全文获取类型
收费全文 | 2648篇 |
免费 | 121篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 24篇 |
综合类 | 3篇 |
化学工业 | 658篇 |
金属工艺 | 48篇 |
机械仪表 | 44篇 |
建筑科学 | 77篇 |
矿业工程 | 4篇 |
能源动力 | 45篇 |
轻工业 | 370篇 |
水利工程 | 43篇 |
石油天然气 | 2篇 |
无线电 | 146篇 |
一般工业技术 | 355篇 |
冶金工业 | 671篇 |
原子能技术 | 27篇 |
自动化技术 | 253篇 |
出版年
2023年 | 24篇 |
2022年 | 54篇 |
2021年 | 131篇 |
2020年 | 68篇 |
2019年 | 56篇 |
2018年 | 68篇 |
2017年 | 83篇 |
2016年 | 76篇 |
2015年 | 45篇 |
2014年 | 76篇 |
2013年 | 143篇 |
2012年 | 123篇 |
2011年 | 135篇 |
2010年 | 101篇 |
2009年 | 88篇 |
2008年 | 102篇 |
2007年 | 111篇 |
2006年 | 103篇 |
2005年 | 72篇 |
2004年 | 72篇 |
2003年 | 44篇 |
2002年 | 57篇 |
2001年 | 31篇 |
2000年 | 43篇 |
1999年 | 47篇 |
1998年 | 100篇 |
1997年 | 85篇 |
1996年 | 80篇 |
1995年 | 54篇 |
1994年 | 40篇 |
1993年 | 51篇 |
1992年 | 19篇 |
1991年 | 21篇 |
1990年 | 22篇 |
1989年 | 26篇 |
1988年 | 15篇 |
1986年 | 15篇 |
1985年 | 28篇 |
1984年 | 14篇 |
1983年 | 19篇 |
1982年 | 18篇 |
1981年 | 19篇 |
1980年 | 15篇 |
1979年 | 16篇 |
1978年 | 13篇 |
1977年 | 11篇 |
1976年 | 23篇 |
1975年 | 21篇 |
1974年 | 13篇 |
1973年 | 10篇 |
排序方式: 共有2770条查询结果,搜索用时 31 毫秒
1.
2.
Ricardo Cambraia Parreira Diana Paola Gmez‐Mendoza Itamar Couto Guedes de Jesus Rafael Pereira Lemos Anderson Kennedy Santos Cristiana Perdigo Rezende Henrique Csar Pereira Figueiredo Mauro Cunha Xavier Pinto Frank Kjeldsen Silvia Guatimosim Rodrigo Ribeiro Resende Thiago Verano‐Braga 《Proteomics. Clinical applications》2020,14(4)
3.
Nicolas Guerda; DeSilva Angela M.; Grey Kathleen S.; Gonzalez-Eastep Diana 《Canadian Metallurgical Quarterly》2006,37(6):702
Currently, ethnic and racial minority individuals represent a large proportion of the U.S. population, and researchers expect that they will represent the majority of the population by 2050. This shift in U.S. demographics calls for a greater awareness and integration of cultural issues into the assessment and treatment of ethnically and linguistically diverse clients. This article examines the unique beliefs and manifestations of illnesses among Haitians in connection with the American Psychological Association's (APA, 2002) Multicultural Guidelines. The authors use a common culture-bound syndrome, Séizisman, to illustrate the cultural beliefs, assessment, and treatment of illnesses among Haitians. In so doing, they demonstrate how to incorporate the APA Multicultural Guidelines into treatment with clients of diverse cultural and racial backgrounds. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
4.
Comments on the argument of L. T. Hoshmand and D. E. Polkinghorn (see record 1992-21300-001) that psychological practice should inform science to the same degree that science informs practice. Based on a survey of 121 faculty members in programs accredited by the American Psychological Association, 65% reported practice activity. The authors agree that the problem involves a much more complex integrative task that goes beyond simply recognizing knowledge gained in practice settings as valid. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
5.
6.
A recently proposed argument to explain the improved performance of the eight-point algorithm that results from using normalized
data (Chojnacki, W., et al. in IEEE Trans. Pattern Anal. Mach. Intell. 25(9):1172–1177, 2003) relies upon adoption of a certain model for statistical data distribution. Under this model, the cost function that underlies
the algorithm operating on the normalized data is statistically more advantageous than the cost function that underpins the
algorithm using unnormalized data. Here we extend this explanation by introducing a more refined, structured model for data
distribution. Under the extended model, the normalized eight-point algorithm turns out to be approximately consistent in a
statistical sense. The proposed extension provides a link between the existing statistical rationalization of the normalized
eight-point algorithm and the approach of Mühlich and Mester for enhancing total least squares estimation methods via equilibration.
The paper forms part of a wider effort to rationalize and interrelate foundational methods in vision parameter estimation. 相似文献
7.
Luginbuhl P. Collins S.D. Racine G.-A. Gretillat M.-A. De Rooij N.F. Brooks K.G. Setter N. 《Journal of microelectromechanical systems》1997,6(4):337-346
The fabrication using silicon micromachining and characterization of an acoustic Lamb wave actuator is presented. The intended use of the device is for mass transport and sensor applications. The device consists of dual interdigitated transducers patterned on a thin-film composite membrane of silicon nitride, platinum, and a sol-gel-derived piezoelectric ceramic (PZT) thin film. The acoustic properties of the device are presented along with preliminary applications to mechanical transport and liquid delivery systems. Improved acoustic signals and improved mass transport are achieved with PZT over present Lamb wave devices utilizing ZnO or AlN as the piezoelectric transducer 相似文献
8.
Berninger Virginia W.; Vaughan Katherine; Abbott Robert D.; Brooks Allison; Abbott Sylvia P.; Rogan Laura; Reed Elizabeth; Graham Steve 《Canadian Metallurgical Quarterly》1998,90(4):587
Poor spellers in 2nd grade (n?=?128) participated in 24 20-min sessions that included (a) direct instruction in the alphabet principle (most frequent phoneme-spelling connections); (b) modeling of different approaches, singly and in combination, for developing connections between spoken and written words for 48 words ordered by sound-spelling predictability; and (c) practice in composing. Results of this multilayered intervention showed that (a) more than 1 way of developing sound-spelling connections is effective in teaching spelling but that after training in the alphabet principle, combining whole word and onset-rime training is most effective in achieving transfer of the alphabet principle across word contexts; (b) functional spelling units of not only a single letter but also 2 or more letters are important in beginning spelling; and (c) training in spelling transfers to composition and word recognition. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
9.
Francis E. Powell Brian W. Brooks 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》1993,57(1):65-71
Dimensionless material balance equations describing an uninhibited enzyme hydrolysis process in a semi-batch reactor (i.e. fed-batch reactor) are formulated; numerical solution of these equations provided concentration profiles of the enzyme-substrate complex by using published kinetic parameters. The unrestricted values obtained are compared with estimates based separately on the reaction steady state and stationary state assumptions. Results are discussed in terms of the enzyme/substrate inventory used and it is found that the reaction steady state is a satisfactory approximation only when this ratio is sufficiently small. The stationary state may be a better approximation at other values, particularly when enzyme is added to substrate or when an empty tank is being filled. Reaction yields from semi-batch and batch operations are compared. Processing takes longer in the semi-batch operations and complete conversions are only practical in this mode when enzyme is added to substrate. 相似文献
10.
Detailed representations of the reactor core generate computational meshes with a high number of cells where the fluid dynamics equations must be solved. An exhaustive analysis of the CPU times needed by the thermal-hydraulic subchannel code COBRA-TF for different stages in the solution process has revealed that the solution of the linear system of pressure equations is the most time consuming process. To improve code efficiency two optimized matrix solvers, Super LU library and Krylov non-stationary iterative methods have been implemented in the code and their performance has been tested using a suite of five test cases. The results of performed comparative analyses have demonstrated that for large cases, the implementation of the Bi-Conjugate Gradient Stabilized (Bi-CGSTAB) Krylov method combined with the incomplete LU factorization with dual truncation strategy (ILUT) pre-conditioner reduced the time used by the code for the solution of the pressure matrix by a factor of 20. Both new solvers converge smoothly regardless of the nature of simulated cases and the mesh structures and improve the stability and accuracy of results compared to the classic Gauss–Seidel iterative method. The obtained results indicate that the direct inversion method is the best option for small cases. 相似文献