanth Reddy 《Tetrahedron letters》2013
An efficient aminocarbonylation of N-tosylhydrazones derived from aromatic aldehydes and ketones mediated by molybdenum hexacarbonyl is reported. This method is palladium-free and provides a rapid access to the α-aryl acetamides in moderate to good yields. 相似文献
245.
Palladium‐Catalyzed Regio‐ and Stereoselective Cross‐Addition of Terminal Alkynes to Ynol Ethers and Synthesis of 1,4‐Enyn‐3‐ones 下载免费PDF全文
Madala Hari Babu Vikas Dwivedi Ruchir Kant Dr. Maddi Sridhar Reddy 《Angewandte Chemie (International ed. in English)》2015,54(12):3783-3786
Conjugated enynes, enol ethers, and enynones are versatile building blocks that can be elaborated by a wide variety of synthetic transformations. The selective synthesis of such units is a prerequisite for their effective utilization. The synthesis of conjugated 2‐phenoxyenynes through a palladium‐catalyzed cross‐addition of terminal alkynes to phenylethynyl ethers (hydroalkynylation) is now presented. The reaction is highly regio‐, stereo‐, and chemoselective, and shows excellent tolerance toward functional groups. The addition further features very mild reaction conditions (room temperature) and an inexpensive catalytic system (without a ligand and with a cheaply available Pd catalyst). The thus synthesized enynyl ethers with allylic hydroxy tethers, which survived the reaction, were shown to be ready precursors for valuable 1‐en‐4‐yn‐3‐ones. 相似文献
246.
Effect of head group polarity and spacer chain length on the aggregation properties of gemini surfactants in an aquatic environment 总被引:2,自引:0,他引:2
Borse M Sharma V Aswal VK Goyal PS Devi S 《Journal of colloid and interface science》2005,284(1):282-288
The aggregation behavior of cationic gemini surfactants with respect to variation in head group polarity and spacer length is studied through conductance, surface tension, viscosity, and small-angle neutron-scattering (SANS) measurements. The critical micellar concentration (cmc), average degree of micelle ionization (beta(ave)), minimum area per molecule of surfactant at the air-water interface (A(min)), surface excess concentration (gamma(max)), and Gibb's free energy of micellization (delta G(mic)) of the surfactants were determined from conductance and surface tension data. The aggregation numbers (N), dimensions of micelles (b/a), effective fractional charge per monomer (alpha), and hydration of micelles (h(E)) were determined from SANS and viscosity data, respectively. The increasing head group polarity of gemini surfactant with spacer chain length of 4 methylene units promotes micellar growth, leading to a decrease in cmc, beta(ave), and delta G(mic) and an increase in N and b/a. This is well supported by the observed increase in hydration (h(E)) of micelles with increase in aggregation number (N) and dimension (b/a) of micelle. 相似文献
247.
Sims RA Roth ZA Willis CC Kadwani P McComb TS Shah L Sudesh V Poutous M Johnson EG Richardson M 《Optics letters》2011,36(5):737-739
We used guided-mode resonance filters (GMRFs), fabricated using thin-film deposition and chemical etching, as intracavity feedback elements to stabilize and narrow the output spectrum in thulium-doped fiber oscillators operating in the 2?μm wavelength regime, producing linewidths of <700?pm up to 10?W power levels. A Tm fiber-based amplified spontaneous emission source was used to characterize the reflective properties of the GMRFs. Linewidths of 500?pm and a 7.3?dB reduction in transmission were measured on resonances. 相似文献
248.
Srivastava S Awasthi R Gajbhiye NS Agarwal V Singh A Yadav A Gupta RK 《Journal of colloid and interface science》2011,359(1):104-111
In this study, we describe the development of a facile and effective route for the synthesis of Fe(3)O(4)-based T(1) contrast agent, which can be useful for in vivo magnetic resonance (MR) imaging. Citrate-coated Fe(3)O(4) nanoparticles (6 nm) with a narrow size distribution were synthesized by "one-pot green chemistry route" in diethylene glycol (DEG) solvent. The synthesized nanoparticles were characterized by different analytical techniques including XRD, TEM, HRTEM, and FTIR. At room temperature, nanoparticles exhibited superparamagnetic nature with high saturation magnetization. The longitudinal (r(1)) and transverse (r(2)) relaxivities were found to be 35.45 and 51.81 mM(-1)s(-1), respectively. Contrast agent developed by this method showed a relatively higher longitudinal relaxivity (r(1)) and the lowest relaxivity ratio (r(2)/r(1)=1.46) at 3T MR field. The anionic nature of citric acid facilitated non-specific internalization without impairment of cell viability and functionality. The in vitro studies showed both phagocitic and non-phagocytic uptake of these NPs. In vivo MR imaging of swine showed both T(1) and T(2) contrast effect. 相似文献
249.
In this study, we have investigated the stability and conductivity of unsupported, two-dimensional infinite gold nanowires
using ab initio density functional theory (DFT). Two-dimensional ribbon-like nanowires with 1–5 rows of gold atoms in the
non-periodic direction and with different possible structures have been considered. The nanowires with >2 rows of atoms exhibit
dimerization, similar to finite wires, along the non-periodic direction. Our results show that in these zero thickness nanowires,
the parallelogram motif is the most stable. A comparison between parallelogram- and rectangular-shaped nanowires of increasing
width indicates that zero thickness (111) oriented wires have a higher stability over (100). A detailed analysis of the electronic
structure, reveals that the (111) oriented structures show increased delocalization of s and p electrons in addition to a stronger delocalization of the d electrons and hence are the most stable. The density of states show that the nanowires are metallic and conducting except
for the double zigzag structure, which is semiconducting. Conductance calculations show transmission for a wide range of energies
in all the stable nanowires with more than two rows of atoms. The conductance channels are not purely s and have strong contributions from the d levels, and weak contributions from the p levels. 相似文献
250.
Magnetic CuFe2O4 nanoparticles: a retrievable catalyst for oxidative amidation of aldehydes with amine hydrochloride salts 总被引:1,自引:0,他引:1
The application of magnetic CuFe2O4 nanoparticles for the oxidative amidation of aldehydes with amine hydrochloride salts is described. A wide range of amides have been synthesized in good to excellent yields under mild conditions. Chiral amide also synthesized from its corresponding chiral amine salt with retention of the stereochemistry. In particular, the performance of the magnetic separation of the catalyst was very efficient and an alternative to time, solvent and energy-consuming separation procedures. The catalytic activity of the catalyst remains unaltered after five consecutive cycles, making it environmentally benign and widely applicable due to its efficiency, ease of handling and cost effectiveness. 相似文献