全文获取类型
收费全文 | 1666篇 |
免费 | 123篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 12篇 |
综合类 | 3篇 |
化学工业 | 597篇 |
金属工艺 | 23篇 |
机械仪表 | 25篇 |
建筑科学 | 56篇 |
矿业工程 | 4篇 |
能源动力 | 45篇 |
轻工业 | 305篇 |
水利工程 | 13篇 |
石油天然气 | 1篇 |
无线电 | 96篇 |
一般工业技术 | 243篇 |
冶金工业 | 223篇 |
原子能技术 | 9篇 |
自动化技术 | 135篇 |
出版年
2024年 | 5篇 |
2023年 | 30篇 |
2022年 | 94篇 |
2021年 | 134篇 |
2020年 | 68篇 |
2019年 | 58篇 |
2018年 | 58篇 |
2017年 | 83篇 |
2016年 | 68篇 |
2015年 | 43篇 |
2014年 | 55篇 |
2013年 | 111篇 |
2012年 | 101篇 |
2011年 | 110篇 |
2010年 | 84篇 |
2009年 | 73篇 |
2008年 | 77篇 |
2007年 | 80篇 |
2006年 | 68篇 |
2005年 | 43篇 |
2004年 | 42篇 |
2003年 | 22篇 |
2002年 | 28篇 |
2001年 | 12篇 |
2000年 | 19篇 |
1999年 | 14篇 |
1998年 | 18篇 |
1997年 | 19篇 |
1996年 | 18篇 |
1995年 | 18篇 |
1994年 | 13篇 |
1993年 | 18篇 |
1992年 | 8篇 |
1991年 | 5篇 |
1990年 | 4篇 |
1989年 | 8篇 |
1988年 | 3篇 |
1987年 | 4篇 |
1985年 | 11篇 |
1984年 | 7篇 |
1983年 | 7篇 |
1982年 | 5篇 |
1981年 | 7篇 |
1980年 | 4篇 |
1979年 | 7篇 |
1978年 | 3篇 |
1977年 | 3篇 |
1976年 | 5篇 |
1973年 | 3篇 |
1964年 | 2篇 |
排序方式: 共有1790条查询结果,搜索用时 19 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.
A Azzi D Boscoboinik S Clément D Marilley NK Ozer R Ricciarelli A Tasinato 《Canadian Metallurgical Quarterly》1997,57(4-5):507-514
The effects of alpha-tocopherol and beta-tocopherol have been studied in rat and human aortic smooth muscle cells. Alpha-tocopherol, but not beta-tocopherol, inhibited smooth muscle cell proliferation and protein kinase C in a dose-dependent manner, at concentrations ranging from 10 to 50 microM. Beta-tocopherol added simultaneously with alpha-tocopherol prevented both proliferation and protein kinase C inhibition. Protein kinase C inhibition was cell cycle-dependent and it was prevented by okadaic acid, a protein phosphatase inhibitor. Protein kinase C activity measured from aortas of cholesterol-fed rabbits was also inhibited by alpha-tocopherol. By using protein kinase C (PKC) isoform-specific inhibitors and immunoprecipitation reactions it was found that PKC-alpha was selectively inhibited by alpha-tocopherol. Further, an activation of protein phosphatase 2A by alpha-tocopherol was found, which caused PKC-alpha dephosphorylation and inhibition. Ultimately, this cascade of events at the level of cell signal transduction leads to the inhibition of smooth muscle cell proliferation. 相似文献
5.
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
6.
Diana Hurdowar-Castro Ioannis Tsanis Ilmar Simanovskis 《Journal of Great Lakes research》2007,33(1):232-252
A 3D transport model is used to perform a comparative analysis of several potential drinking water intakes located along the northwest shore of Lake Ontario between Toronto and Oshawa. The model is specifically used to assess each intake under both long- and short-term transport of a potential pollutant release from the Pickering Nuclear Generating Station and potential and actual pollutant releases from local land sources respectively. A model based on a 500 m grid resolution is calibrated using data collected in the aftermath of the 1992 tritium spill at the Pickering Nuclear Generation Station and subsequently used to simulate long-term transport. A model based on a 100 m grid resolution is verified using drogue studies and used to simulate short-term transport events. Both models are used to assess pollutant levels at each of nine potential intake locations under different wind scenarios and pollutant releases. Field data for the study included water quality and flow measurements from local sewers and rivers, and estimates of pollutant levels from the local waste water treatment plants. This paper describes the model setup for both the long-term and short-term transport models, calibration using field data, long-term transport modeling, short-term transport modeling, and the comprehensive analysis approach used to evaluate the nine potential intake locations proposed. Results indicated that four intakes in particular outperformed other intake locations by maintaining bottom pollutant levels within governmental standards and warning times that exceeded 20 hours. 相似文献
7.
Woodruff-Pak Diana S.; Li Yong-Tong; Kazmi Abbas; Kem William R. 《Canadian Metallurgical Quarterly》1994,108(3):486
A nicotinic cholinergic antagonist, mecamylamine (MEC), was administered to rabbits tested on eyeblink classical conditioning (EBCC) in the 750-msec delay paradigm for 10 90-trial sessions. Nicotinic receptors were measured in 3 brain regions in S treatment groups: paired conditioned stimulus–unconditioned stimulus (CS–UCS) presentations with (1) vehicle, young; (2) vehicle, older; (3) 0.5 mg/kg MEC, young; unpaired CS–UCS with (4) 0.5 mg/kg MEC, young; and (5) vehicle, young. Daily MEC injections disrupted acquisition in young rabbits (769 trials to learning criterion vs 323 trials for vehicle-treated young rabbits). MEC-treated young rabbits learned similarly to older rabbits. Brain nicotinic receptors were not affected by 10 daily MEC injections. To our knowledge, this experimental protocol, using a low MEC dose to selectively inhibit nicotinic cholinergic receptors, is the first to demonstrate a role for nicotinic cholinergic receptors in EBCC. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
8.
Rintala Diana H.; Young Mary Ellen; Hart Karen A.; Fuhrer Marcus J. 《Canadian Metallurgical Quarterly》1994,39(1):15
140 adults (aged 19–77 yrs) were randomly selected from a sampling frame of 661 persons with spinal cord injury. They completed a questionnaire assessing amount of social support, degree of reciprocity with supporters, and satisfaction with relationships with supporters; the Center for Epidemiologic Studies Depression Scale; a self-report version of the Functional Independence Measure; and the Craig Handicap Assessment and Reporting Technique. A physician assessed the degree of paralytic impairment by means of the ASIA Total Motor Index Score. Relationships in which the supporter gave more than the participant were associated with more satisfaction with the relationship and more social support. The number of reciprocal relationships was positively associated with more desirable outcomes in the handicap dimensions of mobility, occupation, social integration, and economic self-sufficiency. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
9.
R. Iris Bahar Dan Hammerstrom Justin Harlow William H. Joyner Jr. Clifford Lau Diana Marculescu Alex Orailoglu Massoud Pedram 《Computer》2007,40(1):25-33
Although nanoelectronics won't replace CMOS for some time, research is needed now to develop the architectures, methods, and tools to maximally leverage nanoscale devices and terascale capacity. Addressing the complementary architectural and system issues involved requires greater collaboration at all levels. The effective use of nanotechnology calls for total system solutions 相似文献
10.
Classical conditioning of the nictitating membrane-eyeblink response in young (age 7 mo) and older (age 36 mo) New Zealand white rabbits in a delay paradigm with 400-msec CS–unconditioned stimulus/stimuli (UCS) interval was examined for initial acquisition and retention. Older animals required significantly more acquisition trials to reach learning criterion. Age differences in acquisition were temporary. Older rabbits responded at a level comparable to that of young rabbits such that total performance over the 630 trials of acquisition was not different. Rabbits in the explicitly unpaired control groups exhibited no age differences in unconditioned response (UCR) amplitude or latency measures. 12- and 18-mo retests demonstrated no significant age effects on retention. Patterns of retention differed between age groups. Older rabbits required fewer trials to obtain the learning criterion at each phase of testing. Younger rabbits maintained a stable performance throughout training. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献