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101.
102.
Hossein Eshghi Ali Javid Amir Khojastehnezhad Farid Moeinpour Fatemeh F. Bamoharram Mehdi Bakavoli Masoud Mirzaei 《催化学报》2015,(3)
A novel magnetic acidic catalyst comprising Preyssler (H14[NaP5W30O110]) heteropoly acid support‐ed on silica coated nickel ferrite nanoparticles (NiFe2O4@SiO2) was prepared. The catalyst was character... 相似文献
103.
This paper describes two optimal subgradient algorithms for solving structured large-scale convex constrained optimization. More specifically, the first algorithm is optimal for smooth problems with Lipschitz continuous gradients and for Lipschitz continuous nonsmooth problems, and the second algorithm is optimal for Lipschitz continuous nonsmooth problems. In addition, we consider two classes of problems: (i) a convex objective with a simple closed convex domain, where the orthogonal projection onto this feasible domain is efficiently available; and (ii) a convex objective with a simple convex functional constraint. If we equip our algorithms with an appropriate prox-function, then the associated subproblem can be solved either in a closed form or by a simple iterative scheme, which is especially important for large-scale problems. We report numerical results for some applications to show the efficiency of the proposed schemes. 相似文献
104.
Cargo Pendulation Reduction of Ship-Mounted Cranes 总被引:4,自引:0,他引:4
Ship-mounted cranes are used to transfer cargo from large container ships to smaller lighters when deep-water ports are not
available. The wave-induced motion of the crane ship can produce large pendulations of the cargo being hoisted and cause operations
to be suspended. In this work, we show that it is possible to reduce these pendulations significantly by controlling the slew
and luff angles of the boom. Such a control can be achieved with the heavy equipment that is already part of the crane so
that retrofitting existing cranes would require a small effort. Moreover, the control is superimposed on the commands of the
operator transparently. The successful control strategy is based on delayed feedback of the angles of the cargo-hoisting cable
in and out of the plane of the boom and crane tower. Its effectiveness is demonstrated in a fully nonlinear three-dimensional
computer simulation and in an experiment with a 1/24th-scale model of a T-ACS (The Auxiliary Crane Ship) crane mounted on
a platform moving with three degrees of freedom. The results demonstrate that the pendulations can be significantly reduced,
and therefore the range of sea conditions in which cargo-transfer operations can take place can be greatly expanded. 相似文献
105.
Competition of methyltrioxorhenium (MTO) with osmium tetroxide (OsO4) toward L = pyridine and its derivatives, based on the equilibrium constant for the reaction OsO4·L + MTO = MTO·L + OsO4, has been measured. A successful correlation of log Keq with the Hammett σ constants of the substituents on the ligands was realized. A negative reaction constant, obtained for the reactions, shows that a more positive charge expands on the pyridine nitrogen in the complex MTO·L as compared with the complex OsO4·L. So, the rhenium center acts as a better electron acceptor than osmium center. The thermodynamic parameters have been obtained and an excellent linear relationship was observed between the enthalpy and entropy of the reactions. 相似文献
106.
Isothermal differential scanning calorimetry (DSC) was used to study the curing behavior of epoxy prepreg Hexply®1454 system, based on diglycidyl ether of bisphenol A (DEGBA)/dicyandiamid (DICY) reinforced by glass fiber. Cure kinetics of an autocatalytic‐type reaction were analyzed by general form of conversion‐dependent function. The characteristic feature of conversion‐dependent function was determined using a reduced‐plot method where the temperature‐dependent reaction rate constant was analytically separated from the isothermal data. An autocatalytic kinetic model was used; it can predict the overall kinetic behavior in the whole studied cure temperature range (115–130°C). The activation energy and pre‐exponential factor were determined as: E = 94.8 kJ/mol and A = 1.75 × 1010 sec?1 and reaction order as 2.11 (m + n = 0.65 + 1.46 = 2.11). A kinetic model based on these values was developed by which the prediction is in good agreement with experimental values. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
107.
Automatic control of mesh movement is mandatory in many fluid flow and fluid-solid interaction problems. This paper presents a new strategy, called reduced domain strategy (RDS), which enhances the efficiency of node connectivity-based mesh movement methods and moves the unstructured grid locally and effectively. The strategy dramatically reduces the grid computations by dividing the unstructured grid into two active and inactive zones. After any local boundary movement, the grid movement is performed only within the active zone. To enhance the efficiency of our strategy, we also develop an automatic mesh partitioning scheme. This scheme benefits from a new quasi-structured mesh data ordering, which determines the boundary of active zone in the original unstructured grid very easily. Indeed, the new partitioning scheme eliminates the need for sequential reordering of the original unstructured grid data in different mesh movement applications. We choose the spring analogy method and apply our new strategy to perform local mesh movements in two boundary movement problems including a multi-element airfoil with moving slat or deforming main body section. We show that the RDS is robust and cost effective. It can be readily employed in different node connectivity-based mesh movement methods. Indeed, the RDS provides a flexible local grid deformation tool for moving grid applications. 相似文献
108.
Mahdokht Kalantari Masoud Rabbani Mahmood Ebadian 《Applied Mathematical Modelling》2011,35(3):1363-1377
In this paper, we present a novel decision support system for order acceptance/rejection in a hybrid Make-to-Stock/Make-to-Order production environment. The proposed decision support system is comprised of five steps. At the first step, the customers are prioritized based on a fuzzy TOPSIS method. Rough-cut capacity and rough-cut inventory are calculated in the second step and in case of unavailability in capacity and materials, some undesirable orders are rejected. Also, proper decisions are made about non-rejected orders. At the next step, prices and delivery dates of the non-rejected orders are determined by running a mixed-integer mathematical programming model. At the fourth step, a set of guidelines are proposed to help the organization negotiate over price and due date with the customers. In the next step, if the customer accepts the offered price and delivery date, the order is accepted and later considered in the production schedule of the shop floor, otherwise the order is rejected. Finally, numerical experiments are conducted to show the tractability of the applied mathematical programming model. 相似文献
109.
Mehdi Dehghan Masoud Hajarian 《Journal of Computational and Applied Mathematics》2011,235(15):4325-4336
Many problems in the areas of scientific computing and engineering applications can lead to the solution of the linear complementarity problem LCP (M,q). It is well known that the matrix multisplitting methods have been found very useful for solving LCP (M,q). In this article, by applying the generalized accelerated overrelaxation (GAOR) and the symmetric successive overrelaxation (SSOR) techniques, we introduce two class of synchronous matrix multisplitting methods to solve LCP (M,q). Convergence results for these two methods are presented when M is an H-matrix (and also an M-matrix). Also the monotone convergence of the new methods is established. Finally, the numerical results show that the introduced methods are effective for solving the large and sparse linear complementary problems. 相似文献
110.
Hanif MA Al-Maskri AY Al-Mahruqi ZM Al-sabahi JN Al-Azkawi A Al-Maskari MY 《Natural product communications》2011,6(10):1451-1454
Three wild Omani plants, Moringa peregrina, Acacia nilotica and Rhazya stricta, were selected for the present study. Na, K and Ca contents were determined using flame photometric analysis. M. peregrina seeds (22.5 mg/g) and pods (27.7 mg/g) had higher Na contents than A. nilotica (0.33 mg/g) and R. stricta (0.30 mg/g), whereas the K and Ca contents of R. stricta were significantly higher than those of the other two plants. The protein content was lowest in R. stricta (9.8%) and highest in M peregrina seeds (21.0%). The highest total phenolic contents (TPC) were found in M. peregrina seeds (350.3 mg/g) and the lowest in A. nilotica (66.1 mg/g). The major component of M. peregrina seed oil was oleic acid (74.7%). Gas chromatographic-mass spectrometric analysis (GC-MS) revealed that octadecanal (30.9%) was the major compound in A. nilotica. The presence of various phenolics and flavonoids in M. peregrina, A. nilotica and R. stricta were confirmed by high performance liquid chromatography (HPLC). 相似文献