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181.
Choi EY Park K Yang CM Kim H Son JH Lee SW Lee YH Min D Kwon YU 《Chemistry (Weinheim an der Bergstrasse, Germany)》2004,10(21):5535-5540
In this paper, we report two metal-organic frameworks [Co3(ndc)3(bipyen)(1.5)]H2O (1) and [Co2(ndc)2bipyen)]C6H6.H2O (2) (bipyen=trans-1,2-bis(4-pyridyl)ethylene, H2ndc=2,6-naphthalenedicarboxylic acid). These compounds were both synthesized from identical hydrothermal reaction conditions except that benzene was added to the reaction for 2. Crystal structures show that the two compounds have triply interpenetrated three-dimensional frameworks and these frameworks have the same primary structure of a two-dimensional network of interconnected [Co2(O2CR)(4/2)] (R=naphthalene group) paddle-wheels and bridging bipyen ligands. Both compounds have guest water molecules and, in addition, 2 has guest benzene molecules. Structural transformations of the host accompanied guest removal, which can be monitored by powder X-ray diffraction. N2 adsorption data of 2 show that there are two different types of pores corresponding to the benzene and water pores. Upon exposure to vapors of several organic molecules, the heat-treated sample of 2 adsorbs benzene and cyclohexene, but does not adsorb toluene, (o-, m-, and p-)xylenes, cycloheptatriene, or cyclohexane. 相似文献
182.
Yun‐Gon Kim Geun‐Cheol Gil Kyung‐Soon Jang Sukmook Lee Hyoung‐Il Kim Jung‐Sik Kim Junho Chung Chung‐Gyu Park David J. Harvey Byung‐Gee Kim 《Journal of mass spectrometry : JMS》2009,44(7):1087-1104
N‐glycan structures released from miniature pig endothelial and islet cells were determined by matrix‐assisted laser desorption/ionization time‐of‐flight (MALDI‐TOF), negative ion electrospray ionization (ESI) MS/MS and normal‐phase high performance liquid chromatography (NP‐HPLC) combined with exoglycosidase digestion. Totally, the identified structures were 181 N‐glycans including 129 sialylated and 18 α‐galactosylated glycans from pig endothelial cells and 80 N‐glycans including 41 sialylated and one α‐galactosylated glycans from pig islet cells. The quantity of the α‐galactosylated glycans from pig islet cells was certainly neglectable compared to pig endothelial cells. A number of NeuGc‐terminated N‐glycans (80 from pig endothelial cells and 13 from pig islet cells) are newly detected by our mass spectrometric strategies. The detailed structural information will be a matter of great interest in organ or cell xenotransplantation using α 1,3‐galactosyltransferase gene‐knockout (GalT‐KO) pig. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
183.
Chung IW Kwon SJ Kim SJ Jang ES Hwang SJ Choy JH 《The journal of physical chemistry. B》2006,110(33):16197-16200
A coordination compound of HgI(2)(pyridine)(2) can be successfully intercalated into a single crystalline Bi(2)Sr(2)CaCu(2)O(y) high-T(c) superconductor through an interlayer complexation reaction between pyridine molecules and bismuth cuprate pre-intercalated with mercuric iodide. X-ray diffraction and X-ray absorption spectroscopic results clearly demonstrate that the single crystalline nature of the pristine bismuth cuprate remains unchanged even after the intercalation of organic complex as well as those of iodine and mercuric iodide. According to the angle-dependent dc magnetization measurements, the intercalation of bulky organic molecules completely blocks superconductive currents along the c-axis, whereas a superconducting transition along the in-plane direction still occurs in the organic intercalate. In the case of the iodine or mercuric iodide intercalates with smaller lattice expansions, an out-of-plane diamagnetic transition is not wholly quenched but significantly depressed by the intercalation, confirming the reduction of interlayer interaction. The present finding can provide straightforward evidence of the two-dimensionality of high temperature superconductivity in the present cuprate-based nanohybrid material. 相似文献
184.
The approximate rates and stoichiometry of the reaction of lithium tri(2-methyl-2-propanethioxy)aluminum hydride (LTBSA) with selected organic compounds containing representative functional groups under the standardized conditions (tetrahydrofuran, 0 °C) were studied in order to define the reducing ability of LTBSA also compared with those of the parent lithium aluminum hydride (LAH) and lithium t-butoxyaluminum hydride (LTBA). 相似文献
185.
Won Suk Shin Sung Chul Kim Seung‐Joon Lee Han‐Su Jeon Mi‐Kyoung Kim B. Vijaya Kumar Naidu Sung‐Ho Jin Jin‐Kook Lee Jae Wook Lee Yeong‐Soon Gal 《Journal of polymer science. Part A, Polymer chemistry》2007,45(8):1394-1402
We synthesized a novel low‐band‐gap, conjugated polymer, poly[4,7‐bis(3′,3′‐diheptyl‐3,4‐propylenedioxythienyl)‐2,1,3‐benzothiadiazole] [poly(heptyl4‐PTBT)], consisting of alternating electron‐rich, diheptyl‐substituted propylene dioxythiophene and electron‐deficient 2,1,3‐benzothiadiazole units, and its photovoltaic properties were investigated. A thin film of poly(heptyl4‐PTBT) exhibited an optical band gap of 1.55 eV. A bulk‐heterojunction solar cell with indium tin oxide/poly(3,4‐ethylenedioxythiophene)/poly(heptyl4‐PTBT): methanofullerene [6,6]‐phenyl‐C61‐butyric acid methyl ester (PCBM) (1:4)/LiF/Al was fabricated with poly(heptyl4‐PTBT) as an electron donor and PCBM as an electron acceptor and showed an open‐circuit voltage, short‐circuit current density, and power conversion efficiency of 0.37 V, 3.15 mA/cm2, and 0.35% under air mass 1.5 (AM1.5G) illumination (100 mW/cm2), respectively. A solid‐state, dye‐sensitized solar cell with a SnO2:F/TiO2/N3 dye/poly(heptyl4‐PTBT)/Pt device was fabricated with poly(heptyl4‐PTBT) as a hole‐transport material. This device exhibited a high power conversion efficiency of 3.1%, which is the highest power conversion efficiency value with hole‐transport materials in dye‐sensitized solar cells to date. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 1394–1402, 2007 相似文献
186.
187.
Formation constants for the 1:1 complexation equilibrium reactions between β-cyclodextrin and the drugs, clonazepam, delorazepam, diazepam (Valium), flurazepam (Dalmane), lorazepam, medazepam, nitrazepam, nordiazepam, oxazepam, and temazepam, were measured by using circular dichroism spectropolarimetry. The range in values is almost one order of magnitude, suggesting a strong structural dependence in the interlocking between the host and different guests. Enthalpy and entropy data for the lorazepam interaction are consistent with data from several earlier studies. Direct determinations of diazepam and flurazepamm in pharmaceutical products are within ±2% of the prescribed amounts. 相似文献
188.
Zirconia is known to be one of the best materials for the chromatographic support due to its excellent chemical, thermal, and mechanical stability. In this work, we report preparation and use of 9-O-(phenyloxycarbonyl)quinine-bonded carbon-clad zirconia (QNCZ) as a chiral stationary phase (CSP) for separation of N-(2,4-dinitrophenyl) (DNP)-amino acids (AAs) enantiomers in reversed-phase liquid chromatography. Retention and enantioselectivity of the QNCZ CSP were compared with those of quinine 3-triethoxysilylpropylcarbamate-coated zirconia (QNZ) and quinine 3-triethoxysilylpropylcarbamate-bonded silica (QNS). The QNCZ CSP showed in general the better enantioselectivity for most of the amino acids studied. 相似文献
189.
Kim WS Kim J Park JK Mukamel S Rhee SK Choi YK Lee JY 《The journal of physical chemistry. B》2005,109(7):2686-2692
We investigate the structures, NMR chemical shifts, absorption spectra, frontier molecular orbitals, and transition density matrices of pi-stacked polyfluorenes by ab initio calculations. For F1-F4, we consider two different conformations, syn and anti. The simulated 1H NMR chemical shifts are in good agreement with the previous experiment, and the significantly upfielded chemical shifts explain that the fluorene moieties are stacked on each other. It is found that the relative stability for syn and anti conformers is almost equivalent in B3LYP calculations; however, the syn conformer becomes much more stable than the anti conformer in MP2 calculations, which is consistent with the experimental finding that only the syn conformers are relevant. The vertical detachment energy, which is linearly proportional to the ionization potential, shows the same size dependence as the previous experiment. The electron attachment energy decreases exponentially as the size increases, which implies that the electron transport would be possible even for long chains such as F3 and F4. This was evident from the frontier molecular orbitals (HOMO and LUMO). Also, it is found that the syn conformers are very favorable for electron transport through the pi-stacked fluorene moieties. 相似文献
190.
Single-stage anaerobic codigestion for mixture wastes of simulated Korean food waste and waste activated sludge 总被引:2,自引:0,他引:2
Nam Hyo Heo Soon Chul Park Jin Suk Lee Ho Kang Don Hee Park 《Applied biochemistry and biotechnology》2003,107(1-3):567-579
Korean food waste was treated with a single-stage anaerobic codigester (SSAD) using waste activated sludge (WAS) generated
from a municipal wastewater treatment plant. The stability and performance of the system was analyzed. The C/N ratio was improved
with increasing food waste fraction of feed mixture. The pH, alkalinity, and free ammonia nitrogen concentration were the
parameters used to evaluate the digester’s stability. The experimentally determined values of the parameters indicated that
there were no methane inhibitions in the digester. Digester performance was determined by measuring the total chemical oxygen
demand TCOD), volate solids (VS) removal, methane content in biogas, methane production rate (MPR), and specific methane productivity.
Methane content in biogas and MPR were significantly dependent on hydraulic retention time (HRT) and ratio of food waste to
WAS. The methane content in biogas decreased at shorter HRT or higher organic loading rate (OLR) with increased food waste
fraction. Concerning the performance of the codigester, the optimum operating condition of the SSAD was found to be at an
HRT of 10 d with a feed mixture ratio of 50% food waste and 50% WAS. A TCOD removal efficiency of 53.6% and a VS removal efficiency
of 53.7% were obtained at an OLR of 5.96 kg of TCOD/(m3·d) and 3.14 kg of VS/(m3·d), respectively. A maximum MPR of 1.15 m3 CH4/(m3·d) and an SMP of 0.37 m3 CH4/kg of VSfeed were obtained at an HRT of 10 d with a methane content of 63%. 相似文献