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排序方式: 共有159条查询结果,搜索用时 187 毫秒
71.
Ulviye Acar Çevik Derya Osmaniye Begüm N. Sağlik Serkan Levent Betül K. Çavuşoğlu Abdullah B. Karaduman Ümide D. Özkay Yusuf Özkay Zafer A. Kaplancikli Gülhan Turan 《Journal of heterocyclic chemistry》2020,57(5):2225-2233
Monoamine oxidases (MAO) are enzymes that catalyze the oxidative deamination of monoamines such as dopamine, noradrenaline, adrenaline, and serotonin. Recent studies have shown that numerous benzothiazole derivatives exhibit hMAO inhibitory activity in the micromolar concentration range. In this study, a novel series of benzothiazole-thiadiazole (5a-5l ) was synthesized and characterized their chemical structures by 1H-NMR, 13C-NMR, and Mass spectroscopy. These compounds were evaluated as inhibitors for types A and B MAO enzymes. Compounds 5f and 5l were the most active derivatives in the series with an IC50 values of 0.107 ± 0.003 and 0.128 ± 0.004, respectively. Furthermore, cytotoxicity of compounds 5f and 5l were investigated and found as non-cytotoxic. 相似文献
72.
Turan Ozturk David C. Povey John D. Wallis 《Phosphorus, sulfur, and silicon and the related elements》2013,188(1):313-324
Abstract The effective size of bonded divalent sulfur in S…S contacts is a function of the orientation of the groups, with the shortest contacts occurring when the groups are coplanar. A lower limit for the loner is indicated by the structures of the 2-(1,3-benzodithiol-2-ylidenemethyl)-1,3-benzodithiolium and 2-(1,3-dithiolan-2-ylidenemethyl)-1,3-dithiolanium cations, 2 and 3. These show almost mm symmetry with all four sulfur atoms involved in stabilisation of the positive charge. Short intramolecular sulfur… sulfur contact distances, 0.5–0.7 Å within the sum of traditional van der Waals radii, and maximised by in-plane angular distortions, indicate a lower limit to the effective size of the bonded divalent sulfur atom of ca. 1.45 Å. 相似文献
73.
Tayfun Yilmaz Perihan Unak Fazilet Zumrut Biber Muftuler Emin Ilker Medine Serhan Sakarya Cigdem Acar Ichedef Turan Unak 《Journal of Radioanalytical and Nuclear Chemistry》2013,295(2):1395-1404
Diethylstilbestrol (DES) is a synthetic non-steroidal estrogen, pharmacologic effects of which resemble natural estrons; today it is being used to treat some types of postmenopausal breast cancer and advanced prostate cancer. The aim of current study is conjugation of glucuronic acid (G) to DES and to evaluate radiopharmaceutical potential of this estrogen glucuronide derivative (DESG) which is specific to β glucuronidase enzyme consisting tumor cells. Taking into consideration the compatibility to the chemical structures of the synthesized product, 131I and 125I were chosen as the appropriate radionuclides and DESG was labeled with these radionuclides utilizing iodogen method. The radiochemical yields of 125/131I-DESG were over 90 % according to thin layer radio chromatography method. The biodistribution of 131I-DESG in healthy female Wistar Albino rats has been investigated and the range of the breast/blood and breast/muscle ratios were approximately 2 and 13 in 240 min for ER unsaturated studies. Effects of the radioiodinated DES and DESG on the cells were examined using MCF-7, A-549, Caco-2 cell lines. 125I-DESG has higher incorporation percentages than 125I-DES on MCF-7 cells. The radioiodinated DESG has the desired radiopharmaceutical properties which could be candidate radiopharmaceuticals for diagnosis and especially radionuclide therapy of breast tumors. 相似文献
74.
75.
Let g be a non-zero rapidly decreasing function and w be a weight function. In this article in analog to modulation space, we define the space M(p, q, w)(Rd) to be the subspace of tempered distributions f ∈ S′(Rd) such that the Gabor transform Vg(f) of f is in the weighted Lorentz space L(p, q, wdμ) (R2d). We endow this space with a suitable norm and show that it becomes a Banach space and invariant under time frequence shifts for 1 ≤ p, q ≤∞. We also investigate the embeddings between these spaces and the dual space of M(p, q, w)(Rd). Later we define the space S(p, q, r, w, ω)(Rd) for 1 < p < ∞, 1 ≤ q ≤∞. We endow it with a sum norm and show that it becomes a Banach convolution algebra. We also discuss some properties of S(p, q, r, w, ω)(Rd). At the end of this article, we characterize the multipliers of the spaces M(p, q, w)(Rd) and S(p, q, r, w, ω)(Rd). 相似文献
76.
Eylem Turan Tuncer Caykara 《Journal of polymer science. Part A, Polymer chemistry》2011,49(13):2818-2822
In this study, single electron transfer‐living radical polymerization (SET–LRP) of N‐isopropylacrylamide (NIPAM) in the presence of 2‐mercaptoethylamine chain transfer agent (CTA) was carried out by Cu(0) generated in situ from the disproportionation of CuBr/2,2′‐bipyridine (2,2′‐bpy) in N,N‐dimethylformamide (DMF) at 90 °C. Analysis of polymerization kinetics in the presence of CTA showed that the premature termination of growing polymer chains leads to retardation. The apparent rate constant of polymerization (k) decreased from 4.49 × 10?4 to 2.59 × 10?4 min?1 with increasing CTA concentration. The initiator efficiency (Ieff) and the chain transfer constant (Cs) were found to be 0.524 and 0.286, respectively. The molecular weights of poly(N‐isopropylacrylamide) [poly(NIPAM)] produced were significantly higher than the predicted values, and the polydispersities were less than 1.22. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011 相似文献
77.
This paper is concerned with the dynamic system nonlinear behaviour encountered in classical thermo-acoustic instability. The Poincaré map is adopted to analyse the stability of a simple non-autonomous system considering a harmonic oscillation behaviour for the combustion environment. The bifurcation diagram of a one-mode model is obtained where the analysis reveals a variety of chaotic behaviours for some select ranges of the bifurcation parameter. The bifurcation parameter and the corresponding period of a two-mode dynamic model are calculated using both analytical and numerical methods. The results computed by different methods are in good agreement. In addition, the dependence of the bifurcation parameter and the period on all the relevant coefficients in the model is investigated in depth. 相似文献
78.
79.
Aysun Ipek Paksoy Cansu Yassi Akdag Burcu Selen Caglayan Ahmet Erhan Aksoylu 《国际化学动力学杂志》2019,51(2):138-145
Carbon dioxide reforming of methane (CDRM) is an effective route to utilize CO2 and CH4, the most abundant, thermodynamically stable and hazardous greenhouse gases. To overcome the economical impediments to favor CDRM's industrial applicability, its mechanistic features need to be revealed both for developing efficient catalysts and optimizing operational conditions. In this context, this work aims to obtain power-law type CDRM kinetic expressions over 5%Co–2%Ce/ZrO2 and 10%Co–2%Ce/ZrO2 catalysts and compare and analyze mechanistic routes to elucidate the effect of the Co:Ce ratio on kinetics. The empirical power-law type rate expressions were estimated with the reaction orders of 1.63 and 1.12 for CH4 and 0.29 and –0.12 for CO2 for 5%Co–2%Ce/ZrO2 and 10%Co–2%Ce/ZrO2 catalysts, respectively. Limited CH4 activation and, thus, carbon formation due to low Co loading lead to accumulation of surface oxygen on ZrO2 as redox ability of Ce becomes suppressed. This causes higher CO2 activation barrier. The presence of H2 in the feed slows down mechanistic steps involving CHx. The reactions including CH4 activation, most probably reversible direct CH4 dissociation, are found to be rate determining. 相似文献
80.