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961.
Convective heat transfer within circular microchannels in a rectangular solid substrate with heat generation due to imposed
magnetic field was studied. A detailed parametric study was performed by varying Reynolds number, magnetic field strength,
working fluid, and the diameter of the channel. It was found that the heat transfer coefficient decreases downstream along
the channel. Nusselt number increased with Reynolds number. The tube diameter, properties of the working fluid, and magnetic
field strength affected the temperature distribution and heat transfer rate at the solid-fluid interface. 相似文献
962.
Upscaled Unstructured Computational Grids for Efficient Simulation of Flow in Fractured Porous Media
Muhammad Sahimi R. Darvishi Manouchehr Haghighi M. Reza Rasaei 《Transport in Porous Media》2010,83(1):195-218
Discrete fracture modeling (DFM) is currently the most promising approach for modeling of naturally fractured reservoirs and
simulation of multiphase fluid flow therein. In contrast with the classical double-porosity/double permeability models, in
the DFM approach all the interactions and fluid flow in and between the fractures and within the matrix are modeled in a unified
manner, using the same computational grid. There is no need for computing the shape factors, which are crucial to the accuracy
of the double-porosity models. We have exploited this concept in order to develop a new method for the generation of unstructured
computational grids. In the new approach the geological model (GM) of the reservoir is first generated, using square or cubic
grid blocks. The GM is then upscaled using a method based on the multiresolution wavelet transformations that we recently
developed. The upscaled grid contains a distribution of the square or cubic blocks of various sizes. A map of the blocks’
centers is then used with an optimized Delauney triangulation method and the advancing-front technique, in order to generate
the final unstructured triangulated grid suitable for use in any general reservoir simulator with any number of fluid phases. The new method also includes an algorithm for generating fractures
that, contrary to the previous methods, does not require modifying their paths due to the complexities that may arise in spatial
distribution of the grid blocks. It also includes an effective partitioning of the simulation domain that results in large
savings in the computation times. The speed-up in the computations with the new upscaled unstructured grid is about three
orders of magnitude over that for the initial GM. Simulation of waterflooding indicates that the agreement between the results
obtained with the GM and the upscaled unstructured grid is excellent. The method is equally applicable to the simulations
of multiphase flow in unfractured, but highly heterogeneous, reservoirs. 相似文献
963.
The synthesis of α‐pyrazolylglycine derivatives(7a‐d) with different substituents, starting from glycine have been pre pared. The spectroscopy of intermediate compounds and the final amino acids have been discussed. 相似文献
964.
Hui Wen Nies Mohd Saberi Mohamad Zalmiyah Zakaria Weng Howe Chan Muhammad Akmal Remli Yong Hui Nies 《Entropy (Basel, Switzerland)》2021,23(9)
Artificial intelligence in healthcare can potentially identify the probability of contracting a particular disease more accurately. There are five common molecular subtypes of breast cancer: luminal A, luminal B, basal, ERBB2, and normal-like. Previous investigations showed that pathway-based microarray analysis could help in the identification of prognostic markers from gene expressions. For example, directed random walk (DRW) can infer a greater reproducibility power of the pathway activity between two classes of samples with a higher classification accuracy. However, most of the existing methods (including DRW) ignored the characteristics of different cancer subtypes and considered all of the pathways to contribute equally to the analysis. Therefore, an enhanced DRW (eDRW+) is proposed to identify breast cancer prognostic markers from multiclass expression data. An improved weight strategy using one-way ANOVA (F-test) and pathway selection based on the greatest reproducibility power is proposed in eDRW+. The experimental results show that the eDRW+ exceeds other methods in terms of AUC. Besides this, the eDRW+ identifies 294 gene markers and 45 pathway markers from the breast cancer datasets with better AUC. Therefore, the prognostic markers (pathway markers and gene markers) can identify drug targets and look for cancer subtypes with clinically distinct outcomes. 相似文献
965.
L. Vijayalakshmi V. Parthasarathi Bharat Varu Narasinh Dodia Anamik Shah 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(9):e401-e402
In the title compound, C23H15NO2, the naphthyl unit is planar and the benzopyran unit is nearly planar. These two moieties are inclined at an angle of 9.10 (6)° with respect to one another. 相似文献
966.
The Wittig and Aza-Wittig reactions have undergone tremendous development over the past 50 years in light of their potential in organic synthesis to construct carbon–carbon and carbon–nitrogen double bonds. In contrast, the development of the analogous phospha-Wittig reaction has only seen progress over the last 12 years. A phospha-Wittig process is one that uses phosphaylides to convert carbonyl compounds to new materials possessing phosphorus–carbon double bonds (phosphaalkenes). The phospha-Wittig reaction has evolved from initial work involving metal-assisted phospha-Wittig reactions to phospha-Wittig reactions, of terminal phosphinidene complexes to, more recently, free phosphanylidene-σ4-phosphoranes as phospha-Wittig reagents. The major developments in the phospha-Wittig reaction are highlighted and divided into these three methodologies. The complementary nature and the differences between the three approaches is also discussed. Finally, wherein applicable, comparisons between the Wittig reaction and the phospha-Wittig reaction are presented. 相似文献
967.
968.
Muhammad Treifi S. Olutunde Oyadiji Derek K.L. Tsang 《International Journal of Solids and Structures》2008,45(25-26):6468-6484
The fractal-like finite element method (FFEM) is used to compute the stress intensity factors (SIFs) for different configurations of cracked/notched plates subject to in-plane shear and bending loading conditions. In the FFEM, the large number of unknown variables in the singular region around a notch tip is reduced to a small set of generalised co-ordinates by performing a fractal transformation using global interpolation functions. The use of exact analytical solutions of the displacement field around a notch tip as the global interpolation functions reduces the computational cost significantly and neither post-processing technique to extract SIFs nor special singular elements to model the singular region are required. The results of numerical examples of various configurations of cracked/notched plates are presented and validated via published data. Also, new results for cracked/notched plate problems are presented. These results demonstrate the accuracy and efficiency of the FFEM to compute the SIFs for notch problems under in-plane shear and bending loading conditions. 相似文献
969.
970.