全文获取类型
收费全文 | 3126篇 |
免费 | 206篇 |
国内免费 | 7篇 |
专业分类
电工技术 | 51篇 |
综合类 | 19篇 |
化学工业 | 698篇 |
金属工艺 | 89篇 |
机械仪表 | 74篇 |
建筑科学 | 273篇 |
矿业工程 | 24篇 |
能源动力 | 98篇 |
轻工业 | 159篇 |
水利工程 | 28篇 |
石油天然气 | 2篇 |
无线电 | 240篇 |
一般工业技术 | 685篇 |
冶金工业 | 192篇 |
原子能技术 | 12篇 |
自动化技术 | 695篇 |
出版年
2024年 | 5篇 |
2023年 | 66篇 |
2022年 | 90篇 |
2021年 | 119篇 |
2020年 | 107篇 |
2019年 | 102篇 |
2018年 | 123篇 |
2017年 | 96篇 |
2016年 | 149篇 |
2015年 | 135篇 |
2014年 | 156篇 |
2013年 | 225篇 |
2012年 | 237篇 |
2011年 | 271篇 |
2010年 | 176篇 |
2009年 | 169篇 |
2008年 | 165篇 |
2007年 | 168篇 |
2006年 | 102篇 |
2005年 | 89篇 |
2004年 | 79篇 |
2003年 | 55篇 |
2002年 | 69篇 |
2001年 | 32篇 |
2000年 | 29篇 |
1999年 | 29篇 |
1998年 | 43篇 |
1997年 | 42篇 |
1996年 | 27篇 |
1995年 | 20篇 |
1994年 | 17篇 |
1993年 | 19篇 |
1992年 | 17篇 |
1991年 | 14篇 |
1990年 | 11篇 |
1989年 | 4篇 |
1988年 | 6篇 |
1987年 | 3篇 |
1986年 | 3篇 |
1985年 | 11篇 |
1984年 | 11篇 |
1983年 | 10篇 |
1981年 | 4篇 |
1980年 | 3篇 |
1979年 | 4篇 |
1978年 | 4篇 |
1977年 | 3篇 |
1976年 | 3篇 |
1975年 | 4篇 |
1961年 | 2篇 |
排序方式: 共有3339条查询结果,搜索用时 15 毫秒
1.
2.
Emmanuel. Delamarche Bruno. Michel Hans A. Biebuyck Christoph Gerber 《Advanced materials (Deerfield Beach, Fla.)》1996,8(9):719-729
Self-assembled monolayers (SAMs) of alkanethiols and disulfides on gold form organic interfaces with properties largely controlled by the end groups of the molecules composing the film. SAMs provide a unique link between the science of organic surfaces and technologies that seek to exploit their adaptable character. Many techniques are useful for probing the structure of SAMs although only scanning tunneling microscopy (STM) at picoamperes reveals the details of the packing of their end groups at the sub-angstrom level. This review demonstrates that STM effectively tests new types of control over the microscopic structure–property relationships characteristic of SAMs on gold that should prove useful to their application. 相似文献
3.
Karin Metz Stephanie Fl?ter Christoph Kr?ger Carolin Donath Daniela Piontek Sabine Gradl 《Nicotine & tobacco research》2007,9(8):853-863
Smokers with smoking-related diseases who are hospitalized in rehabilitation centers should be offered smoking cessation. This is the first study evaluating whether telephone booster sessions after intensive inpatient treatment are an effective strategy. The present study was conducted in 13 rehabilitation centers for somatic disorders as a prospective multicenter study with a randomized treatment-control group design. We compared abstinence rates after hospital discharge from treatment that included a group smoking cessation program with (treatment group) and without telephone booster sessions (control group). Data from 290 smokers were analyzed. After 6 and 12 months the treatment group achieved abstinence rates twice as high as those of the control group. Men profited more from telephone booster sessions than did women. Results indicated that telephone booster sessions were highly effective (even) after an inherently intensive group program during a hospital stay. Further research should focus on the special needs of women receiving telephone counseling. 相似文献
4.
Goldman Susan R.; Mertz Davis L.; Pellegrino James W. 《Canadian Metallurgical Quarterly》1989,81(4):481
Practice on addition basic facts and changes in solution strategies were examined in 3rd- and 4th-grade students, practicing over 3 months. Response latencies decreased, indicating positive practice effects. Each of 3 student groups demonstrated different solution–strategy mixtures. Different mixtures led to different practice effects, indexed by shifts to more efficient counting strategies and more direct retrieval. Expectations about effects of practice and instructional strategies for optimizing practice must be sensitive to a child's actual strategy pattern. Most students had decreasing latency practice functions. However, quantitative functions fit to the practice session data indicated a high proportion of cases where the latency pattern over sessions was nonmonotonic. Trends over a small number of practice sessions may be inadequate for decisions about the utility of further practice, because such data may poorly represent long-term, cumulative effects on modifying strategy usage. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
5.
6.
Ingo Alig Dirk Lellinger Harald Oehler Sergey A. Adamovsky Christoph Schick 《Progress in Organic Coatings》2008,61(2-4):166-175
A new microcalorimeter with eight parallel channels using robust, low cost sensors for characterization of coatings and adhesives is described and first experiments on coatings and adhesives are presented. The calorimetric sensors are based on thin glass plates (20 mm × 20 mm, thickness 150 μm) with heater and thermocouple sputtered on the surfaces (calorimetric active area of about 9 mm2). The setup allows heating and cooling experiments as well as isothermal measurements in the temperature-modulated mode with up to eight sensors in parallel. The measured quantities are the real (C′p) and imaginary part (C″p) of the complex heat capacity (), the related absolute value of the heat capacity () and the heat flow . An industrial computer (NI PXI system) with specific software for calibration and data recording controls the electronic components. Sensors can be embedded in a temperature controlled oven (heating and cooling by Peltier elements) or alternatively in a climatic cabinet with controlled temperature and humidity.
The method has been applied successfully to monitoring of film formation of aqueous polymer dispersions (styrene-acrylate copolymer) and curing of coatings. 相似文献
7.
Christoph Böhringer Wolfgang Wiegard Collin Starkweather Anna Ruocco 《Computational Economics》2003,22(1):75-109
The double or even triple dividend hypothesis of green tax reforms has beena major issue of dispute in both the scientific community and the politicalarena during the last decade. Theoretical analysis has provided a number ofimportant qualitative insights to the debate but lacks of actual policyrelevance due to very restrictive assumptions. Applied research that takes thestep from stylized analytical to complex numerical models usually comes as ablackbox to non-expert modelers. This paper aims at bridging the gap betweenstylized theoretical work and numerical analysis. We develop a flexible,interactive simulation model which is accessible underhttp://brw.zew.de. Users can specify their own green tax reforms andevaluate the induced economic and environmental effects. Based on illustrativesimulations, we demonstrate the usefulness of our do-it-yourself approach fora better understanding of the double (triple) dividend hypothesis. 相似文献
8.
9.
10.
We examined 21 patients aged 5 months to 19 years, on a 1.5 T magnet. T1-weighted spin-echo images, proton density and T2-weighted images with spin-echo and turbo spin-echo sequences, and contrast-enhanced magnetization transfer (MT) T1-weighted images were obtained in all cases. MT T1-weighted images were performed before injection in 9 patients. Subependymal nodules were found in 14, and cortical and subcortical tubers in 20 of the 21 patients. MT T1-weighted images showed tubers and subependymal nodules as higher signal than normal gray matter and revealed more tubers than conventional sequences in 11 cases. High signal intensity lesions of the white matter were found in 19 patients but were seen only on MT images in 9 cases. When MT images both before and after injection were available, tubers and white matter lesions were more easily recognised on unenhanced MT images because of their higher contrast. 相似文献