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排序方式: 共有174条查询结果,搜索用时 15 毫秒
91.
Jianqiang Cheng Richard Li-Yang Chen Habib N. Najm Ali Pinar Cosmin Safta Jean-Paul Watson 《Computational Optimization and Applications》2018,70(2):479-502
Increasing penetration levels of renewables have transformed how power systems are operated. High levels of uncertainty in production make it increasingly difficulty to guarantee operational feasibility; instead, constraints may only be satisfied with high probability. We present a chance-constrained economic dispatch model that efficiently integrates energy storage and high renewable penetration to satisfy renewable portfolio requirements. Specifically, we require that wind energy contribute at least a prespecified proportion of the total demand and that the scheduled wind energy is deliverable with high probability. We develop an approximate partial sample average approximation (PSAA) framework to enable efficient solution of large-scale chance-constrained economic dispatch problems. Computational experiments on the IEEE-24 bus system show that the proposed PSAA approach is more accurate, closer to the prescribed satisfaction tolerance, and approximately 100 times faster than standard sample average approximation. Finally, the improved efficiency of our PSAA approach enables solution of a larger WECC-240 test system in minutes. 相似文献
92.
In this work, we focus on obtaining the exact solutions of the fifth-order semi-linear and non-linear dispersive partial differential equations, which have the second-order diffusion-like (porous-type) non-linearity. The proposed equations were not studied in the literature in the sense of the exact solutions. We reveal solutions of the proposed equations using the classical Riccati equations method. The obtained exact solutions, which can play a key role to simulate non-linear waves in the medium with dispersion and diffusion, are illustrated and discussed in details. 相似文献
93.
This study attempts to give an insight into the trend in the performance of the Turkish banking sector by conducting a panel data fixed effects regression analysis. The results reveal that efficiency change is negatively related to the number of branches. We find a positive relationship between the loan ratio and the performance indices efficiency and efficiency change. Furthermore, bank capitalization is positively related to efficiency change. Interestingly however, return on equity is not statistically significant in explaining any of the efficiency measures. There is also no robust relationship between foreign ownership and efficiency. Finally, restructuring attempts in post-crises epoch robustly account for the improvement in efficiency scores in recent years. 相似文献
94.
Muammer Ozgoren Engin Pinar Besir Sahin Huseyin Akilli 《International Journal of Heat and Fluid Flow》2011,32(6):1138-1146
An experimental investigation of flow structures downstream of a circular cylinder and sphere immersed in a free-stream flow is performed for Re = 5000 and 10,000 using qualitative and quantitative flow visualization techniques. The obtained results are presented in terms of time-averaged velocity vectors, patterns of streamlines, vorticity, Reynolds stress correlations and turbulent kinetic energy distributions. Flow data reveal that the size of wake flow region, the location of singular and double points, the peak values of turbulence quantities, such as Reynolds stress correlations, vorticity fluctuations and turbulent kinetic energy vary as a function of models’ geometry and Reynolds Numbers. The concentration of small scale vortices is more dominant in the wake of the sphere than that of the cylinder. The maximum value of turbulent kinetic energy (TKE) occurs close to the saddle point for the cylinder case while two maximum values of TKE occur along shear layers for the sphere one because of the 3-D flow behavior. 相似文献
95.
In this paper, we address the preventive health aspects of genetic problems in the Middle East and provide guidelines to prioritize preventive strategies. Applications of various novel genetic techniques such as comprehensive neonatal screening, high throughput heterozygote detection, preimplantation genetic diagnosis, Affymetrix systems, the NanoChip system and a new way of sensitive karyotyping for single-cell chromosome abnormalities are discussed. In conclusion, from the various genetic techniques available, each country should adopt strategies most suitable to its genetic needs and should prioritize the programs to be used in prevention. 相似文献
96.
Wynne KJ Makal U Kurt P Gamble L 《Langmuir : the ACS journal of surfaces and colloids》2007,23(21):10573-10580
Polyurethanes containing poly(2-trifluoroethoxymethyl-2-methyl)-co-(2-bromomethyl-2-methyl)-1,3-propylene oxide (co-polyoxetane) soft blocks, P[3FOx:BrOx-m:n], were prepared and used (0.5-2 wt %) to modify the surface properties of a conventional polyurethane. The substrate polyurethane was composed of an isophorone diisocyanate/butanediol hard block and a polytetramethylene oxide soft block [IPDI/BD(50%)-PTMO(2000)]. A combination of tapping mode atomic force microscopy (TM-AFM), X-ray photoelectron spectroscopy (XPS), and dynamic contact angle (DCA) studies showed that the fluorous polyurethane surface modifiers confer surface properties similar to those of the parent at 0.5-1.0 wt %. The retention of initial wetting behavior in water was enhanced with higher ratios of 3FOx:BrOx that corresponds to increasing fluorous character. A semifluorinated chaperone is necessary to surface concentrate -CH2Br groups. Negligible Br was detected by XPS when the P[BrOx]-soft block polyurethane was used as a surface modifier (0.5%) and the wetting behavior was similar to that of the bulk polyurethane. Despite being hydrophobic (theta adv = 102 degrees) the P[BrOx]-soft block polyurethane is not a polymer surface modifier under the conditions described herein. The calculated solubility parameters for PTMO and P[BrOx], which are similar, support the notion of BrOx miscibility with the base polyurethane. The combination of miscibility of BrOx repeat units and lack of an end-group-like architecture minimizes BrOx surface concentration in the chosen bulk polyurethane. 相似文献
97.
Chiara Da Pieve Marta Costa Braga David R. Turton Frank A. Valla Pinar Cakmak Karl-Heinz Plate Gabriela Kramer-Marek 《Molecules (Basel, Switzerland)》2022,27(3)
A large number of applications for fibroblast activation protein inhibitors (FAPI)-based PET agents have been evaluated in conditions ranging from cancer to non-malignant diseases such as myocardial infarction. In particular, 68Ga-FAPI-46 was reported to have a high specificity and affinity for FAP-expressing cells, a fast and high accumulation in tumor lesions/injuries together with a fast body clearance when investigated in vivo. Due to the increasing interest in the use of the agent both preclinically and clinically, we developed an automated synthesis for the production of 68Ga-FAPI-46 on a Trasis AiO platform. The new synthetic procedure, which included the processing of the generator eluate using a strong cation exchange resin and a final purification step through an HLB followed by a QMA cartridge, yielded 68Ga-FAPI-46 with high radiochemical purity (>98%) and apparent molar activity (271.1 ± 105.6 MBq/nmol). Additionally, the in vitro and in vivo properties of the product were assessed on glioblastoma cells and mouse model. Although developed for the preparation of 68Ga-FAPI-46 for preclinical use, our method can be adapted for clinical production as a reliable alternative to the manual (i.e., cold kit) or modular systems preparations already described in the literature. 相似文献
98.
Pinar Sinem Omurtag Ufuk Saim Gunay Aydan Dag Hakan Durmaz Gurkan Hizal Umit Tunca 《Journal of polymer science. Part A, Polymer chemistry》2013,51(10):2252-2259
The Diels‐Alder reaction as a click reaction strategy is applied to the preparation of well‐defined polycarbonate (PC)‐block copolymers. A well‐defined α‐anthracene‐terminated polycarbonate (PC‐anthracene) is prepared using 9‐anthracene methanol as an initiator in the ring opening polymerization of benzyl 5‐methyl‐2‐oxo‐1,3‐dioxane‐5‐carboxylate in CH2Cl2 at room temperature for 5 h. Next, a well‐defined α‐furan protected maleimide‐terminated‐poly(ethylene glycol) (PEG11‐MI or PEG37‐MI), ‐poly(methyl methacrylate) (PMMA26‐MI), and ‐poly(ε‐caprolactone) (PCL27‐MI) were clicked with the PC‐anthracene at reflux temperature of toluene to yield their corresponding PC‐based block copolymers (PC‐b‐PEG, PC‐b‐PMMA, and PC‐b‐PCL). The homopolymer precursors and their block copolymers were characterized by using the GPC, NMR and UV analysis. © 2013 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013 相似文献
99.
From the dichloromethane extract of Nepeta sorgerae, the isolation and structure elucidation are now reported of a new isopimarane diterpenoid, named sorgerolone, and two known triterpenoids, oleanolic acid and ursolic acid. Antioxidant activity of the extracts and the isolated terpenoids was determined by the DPPH free radical scavenging and lipid peroxidation inhibition (beta-carotene bleaching) methods. Anticholinesterase activity of the extracts and isolates was investigated by Ellman's method against AChE and BChE enzymes. Although the antioxidant activity results were low, the AChE enzyme inhibition of the extracts and terpenoids was very promising. 相似文献
100.
DNA biosensors based on nucleic acid hybridization processes are rapidly being developed towards the goal of rapid and inexpensive diagnosis of genetic and infectious diseases. Electrochemical transducers are often being used for detecting the DNA hybridization event, due to their high sensitivity, small dimensions, low cost, and compatibility with microfabrication technology. In this study, an electrochemical biosensor for the voltammetric detection of DNA sequences related to the Hepatitis B virus (HBV) and TT virus (TTV) from polymerase chain reaction (PCR) amplified real samples is described for the first time. The biosensor relies on the immobilization of the 21- or 24-mer single stranded oligonucleotides (probe) related to the HBV and TTV sequences and hybridization of these oligonucleotides with their complementary sequences (target) at carbon paste electrode (CPE). The extent of hybridization between the probe and target sequences was determined by using square wave voltammetry (SWV) with moving average baseline correction and methylene blue (MB) as the hybridization indicator. As a result of the interaction between MB and the bound guanine bases of hybrid at CPE surface, the MB signal decreased, when it was compared with the MB signal, which was observed with probe modified CPE. The difference between the MB signals, obtained from the hybrid modified and the probe modified CPE is used to detect the DNA sequences of the infectious diseases from PCR amplified real samples. Numerous factors affecting the target hybridization and indicator binding reactions are optimized to maximize the sensitivity. 相似文献