全文获取类型
收费全文 | 8086篇 |
免费 | 124篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 140篇 |
综合类 | 4篇 |
化学工业 | 904篇 |
金属工艺 | 109篇 |
机械仪表 | 146篇 |
建筑科学 | 180篇 |
矿业工程 | 33篇 |
能源动力 | 108篇 |
轻工业 | 707篇 |
水利工程 | 42篇 |
石油天然气 | 22篇 |
无线电 | 807篇 |
一般工业技术 | 1008篇 |
冶金工业 | 3164篇 |
原子能技术 | 109篇 |
自动化技术 | 728篇 |
出版年
2021年 | 55篇 |
2020年 | 38篇 |
2019年 | 47篇 |
2018年 | 53篇 |
2017年 | 61篇 |
2016年 | 80篇 |
2015年 | 62篇 |
2014年 | 89篇 |
2013年 | 197篇 |
2012年 | 169篇 |
2011年 | 241篇 |
2010年 | 205篇 |
2009年 | 218篇 |
2008年 | 232篇 |
2007年 | 244篇 |
2006年 | 205篇 |
2005年 | 206篇 |
2004年 | 189篇 |
2003年 | 168篇 |
2002年 | 144篇 |
2001年 | 148篇 |
2000年 | 166篇 |
1999年 | 209篇 |
1998年 | 743篇 |
1997年 | 459篇 |
1996年 | 375篇 |
1995年 | 235篇 |
1994年 | 216篇 |
1993年 | 265篇 |
1992年 | 151篇 |
1991年 | 145篇 |
1990年 | 141篇 |
1989年 | 160篇 |
1988年 | 143篇 |
1987年 | 116篇 |
1986年 | 138篇 |
1985年 | 124篇 |
1984年 | 89篇 |
1983年 | 89篇 |
1982年 | 81篇 |
1981年 | 67篇 |
1980年 | 67篇 |
1979年 | 78篇 |
1978年 | 81篇 |
1977年 | 112篇 |
1976年 | 178篇 |
1975年 | 60篇 |
1974年 | 56篇 |
1973年 | 54篇 |
1972年 | 37篇 |
排序方式: 共有8211条查询结果,搜索用时 31 毫秒
21.
Lash Steven J.; Stephens Robert S.; Burden Jennifer L.; Grambow Steven C.; DeMarce Josephine M.; Jones Mark E.; Lozano Brian E.; Jeffreys Amy S.; Fearer Stephanie A.; Horner Ronnie D. 《Canadian Metallurgical Quarterly》2007,21(3):387
Although continuing care is strongly related to positive treatment outcomes for substance use disorder (SUD), participation rates are low and few effective interventions are available. In a randomized clinical trial with 150 participants (97% men), 75 graduates of a residential Veterans Affairs Medical Center SUD program who received an aftercare contract, attendance prompts, and reinforcers (CPR) were compared to 75 graduates who received standard treatment (STX). Among CPR participants, 55% completed at least 3 months of aftercare, compared to 36% in STX. Similarly, CPR participants remained in treatment longer than those in STX (5.5 vs. 4.4 months). Additionally, CPR participants were more likely to be abstinent compared to STX (57% vs. 37%) after 1 year. The CPR intervention offers a practical means to improve adherence among individuals in SUD treatment. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
22.
23.
Zhongde Wang Jullien G.A. Miller W.C. Jinghong Wang Bizzan S.S. 《Solid-State Circuits, IEEE Journal of》1997,32(2):206-214
Using an enhanced multiple output domino logic (EMODL) implementation of a carry lookahead adder (CLA), sums of several consecutive bits can be built in one nFET tree with a single carry-in. Based on this result, a new sparse carry chain architecture is proposed for the CLA adder. We demonstrate the design approach using a 32-b adder, and show that only four carries are sufficient for generating all sums, with a consequent reduction in the number of stage delays. Using a 1.2-μm CMOS technology, we verify our simulation procedures by fabrication and measurement of a 2.7 ns critical path 相似文献
24.
V Kumar PM Carabateas JA Dority WG Earley JP Mallamo C Subramanyam LD Aimone B Ault DL DeHaven Hudkins MS Miller 《Canadian Metallurgical Quarterly》1995,38(10):1826-1830
Replacement of the pyridinium ring of 6,11-ethanobenzo[b]quinolizinium cations with thiazolium (4a and 4b) and N-methylimidazolium (4c and 4d) resulted in equipotent compounds in the [3H]TCP binding assay. The corresponding N-methyl-1,2,4-triazolium analogs were less potent in this assay. The thiazolium derivative 4b, with a Ki = 2.9 nM, is being evaluated as a possible neuroprotective N-methyl-D-aspartic acid (NMDA) antagonist. 相似文献
25.
The centerline velocity profiles obtained from the solution of the two- and three-dimensional representations of the lid driven cavity flow problem are compared for different Reynolds numbers. Two configurations were used in this study: a unit cavity and a cavity with an aspect ratio of 2. The Reynolds numbers ranged from 100 to 5000 for all of the configurations studied. A new method of extending the Jacobi collocation technique called spectral difference is developed in this paper together with a unique computational grid. In addition, an iterative method for solving the pressure problem is also developed. This new numerical method allowed the calculation of three-dimensional Navier-Stokes equations to be performed in computers with very modest computational capabilities such as workstations. 相似文献
26.
27.
The object-oriented approach to integrating knowledge data, and models is examined. Under the object-oriented paradigm, everything is an object, which is itself an encapsulation of data and methods to manipulate and access the data within the object. Thus knowledge, data, and models can be defined as special kinds of objects. Active knowledge/data language (KDL), a functional object-oriented database system is considered, covering the active-KDL-type system and functions, and query-driven simulation 相似文献
28.
29.
30.
P. F. Miller H. A. Gebbie 《Journal of Infrared, Millimeter and Terahertz Waves》1996,17(10):1573-1591
Measurements made in an untuned resonator by Fourier Transform Spectroscopy of atmospheric aerosols are explained by a pumped phonon model due to Fröhlich. 相似文献