全文获取类型
收费全文 | 793篇 |
免费 | 47篇 |
国内免费 | 2篇 |
专业分类
电工技术 | 13篇 |
综合类 | 2篇 |
化学工业 | 186篇 |
金属工艺 | 14篇 |
机械仪表 | 16篇 |
建筑科学 | 9篇 |
矿业工程 | 1篇 |
能源动力 | 22篇 |
轻工业 | 83篇 |
水利工程 | 3篇 |
石油天然气 | 7篇 |
无线电 | 95篇 |
一般工业技术 | 149篇 |
冶金工业 | 156篇 |
原子能技术 | 22篇 |
自动化技术 | 64篇 |
出版年
2023年 | 16篇 |
2022年 | 16篇 |
2021年 | 37篇 |
2020年 | 16篇 |
2019年 | 13篇 |
2018年 | 25篇 |
2017年 | 24篇 |
2016年 | 30篇 |
2015年 | 26篇 |
2014年 | 28篇 |
2013年 | 38篇 |
2012年 | 43篇 |
2011年 | 42篇 |
2010年 | 27篇 |
2009年 | 31篇 |
2008年 | 21篇 |
2007年 | 29篇 |
2006年 | 28篇 |
2005年 | 21篇 |
2004年 | 24篇 |
2003年 | 6篇 |
2002年 | 21篇 |
2001年 | 10篇 |
2000年 | 20篇 |
1999年 | 12篇 |
1998年 | 58篇 |
1997年 | 36篇 |
1996年 | 26篇 |
1995年 | 21篇 |
1994年 | 10篇 |
1993年 | 10篇 |
1992年 | 5篇 |
1991年 | 4篇 |
1990年 | 2篇 |
1989年 | 3篇 |
1987年 | 2篇 |
1986年 | 5篇 |
1985年 | 6篇 |
1984年 | 7篇 |
1983年 | 4篇 |
1981年 | 3篇 |
1979年 | 3篇 |
1977年 | 3篇 |
1976年 | 16篇 |
1975年 | 5篇 |
1974年 | 1篇 |
1973年 | 2篇 |
1972年 | 1篇 |
1971年 | 1篇 |
1965年 | 2篇 |
排序方式: 共有842条查询结果,搜索用时 15 毫秒
1.
2.
3.
研究结果表明 :水胶比、胶凝材料用量、钢纤维掺量、矿渣代水泥量对钢纤维砼强度影响显著。当矿渣取代水泥 10 %时 ,钢纤维砼强度最高。经试验选择出一个具有良好和易性和较高强度 (118MPa)的钢纤维砼配合比 ,为掺磨细矿渣的中含量超短异形钢纤维砼的设计和施工提供了试验依据 相似文献
4.
External Synchronization of 160-GHz Optical Beat Signal by Optical Phase-Locked Loop Technique 总被引:1,自引:0,他引:1
We have synchronized a 160-GHz optical beat signal with a 40-GHz reference optical pulse train by using an optical phase-locked loop (OPLL). The OPLL consists of an optical beat signal source, comprising a pair of three-electrode distributed feedback laser diodes that works as a voltage controlled oscillator, and an all-optical phase detector based on the two-photon absorption in a silicon avalanche photodiode. Phase-locking operation is confirmed through phase-error measurement and cross-correlation trace measurement. The residual timing jitter of the 160-GHz optical beat signal relative to the reference pulse train, in the bandwidth of 80 MHz, is measured to be as small as 126 fs 相似文献
5.
Automated camerawork for capturing desktop presentations 总被引:1,自引:0,他引:1
Ozeki M. Nakamura Y. Ohta Y. 《Vision, Image and Signal Processing, IEE Proceedings -》2005,152(4):437-447
A novel automated camera control method for capturing desktop presentations is introduced. Typical features and the camerawork of shots that appear frequently in TV programs are discussed. To realise those features in this automated video capturing system, the purpose of camerawork is classified from two points of view: target and aspect-of-target. Then, the correspondence between the classification and typical shots and camerawork is considered. A virtual-frame control algorithm based on this idea is proposed, and its implementation in a video production system. Results are shown that verify this method through two kinds of experiments, virtual video capturing using CG animations and real video capturing of real presentations. 相似文献
6.
An alternating dispersion arrangement is proposed for soliton systems with dispersion compensation to improve soliton stabilisation. A transmission experiment at 20 Gbit/s over 2600 km long singlemode fibre was successfully demonstrated by employing this novel dispersion arrangement 相似文献
7.
Osteoclastic features of multinucleated giant cells responding to synthetic hydroxyapatite implanted in rat jaw bone. 总被引:2,自引:0,他引:2
N Takeshita T Akagi M Yamasaki T Ozeki T Nojima Y Hiramatsu N Nagai 《Journal of electron microscopy》1992,41(3):141-146
Multinucleated giant cells (MGCs) that responded to synthetic hydroxyapatite (HAP) implanted in rat mandibles were studied with electron microscopy. HAP used in this study sintered at 200 degrees C (HAP200) and at 125 degrees C (HAP1250) after the synthesis by a wet method. One to three weeks after the intraosseous implantation of HAP, MGCs responding to HAP200 had not only well-developed ruffled border and the clear zone but well-developed perinuclear Golgi complex, many mitochondria and vesicles in their cytoplasms. MGCs responding to HAP1250 had the clear zone, but not the ruffled border although they showed similar cytoplasmic features to those of MGCs responding to HAP200. They merely extended short slender cytoplasmic processes to HAP1250. These results suggest that although osteoclast-like MGCs respond to HAP implanted in the bone, the development of the ruffled border-clear zone system depends on physicochemical properties of HAP. 相似文献
8.
The authors tried to find the correlation between the occurrence of genital tract candidiasis in adolescents and some subjective and objective examination parameters. The highest correlation rates were found for pudendal pruritus, lower abdominal pains and early applied antibiotic therapy material: 188 adolescent girls. 相似文献
9.
T Saito S Kurumada Y Kawakami H Go T Uchiyama K Ueki 《Canadian Metallurgical Quarterly》1996,56(2):105-106
A modified surgical splint for Le Fort I osteotomies with transverse expansion is presented. The splint is made of a transpalatal stainless steel bar with acrylic abutment against the palatal surface of the molar and bicuspid tooth. It is rigid and renders excellent retention. It causes minimal patient discomfort, and oral hygiene is hardly compromised. 相似文献
10.
Verrucous carcinoma is a variant of squamous cell carcinoma and should be distinguished from benign papilloma and well-differentiated nonverrucous squamous cell carcinoma. It is rare tumor of the sinonasal tract. Occasionally, conventional squamous cell carcinomatous components may be seen in verrucous carcinoma. This entity is called a hybrid verrucous squamous cell carcinoma. We report a case of hybrid verrucous squamous cell carcinoma occurring in the nasal cavity and paranasal sinus of a 67-year-old male. The removed mass shows the typical feature of verrucous carcinoma, but focally conventional squamous cell carcinomatous area is also noted. The treatment of this case follows verrucous carcinoma, but close follow up is mandatory because it may potentially spread to regional lymph nodes in contrast to pure form of verrucous carcinoma. 相似文献