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71.
Matsuno T Karo M Sasahara H Watanabe T Inaba M Takahashi M Yaguchi SI Yoshioka K Sakato M Kawashima S 《Chemical & pharmaceutical bulletin》2000,48(11):1778-1781
Triamino-substituted 1,3,5-triazine and pyrimidine derivatives were synthesized and tested for antitumor activities using some human cancer cell lines and murine leukemia cell lines. All the compounds having benzimidazolyl and morpholino groups as substituents on the 1,3,5-triazine ring showed antitumor activity. Pyrimidine derivatives having the same groups as substituents also showed antitumor activity. Among them, the compounds having 1-benzimidazolyl, morpholino and cis-2,3-dimethylmorpholino groups as substituents on the 1,3,5-triazine ring or pyrimidine ring exhibited the most potent antitumor activity, and these compounds exhibited no or very weak aromatase inhibitory activity. In contrast, the compounds having imidazolyl group instead of benzimidazolyl group as a substituent on the 1,3,5-triazine ring showed a potent aromatase inhibitory activity. 相似文献
72.
Hidehiro Gotô Ikuo Atsuya Tsutomu Shoji 《Fresenius' Journal of Analytical Chemistry》1968,234(5):333-339
Summary Examinations were made for the concurrent determination of magnesium and calcium in iron ores when present in about equal amounts, using the magnesium-calcium coupled type hollow-cathode lamp in atomic absorption spectroscopy, and a method of measurement was established. Concurrent determination was found to be easily possible by removal of the majority of iron by extraction with methyl isobutyl ketone and addition of strontium. Analytical precision was calculated and found to give satisfactory results (standard deviations: ±0.004% for Ca, ±0.006% for Mg).
Zusammenfassung Untersuchungen wurden angestellt über die Bestimmung von Magnesium und Calcium nebeneinander in ungefähr gleichen Mengen in Eisenerzen durch Atomabsorptionsspektrometrie. Verwendet wird die Ca-Mg-Doppel-Hohlkathodenlampe. Die Hauptmenge des Eisens wird durch Extraktion mit Methylisobutylketon zuvor entfernt. Außerdem ist zur Vermeidung einer Störung ein Zusatz von Strontium erforderlich. Es werden zufriedenstellende Ergebnisse erhalten (Standardabweichung: ±0,004% für Ca, ±0,006% für Mg).相似文献
73.
Summary An investigation has been carried out to establish a rapid method for the determination of vitamin B12 as cobalt in solid pharmaceutical samples by electrothermal atomization atomic absorption spectrometry with the solid sampling technique using an inner miniature cup. Calibration graphs of peak area versus mass of the element were constructed by use of a synthetic reference material (SyRM). The SyRM is prepared by coprecipitation of cobalt ions with magnesium(II) 8-quinolinate. In order to determine the accuracy of the proposed method, three pharmaceutical preparations were analyzed according to the proposed method using standardization against the SyRM and the results obtained compared with those when solutions of the same samples were analyzed by other techniques. There is good agreement between the results obtained from the proposed and the other method. The detection limit for cobalt in a solid pharmaceutical preparation is 0.15 ng/mg (i.e. 4 ng/mg of vitamin B12) for a typical sample mass of 1.0 mg.
Bestimmung von Vitamin B12 als Cobalt mit Hilfe der elektrothermischen Feststoff-AAS相似文献
74.
Jeong GH Hatakeyama R Hirata T Tohji K Motomiya K Yaguchi T Kawazoe Y 《Chemical communications (Cambridge, England)》2003,(1):152-153
Cesium encapsulation inside single-walled carbon nanotubes (SWNTs) is for the first time realized by ion irradiation of SWNTs immersed in a magnetized alkali-metal plasma, the configuration of which is confirmed to comprise three varieties by field emission type transmission electron microscopy (FE-TEM) and scanning TEM (STEM) observation. 相似文献
75.
Hara M Samori S Cai X Tojo S Arai T Momotake A Hayakawa J Uda M Kawai K Endo M Fujitsuka M Majima T 《The journal of physical chemistry. B》2005,109(2):973-976
Formation and decay processes of stilbene core radical cation (ST*+) during the photoinduced electron transfer have been studied for a series of stilbene bearing benzyl ether-type dendrons (D). ST*+ and the radical cation of peripheral dendron (D*+) were generated by intermolecular hole transfer from biphenyl radical cation, which was generated from photoinduced electron transfer from biphenyl to the singlet-excited 9,10-dicyanoanthracene in a mixture of acetonitrile and 1,2-dichloroethane (3:1). An intramolecular dimer radical cation of benzyl groups at the terminal of stilbene dendrimer was indicated as a hole trapping site. Subsequent hole transfer from the trapping site to the core ST generated ST*+. The shielding effects of D depending on the dendrimer generation on the growth and decay of ST*+ were observed. It was revealed for the first time that D acts as the hole trapping site and the hole conductor on the way of the exothermic hole transfer from the terminal of D to the central core ST. We also found that D inhibits the charge recombination with 9,10-dicyanoanthracene radical anion because of the steric hindrance. 相似文献
76.
Ohta K Kusumoto K Takao Y Towata A Kawakami S Murase Y Ohashi M 《Journal of chromatography. A》2002,956(1-2):147-158
The application of unmodified silica gel (Super Micro Bead Silica Gel B-5, SMBSG B-5) as a cation-exchange stationary phase in ion chromatography with indirect photometric detection (IC-IPD) for the separation of common mono- and divalent cations (Li+, Na+, NH4+, K+, Mg2+ and Ca2+) was carried out using various aromatic monoamines [tyramine [4-(2-aminoethyl)phenol], benzylamine, phenylethylamine, 2-methylpyridine and 2,6-dimethylpyridine] as eluents. When using these amines as eluents, the peak resolution between these mono- and divalent cations was not quite satisfactory and the peak shapes of NH4+ and K+ were largely destroyed on the SMBSG B-5 silica gel column. Hence, the application of SMBSG B-5 silica gel calcinated at 200, 400, 600, 800 and 1000 degrees C for 5 h in the IC-IPD was carried out. The peak shapes of the monovalent cations were greatly improved with increasing calcination temperature and, as a result, symmetrical peaks of these mono- and divalent cations were obtained on the SMBSG B-5 silica gel calcinated at 1000 degrees C as the stationary phase. In contrast, the peak resolution between these mono- and divalent cations was not improved. Therefore, crown ethers [18-crown-6 (1,4,7,10,13,15-hexaoxacyclooctadecane), 15-crown-5 (1,4,7,10,13-pentaoxacyclopentadecane)] were added to the eluent for the complete separation of these mono- and divalent cations. Excellent simultaneous separation and highly sensitive detection at 275 nm were achieved in 25 min on a column (150x4.6 mm I.D.) packed with SMBSG B-5 silica gel calcinated at 1000 degrees C by elution with 0.75 mM tyramine-0.25 mM oxalic acid at pH 5.0 containing either 1.0 mM 18-crown-6 or 10 mM 15-crown-5. 相似文献
77.
Satoru Onaka Masanobu Yaguchi Tomoji Ozeki Tetsuya Sunahara Michito Shiotsuka Makoto Horibe Akifumi Iida Katsuya Inoue Katsuya Sako 《Journal of organometallic chemistry》2005,690(1):57-68
The effect of the carbon chain-length for Ph2P-R-PPh2 (R = -CHCH-, -CH2-CH2-, -CH2-CH2-CH2-, and -CH2-CH2-CH2- CH2-) and S-(CH2)n-pyridine ligand (n = 0 to 2) on the aurophilic interaction has been explored systematically. The effect of the N position in x-mercaptopyridine (x = 2 or 4) toward Au(I) center and/or the SR group was also investigated. X-ray structural study was made for 12 new derivatives. The Au-Au distances are below 3.0 Å for 2-S-pyridine derivatives with Ph2P-CHCH-PPh2 (t-dpen) and Ph2P-CH2-CH2-PPh2 (dppe) ligand and the pyridine N atoms come in close contact with the H atoms of these diphosphine carbon chains. A local coplanar conformation is formed between 2-S-pyridine and Au-P-CH groups for these derivatives. The carbon chain lengths are not too consequential on the induction of aurophilicity. Various infinite and/or dimer structures have been revealed from single crystal X-ray analysis for the present series of compounds. 相似文献
78.
Cover Picture: Improvement in Aqueous Solubility of Retinoic Acid Receptor (RAR) Agonists by Bending the Molecular Structure (Chem. Asian J. 15/2016)
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79.
Shunsuke Yanagi Akihisa Matsumoto Dr. Naoyuki Toriumi Yusuke Tanaka Dr. Kazunori Miyamoto Dr. Atsuya Muranaka Prof. Dr. Masanobu Uchiyama 《Angewandte Chemie (International ed. in English)》2023,62(11):e202218358
Activatable near-infrared (NIR) dyes responsive to external stimuli are used in medical and other applications. Here, we describe the design and synthesis of bench-stable 18π- and 20π-electron benzitetraazaporphyrins (BzTAPs) possessing redox-switchable NIR properties. X-Ray, NMR, and UV/Visible-NIR analyses revealed that 20π-electron BzTAP 1 exhibits NIR absorption and antiaromaticity with a paratropic ring-current, while 18π-electron BzTAP 2 shows weakly aromatic character with NIR inertness. Notably, the NIR-silent BzTAP 2 was readily converted to the NIR-active BzTAP 1 in the presence of mild reducing agents such as amine. The intense NIR absorption band of BzTAP 1 is in sharp contrast to the very weak absorption bands of previously reported antiaromatic porphyrinoids. Molecular orbital analysis revealed that symmetry-lowering perturbation of the 20π-electron porphyrinoid skeleton enables the HOMO–LUMO transition of 1 to be electric-dipole-allowed. BzTAPs are expected to be useful for constructing activatable NIR probes working in reductive environments. 相似文献
80.
Azuma Matsuura Hiroyuki Sato Wataru Sotoyama Atsuya Takahashi Minoru Sakurai 《Journal of Molecular Structure》2008,860(1-3):119-127
The absorption maxima, λmax, of various organic dyes such as indigo, azobenzene, phenylamine, hydrazone, anthraquinone, naphthoquinone, and malachite green were calculated using the AM1, PM3, and PM5 semiempirical molecular orbital theories with the configuration interaction singles (CIS) and random phase approximation (RPA) approaches. The calculated λmax were then compared with the values obtained by CNDO/S, INDO/S, ab initio CIS, and time-dependent density functional theory (TD-DFT). We found that the λmax values calculated by AM1, PM3, and PM5 were in good correlation with the observed λmax values. When B3LYP/cc-pVDZ optimized geometries were used, the square of the correlation coefficients between the calculated and observed λmax, , at the AM1-RPA, PM3-RPA, and PM5-RPA levels were 0.891, 0.897, and 0.927, respectively. In particular, at PM5-RPA//B3LYP/cc-pVDZ was the largest among those obtained from all the other calculations including TD/B3LYP/cc-pVDZ//B3LYP/cc-pVDZ . Accordingly, the standard deviation of the difference between observed and calculated λmax by the linear regression function at PM5-RPA//B3LYP/cc-pVDZ was the smallest. It was therefore concluded that this method was the most promising for the prediction of λmax of various dyes among the computational methods studied here. When AM1 optimized geometries were used, at the AM1-RPA, PM3-RPA, and PM5-RPA levels were 0.822, 0.841, and 0.901, respectively, and they were also comparable to that at TD/B3LYP/cc-pVDZ//B3LYP/cc-pVDZ. Therefore, although some calibration efforts may be needed for AM1 geometries, PM5-RPA(CIS)//AM1 may be a second candidate available for the prediction of the absorption maxima of dyes, especially in the case of emphasizing computational cost. 相似文献