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411.
Understanding the association between computer use and adult cognition has been limited until now by self-selected samples with restricted ranges of age and education. Here we studied effects of computer use in a large national sample (N = 2,671) of adults aged 32–84, assessing cognition with the Brief Test of Adult Cognition by Telephone (Tun & Lachman, 2005) and executive function with the Stop and Go Switch Task (Tun & Lachman, 2008). Frequency of computer activity was associated with cognitive performance after controlling for age, sex, education, and health status: That is, individuals who used the computer frequently scored significantly higher than those who seldom used the computer. Greater computer use was also associated with better executive function on a task-switching test, even after controlling for basic cognitive ability as well as demographic variables. These findings suggest that frequent computer activity is associated with good cognitive function, particularly executive control, across adulthood into old age, especially for those with lower intellectual ability. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
412.
A Mannelli D Fish TJ Daniels I Kharitonenkov H Tun AC Cozzolino DJ Bucher 《Canadian Metallurgical Quarterly》1997,20(4):355-359
We have shown that activated partial thromboplastin time values in children are considerably longer than in adults, but the causes for this observation remained unclear. Therefore, we investigated the correlation between activated partial thromboplastin time values and concentrations of clotting factors, quotients and titers of the tissue thromboplastin inhibition test, and antiphospholipid antibodies in healthy children, children with recurrent infections, and adults. Concentrations of factors VIII, IX, and HMWK were significantly lower in children than in adults. Simple linear regression analysis failed to show a correlation between the concentration of a single clotting factor and the activated partial thromboplastin time values. No significant correlation was found between activated partial thromboplastin time and elevation of the tissue thromboplastin inhibition test quotients or titers, or antiphospholipid antibodies values. The determined activated partial thromboplastin time was best described by a function including all measured coagulation factors. Our study suggests, that no single clotting factor or lupus anticoagulants are responsible for the longer activated partial thromboplastin time in healthy children, but that activated partial thromboplastin prolongation is caused by the combination of several slightly lower clotting factors. 相似文献
413.
414.
详细分析了<中国图书馆分类法>中图书分类编目的树形结构,如何将这种树形结构的数据写入TreeView拉件中,以及程序的改进优化方法. 相似文献
415.
Wei Yu Jing Li Tun Seng Herng Zishen Wang Xiaoxu Zhao Xiao Chi Wei Fu Ibrahim Abdelwahab Jun Zhou Jiadong Dan Zhongxin Chen Zhi Chen Zejun Li Jiong Lu Stephen J. Pennycook Yuan Ping Feng Jun Ding Kian Ping Loh 《Advanced materials (Deerfield Beach, Fla.)》2019,31(40)
Among van der Waals layered ferromagnets, monolayer vanadium diselenide (VSe2) stands out due to its robust ferromagnetism. However, the exfoliation of monolayer VSe2 is challenging, not least because the monolayer flake is extremely unstable in air. Using an electrochemical exfoliation approach with organic cations as the intercalants, monolayer 1T‐VSe2 flakes are successfully obtained from the bulk crystal at high yield. Thiol molecules are further introduced onto the VSe2 surface to passivate the exfoliated flakes, which improves the air stability of the flakes for subsequent characterizations. Room‐temperature ferromagnetism is confirmed on the exfoliated 2D VSe2 flakes using a superconducting quantum interference device (SQUID), X‐ray magnetic circular dichroism (XMCD), and magnetic force microscopy (MFM), where the monolayer flake displays the strongest ferromagnetic properties. Se vacancies, which can be ubiquitous in such materials, also contribute to the ferromagnetism of VSe2, although density functional theory (DFT) calculations show that such effect can be minimized by physisorbed oxygen molecules or covalently bound thiol molecules. 相似文献
416.
Appearance-based methods have been proven to be useful for face recognition tasks. The main problem with appearance-based methods originates from the multimodality of face images. It is known that images of different people in the original data space are more closely located to each other than those of the same person under different imaging conditions. In this paper, we propose a novel approach based on the nonlinear manifold embedding to define a linear subspace for illumination variations. This embedding based framework utilizes an optimization scheme to calculate the bases of the subspace. Since the optimization problem does not rely on the physical properties of the factor, the framework can also be used for other types of factors such as pose and expression. We obtained some promising recognition results under changing illumination conditions. Our error rates are comparable with state of art methods. 相似文献
417.
Poly(N‐isopropylacrylamide) (NIPAAm) is well known as a smart material with good thermal sensitivity and favorable biocompatibility. A series of new smart hydrogels, NIPAAm copolymerized with IAM (itaconamic acid; 4‐amino‐2‐methylene‐4‐oxobutanoic acid), were synthesized through radical solution polymerization in this work. Poly(NIPAAm‐co‐IAM) can respond to the changes of temperature as well as pH value. Such a characteristic is due to the fact that IAM contains not only a hydrophilic acrylic acid moiety but also an acrylamide moiety to be thermal and pH sensitive. The experimental results show that the lower critical solution temperature (LCST) of the copolymer increases as the molar fraction of IAM increases. Moreover, based on the current experimental data, 3 wt % of Poly(NIPAAm‐co‐IAM) aqueous solution in this study exhibits a phase transition temperature (37.8°C) close to the human body temperature in the buffer solution of pH 7 possibly to be useful in drug delivery. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42367. 相似文献
418.
Image analysis methods are widely used tools for an objective pilling evaluation. However, due to their intrinsic limitations, simple image analysis of digital photographs is not a suitable procedure for the pilling evaluation of fabrics with complex structures and distinct patterns. Generally, a fabric pattern or a complex fabric structure have presented significant problem to the pills detection. This paper describes a system of the objective pilling evaluation of unicolor fabrics and even fabrics with complex patterns. The main points of the pilling evaluation system include a 3D fabric surface reconstruction from shading based on gradient field method, using image analysis tools for the pills detection and an estimation of an objective pilling grade. In order to enable the estimation of the objective pilling grade, a relationship between the pilling grades obtained by a subjective method and selected pill characteristics was specified using a linear regression model. The method was tested on a set of different fabrics and estimated pilling grades were compared with subjective pilling grades of the samples. Results showed that the proposed method is suitable and reliable tool for the objective pilling evaluation of various types of fabrics. 相似文献
419.
在对带 TLD 的高层建筑风振响应问题系统研究基础上,建立了运动方程,用第一振型将主体结构展开,针对所得方程为非经典阻尼和非对称结构以及脉动风谱为非有理分式风谱的情况,用线性滤波过程生成脉动风谱,用复模态理论和扩阶法进行解耦,获得了等效风谱对应的以第一振型表示的结构风振响应解析解.该方法可用于带 TLD 结构的风振与抗风可靠度分析以及基于可靠度约束的抗风优化设计. 相似文献
420.