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411.
Poulsen A William A Blanchard S Lee A Nagaraj H Wang H Teo E Tan E Goh KC Dymock B 《Journal of computer-aided molecular design》2012,26(4):437-450
Macrocycles from our Aurora project were screened in a kinase panel and were found to be active on other kinase targets, mainly
JAKs, FLT3 and CDKs. Subsequently these compounds became leads in our JAK2 project. Macrocycles with a basic nitrogen in the
linker form a salt bridge with Asp86 in CDK2 and Asp698 in FLT3. This residue is conserved in most CDKs resulting in potent
pan CDK inhibition. One of the main project objectives was to achieve JAK2 potency with 100-fold selectivity against CDKs.
Macrocycles with an ether linker have potent JAK2 activity with the ether oxygen forming a hydrogen bond to Ser936. A hydrogen
bond to the equivalent residues of JAK3 and most CDKs cannot be formed resulting in good selectivity for JAK2 over JAK3 and
CDKs. Further optimization of the macrocyclic linker and side chain increased JAK2 and FLT3 activity as well as improving
DMPK properties. The selective JAK2/FLT3 inhibitor 11 (Pacritinib, SB1518) has successfully finished phase 2 clinical trials for myelofibrosis and lymphoma. Another selective
JAK2/FLT3 inhibitor, 33 (SB1578), has entered phase 1 clinical development for the non-oncology indication rheumatoid arthritis. 相似文献
412.
Chang Xu Yongxin Li Lai Yoong Goh Sumod A. Pullarkat 《Journal of organometallic chemistry》2012,696(26):4207-4214
The reaction of [Cp1IrCl2]2 (Cp* = η5 ? C5Me5) with the tridentate 3-thiapentane-1,5-dithiolate ligand, S(CH2CH2S?)2 (tpdt), led to the formation of [Cp1Ir(η3 ? tpdt)] (1) in 81% isolated yield. Subsequent reactions of 1 with [Cp1IrCl2]2 in 2:1 and 1:1 molar equiv ratios resulted in the formation of [Cp1Ir(μ ? η2:η3 ? tpdt)Cp1IrCl][PF6] (2) and [Cp1Irμ ? η2:η3 ? tpdt)Cp1IrCl][Cp1IrCl3] (3) in 86 and 79% yields, respectively, based on 1, whereas the reactions of 1 with [(COD)IrCl]2 (COD = 1,5-cyclooctadiene) in 2:1 and 1:1 molar equiv ratios resulted in the formation of the homo-bimetallic derivatives Cp1Ir(μ ? η1:η3 ? tpdt)(COD)IrCl (4) (92% yield) and [Cp1Ir(μ ? η2:η3 ? tpdt)(COD)Ir] [(COD)IrCl2] (5) (82% yield). Reactions between 1 and [(COD)RhCl]2, yielded the hetero-bimetallic derivatives Cp1Ir(μ ? η1:η3 ? tpdt)(COD)RhCl (6) and [Cp1Ir(μ ? η2:η3 ? tpdt)(COD)Rh][(COD)RhCl2] (7), in 92 and 93% yields, respectively. The reaction of 1 with methyl iodide gave mono-methylated derivative [Cp1Ir(η3-C4H8S3Me)]I (8) (93% yield). All these compounds have been comprehensively characterized. 相似文献
413.
Joel Weiqiang Goh Kian Guan Lim Melvyn Sim Weina Zhang 《European Journal of Operational Research》2012
We propose a new approach to portfolio optimization by separating asset return distributions into positive and negative half-spaces. The approach minimizes a newly-defined Partitioned Value-at-Risk (PVaR) risk measure by using half-space statistical information. Using simulated data, the PVaR approach always generates better risk-return tradeoffs in the optimal portfolios when compared to traditional Markowitz mean–variance approach. When using real financial data, our approach also outperforms the Markowitz approach in the risk-return tradeoff. Given that the PVaR measure is also a robust risk measure, our new approach can be very useful for optimal portfolio allocations when asset return distributions are asymmetrical. 相似文献
414.
Say Song Goh Zhi Yuan Lim Zuowei Shen 《Applied and Computational Harmonic Analysis》2006,20(3):411-421
For a given set of wavelets Ψ, we provide a general, and yet simple, method to derive a new set of wavelets such that each wavelet in is either symmetric or antisymmetric. The affine system generated by is a tight frame for the space whenever the affine system generated by Ψ is so. Further, when Ψ is constructed via a multiresolution analysis, can also be derived from a, but possibly different, multiresolution analysis. If moreover the multiresolution analysis for constructing Ψ is generated by a symmetric refinable function, then is obtained from the same multiresolution analysis. 相似文献
415.
416.
Su Kong Chong Boon Tong Goh Yuen-Yee Wong Hong-Quan Nguyen Hien Do Ishaq Ahmad Zarina Aspanut Muhamad Rasat Muhamad Chang Fu Dee Saadah Abdul Rahman 《Journal of luminescence》2012,132(6):1345-1352
High density of silicon nanowires (SiNWs) were synthesized by a hot-wire assisted plasma enhanced chemical vapor deposition technique. The structural and optical properties of the as-grown SiNWs prepared at different rf power of 40 and 80 W were analyzed in this study. The SiNWs prepared at rf power of 40 W exhibited highly crystalline structure with a high crystal volume fraction, XC of ~82% and are surrounded by a thin layer of SiOx. The NWs show high absorption in the high energy region (E>1.8 eV) and strong photoluminescence at 1.73 to 2.05 eV (red–orange region) with a weak shoulder at 1.65 to 1.73 eV (near IR region). An increase in rf power to 80 W reduced the XC to ~65% and led to the formation of nanocrystalline Si structures with a crystallite size of <4 nm within the SiNWs. These NWs are covered by a mixture of uncatalyzed amorphous Si layer. The SiNWs prepared at 80 W exhibited a high optical absorption ability above 99% in the broadband range between 220 and ~1500 nm and red emission between 1.65 and 1.95 eV. The interesting light absorption and photoluminescence properties from both SiNWs are discussed in the text. 相似文献
417.
Goh L Chen K Bhamidi V He G Kee NC Kenis PJ Zukoski CF Braatz RD 《Crystal growth & design》2010,10(6):2515-2521
The measured induction times in droplet-based microfluidic systems are stochastic and are not described by the deterministic population balances or moment equations commonly used to model the crystallization of amino acids, proteins, and active pharmaceutical ingredients. A stochastic model in the form of a Master equation is formulated for crystal nucleation in droplet-based microfluidic systems for any form of nucleation rate expression under conditions of time-varying supersaturation. An analytical solution is provided to describe the (1) time evolution of the probability of crystal nucleation, (2) the average number of crystals that will form at time t for a large number of droplets, (3) the induction time distribution, and (4) the mean, most likely, and median induction times. These expressions are used to develop methods for determining the nucleation kinetics. Nucleation kinetics are determined from induction times measured for paracetamol and lysozyme at high supersaturation in an evaporation-based high-throughput crystallization platform, which give low prediction errors when the nucleation kinetics were used to predict induction times for other experimental conditions. The proposed stochastic model is relevant to homogeneous and heterogeneous crystal nucleation in a wide range of droplet-based and microfluidic crystallization platforms. 相似文献
418.
The separation distance (d12) between a diffusing particle and its host necessary for a successful diffusion was estimated for diffusion-controlled crystal growth of BaWO4 from Na2WO4 melts. Such distances slightly increased with increased cooling rates (RT) and crystallization temperatures (T0). The energy (E), enthalpy (ΔHa), entropy (ΔSa) and free-energy (ΔGa) of activation, and the probability factor (P) were also estimated. These parameters did not change with the changes in RT and T0. 相似文献
419.
Amino acids such as phenylalanine (Phe) are key building blocks of proteins and other biomolecules. Although recent advancements in electrochemical sensors have enabled the rapid detection of Phe, these sensors are often destructive as they irreversibly oxidise Phe. In addition, most of them rely on biorecognition elements, which suffer from limited stability at ambient conditions and sensitivity towards environmental fluctuations. Herein, we report the first example of ion transfer voltammetry of Phe using an all-solid-state ion-selective electrode (ISE). The reversibility of this technique enables both the sensor and the Phe sample to be reused. The optimal voltammetric ISE (VISE) exhibits near Nernstian response (56.8 mV/decade) towards Phe and selectivity against amino acids of all classes (hydrophobic, hydrophilic and charged). Voltammetric interrogation of the ISE significantly enhances sensitivity, linear range, selectivity, and stability as compared to traditional open circuit potential measurements. Phe levels in a commercial nutritional supplement and drinking waters were determined to demonstrate the viability of our sensor in real life applications. This proof-of-concept can be applied to develop VISEs for other amino acids and biological ions for healthcare and nutrition sensing. 相似文献