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31.
McKeown NB Hanif S Msayib K Tattershall CE Budd PM 《Chemical communications (Cambridge, England)》2002,(23):2782-2783
Network polymers exhibiting large surfaces areas (900-1000 m2g-1) are prepared by the highly efficient dibenzodioxane forming reaction between meso-tetrakis(pentafluorophenyl)porphyrin and a rigid bis(catechol) monomer. 相似文献
32.
A finite algorithm is presented in this study for solving Bilinear programs. This is accomplished by developing a suitable cutting plane which deletes at least a face of a polyhedral set. At an extreme point, a polar cut using negative edge extensions is used. At other points, disjunctive cuts are adopted. Computational experience on test problems in the literature is provided.This paper is based upon work supported by the National Science Foundation under Grant No. ENG-77-23683. 相似文献
33.
Liu L Qiu S Wang B Zhang W Lu P Xie Z Hanif M Ma Y Shen J 《The journal of physical chemistry. B》2005,109(49):23366-23370
We have investigated the thermal degradation in air by Fourier transform infrared spectroscopy of a ladder-type copolymer containing fluorene units in the backbone (Me-LPF), to reveal the formation of the ketonic defects. As thermal treatment of Me-LPF film at 200 degrees C in air proceeds, a new group of complex absorption bands due to degradation products arises in the range between 1800 and 1600 cm(-1). The observed overlapping bands were separated and assigned by utilizing the second-derivative IR spectral analysis, which can narrow the peak width to one-third of the originals and thereby eases the analysis. The degraded products were assigned as fluorenone (1718 cm(-1)) and benzophenone (Ar-(C=O)-Ar) (1665 cm(-1)), formed by the oxidation of the backbone, and acylphenone (Ar-(C=O)-R) (1685 cm(-1)) from the side chain. The fluorenone was found to be the major component among the degraded products in the main chain, and the time and temperature dependence indicated that the oxidation is a kind of autocatalytic radical-chain process. The oxidation can reach a very high degree (approximately 30% for 6 h oxidation at 240 degrees C estimated by absorption of the alkyl). Our results suggest the possibility of the oxidation of the 9-bialkylfluorene sites. We propose that the degradation of the alkyl in the side chain can help the radicals to propagate in the chain reaction. 相似文献
34.
35.
M. Hussain M. Hanif S. Ali S. Shahzadi M. S. Ahmad B. Mirza H. S. Evans 《Journal of the Iranian Chemical Society》2010,7(1):155-163
New organotin(IV) compounds containing the carboxylate ligand 2,3-methylenedioxybenzoic acid (HL) have been synthesized with the general formula R2SnL2 (R = Me, Et, n-Bu, Ph and n-Oct) and R3SnL (R = n-Bu). All compounds have been studied in the solution state by multinuclear NMR (1H, 13C and 119Sn) by using the non-coordinating solvent and also in solid sate by FTIR, mass spectrometry and X-ray crystallography. Spectroscopic data have shown that methylenedioxy moiety does not coordinate with tin atom and the coordination site is actually -COO group, as is proved by X-ray structure determination. The solid state structure of compound (2) has been determined by X-ray crystallography which shows that the complex (2) has distorted octahedral geometry. These complexes have been evaluated in vitro against crown gall tumor and antibacterial activity. Interesting results were noticed during the bio-activity screenings, which proved their in vitro biological potential and possible use as drugs. 相似文献
36.
Anderson MW Holmes SM Hanif N Cundy CS 《Angewandte Chemie (International ed. in English)》2000,39(15):2707-2710
37.
Chunxiang Hu Yunyun He Shuiliang Chen Yongmei Zhu Muddasir Hanif Haoqing Hou 《Journal of Solid State Electrochemistry》2014,18(10):2797-2802
A binder-free activated carbon paper (ACP) was simply prepared for electric double-layer capacitors by the carbonization of filter paper, followed by heat-air activation at a lower temperature. The electrochemical cells assembled using the as-prepared ACP-470 provides a high specific capacitance of 296.4 F g?1 at current density of 0.5 A g?1 and a high rate performance at a current density of 150 A g?1 with a capacitance of 191.2 F g?1 and a high cycle ability at 10,000 recycles with 100 % capacitance retention. In addition, the ACP has a lower electrical resistivity and provides an effective energy storage performance with a maximum energy density of 41.2 Wh kg?1 and a maximum power density of 138.0 kW kg?1 in a voltage range of 1 V. 相似文献
38.
Muhammad Asif Hanif Ahmed Yahya Al-Maskari Jamal Nasser Al-Sabahi Ibtisam Al-Hdhrami Muhammad Mumtaz Khan Ahlam Al-Azkawi 《Natural product research》2015,29(24):2332-2335
Medicago sativa Linn growing in Omani desert were chemically characterised using flame photometry, inductively coupled plasma, gas chromatography–mass spectrometry and high performance liquid chromatographic (HPLC) analysis. HPLC analyses were performed to determine the phenolics and flavonoids present in M. sativa. The major compounds detected in M. sativa leaves were protchaechenic acid (3.22%), hydroxyl benzoic acid (1.05%), β-Phenyl caffate (0.97%) and kaempherol (0.89%). Pterostilbene, a cholesterol-lowering compound, was detected in M. sativa. 相似文献
39.
Muhammad Hanif Mukhtiar Hussain Moazzam H. Bhatti Saqib Ali Helen S. Evans 《Structural chemistry》2008,19(5):777-784
Four new complexes, [Ph3Sn(isopropylACDA)] (1), [Ph2SnCl(isopropylACDA)] (2), [Ph3Sn(secbutylACDA)] (3), and [Ph2SnCl(secbutylACDA)] (4), have been prepared from reaction between N-alkylated 2-amino-1-cyclopentene-1-carbodithioic acids (ACDA) with Ph2SnCl2 and Ph3SnCl in 1:1 ratio. All complexes are characterized by FTIR, multinuclear NMR (1H, 13C, and 119Sn) and mass spectrometry. In all complexes, the S–H proton has been removed and coordination takes place through the carbodithioate
moiety. The 119Sn NMR data are consistent with five coordination of tin atom in solution. Complexes 2, 3, and 4 have also been confirmed by single X-ray crystallography. All three crystals are triclinic with space group P − 1. In complexes 2 and 4, the geometry around tin atom is distorted trigonal bipyramidal while in 3 the geometry is in between distorted tetrahedral and trigonal bipyramid. In all three structures, ligands are asymmetrically
coordinated to tin atom. In addition, crystal structures are further stabilized by N–H···S hydrogen bonding. 相似文献
40.
Bing Yang Dr. Soo‐Kang Kim Hai Xu Young‐Il Park Houyu Zhang Dr. Cheng Gu Fangzhong Shen Dr. Chunlei Wang Dandan Liu Xiaodong Liu Prof. Muddasir Hanif Shi Tang Weijun Li Feng Li Dr. Jiacong Shen Prof. Jong‐Wook Park Prof. Yuguang Ma Prof. 《Chemphyschem》2008,9(17):2601-2609
Herein, we describe the molecular electronic structure, optical, and charge‐transport properties of anthracene derivatives computationally using density functional theory to understand the factors responsible for the improved efficiency and stability of organic light‐emitting diodes (OLEDs) with triphenylamine (TPA)‐substituted anthracene derivatives. The high performance of OLEDs with TPA‐substituted anthracene is revealed to derive from three original features in comparison with aryl‐substituted anthracene derivatives: 1) the HOMO and LUMO are localized separately on TPA and anthracene moieties, respectively, which leads to better stability of the OLEDs due to the more stable cation of TPA under a hole majority‐carrier environment; 2) the more balanceable hole and electron transport together with the easier hole injection leads to a larger rate of hole–electron recombination, which corresponds to the higher electroluminescence efficiency; and 3) the increasing reorganization energy for both hole and electron transport and the higher HOMO energy level provide a stable potential well for hole trapping, and then trapped holes induce a built‐in electric field to prompt the balance of charge‐carrier injection. 相似文献