全文获取类型
收费全文 | 1524940篇 |
免费 | 26150篇 |
国内免费 | 6986篇 |
专业分类
电工技术 | 34254篇 |
综合类 | 6485篇 |
化学工业 | 271637篇 |
金属工艺 | 64113篇 |
机械仪表 | 42738篇 |
建筑科学 | 47062篇 |
矿业工程 | 11374篇 |
能源动力 | 50217篇 |
轻工业 | 117906篇 |
水利工程 | 15495篇 |
石油天然气 | 37288篇 |
武器工业 | 136篇 |
无线电 | 196392篇 |
一般工业技术 | 287947篇 |
冶金工业 | 170374篇 |
原子能技术 | 33792篇 |
自动化技术 | 170866篇 |
出版年
2021年 | 15583篇 |
2020年 | 11847篇 |
2019年 | 14625篇 |
2018年 | 14844篇 |
2017年 | 14040篇 |
2016年 | 21056篇 |
2015年 | 17364篇 |
2014年 | 28768篇 |
2013年 | 87877篇 |
2012年 | 36169篇 |
2011年 | 48456篇 |
2010年 | 42201篇 |
2009年 | 50360篇 |
2008年 | 45359篇 |
2007年 | 42593篇 |
2006年 | 45610篇 |
2005年 | 39883篇 |
2004年 | 42442篇 |
2003年 | 42288篇 |
2002年 | 41341篇 |
2001年 | 38375篇 |
2000年 | 36639篇 |
1999年 | 35618篇 |
1998年 | 46946篇 |
1997年 | 40587篇 |
1996年 | 36345篇 |
1995年 | 31506篇 |
1994年 | 29562篇 |
1993年 | 29109篇 |
1992年 | 26536篇 |
1991年 | 23628篇 |
1990年 | 23873篇 |
1989年 | 22950篇 |
1988年 | 21448篇 |
1987年 | 19723篇 |
1986年 | 19188篇 |
1985年 | 22573篇 |
1984年 | 22691篇 |
1983年 | 20571篇 |
1982年 | 19425篇 |
1981年 | 19492篇 |
1980年 | 18096篇 |
1979年 | 18743篇 |
1978年 | 17922篇 |
1977年 | 17987篇 |
1976年 | 19538篇 |
1975年 | 16110篇 |
1974年 | 15646篇 |
1973年 | 15719篇 |
1972年 | 13209篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
291.
Senthilkumar M. Vasundhara M. G. Kalavathi G. K. 《International Journal of Mechanics and Materials in Design》2019,15(3):611-627
International Journal of Mechanics and Materials in Design - The resonant frequency of electromechanical energy harvester should be tuned to ambient frequency so as to maximize the harvester power.... 相似文献
292.
Radiochemistry - Azathioprine, an antitumor agent, was labeled with 99mTc using stannous chloride dihydrate as a reducing agent. Factors such as the amounts of the reducing agent and substrate, pH,... 相似文献
293.
294.
A novel dual-rotation bobbin tool friction stir welding (DBT-FSW) was developed, in which the upper shoulder (US) and lower shoulder (LS) have different rotational speeds. This process was tried to weld 3.2 mm thick aluminum-lithium alloy sheets. The metallographic analysis and torque measurement were carried out to characterize the weld formability. Experimental results show that compared to conventional bobbin tool friction stir welding, the DBT-FSW has an excellent process stability, and can produce the defect-free joints in a wider range of welding parameters. These can be attributed to the significant improvement of material flow caused by the formation of a staggered layer structure and the unbalanced force between the US and LS during the DBT-FSW process. 相似文献
295.
The patent literature concerning thermal spraying for biomedical applications is reviewed in this contribution. The patents were compiled from multiple databases search spanning the 2005-2018 period. For clarity and ease of reading, the results have been grouped into sections according to four individual material groups (apatites, titanium, oxide ceramics, other), with the secondary sorting criterion being related to the specific bioapplication areas (maxillofacial, orthopedic, methods). Lastly, the patents are grouped according to the selected thermal spray method within the individual subsections. In the paper, recent R&D trends in this field are further identified and briefly commented. 相似文献
296.
ABSTRACTIn recent times, the applications of multimedia are rising in a greedy mode and hence the amount of video transactions is also increasing exponentially. This has shouted great demands on effective models on video encoding and also for reducing the transmission channel congestion. This research work introduces a managing technique termed weighted encoding for High-Efficiency Video Coding (HEVC). HEVC, also termed as MPEG-H Part 2 and H.265 is a video compression standard that is widely utilized AVC (H.264 or MPEG-4 Part 10). When compared to AVC, HEVC grants double the ratio of data compression at a similar level of quality of the video or considerably enhanced video quality at a similar bit rate. This work intends to optimize the weight that adopted in HEVC for encoding. For this, this paper proposes a new Iterative based propagation update in the water wave Optimization Algorithm (IPU-WWO), which is the improved form of Water wave Optimization (WWO). The performance of proposed IPU-WWO is compared over other conventional methods like Artificial Bee Colony (ABC), Firefly (FF), Particle Swarm Optimization (PSO) and Genetic Algorithm (GA) with respect to Peak Signal to Noise Ratio (PSNR). By doing the encoding process, it minimizes the video size with perceptually better quality video or PSNR. 相似文献
297.
298.
299.
300.
Alfredo M. Gravagnuolo Eden Morales‐Narváez Charlene Regina Santos Matos Sara Longobardi Paola Giardina Arben Merkoçi 《Advanced functional materials》2015,25(38):6084-6092
Class I hydrophobin Vmh2, a peculiar surface active and versatile fungal protein, is known to self‐assemble into chemically stable amphiphilic films, to be able to change wettability of surfaces, and to strongly adsorb other proteins. Herein, a fast, highly homogeneous and efficient glass functionalization by spontaneous self‐assembling of Vmh2 at liquid–solid interfaces is achieved (in 2 min). The Vmh2‐coated glass slides are proven to immobilize not only proteins but also nanomaterials such as graphene oxide (GO) and quantum dots (QDs). As models, bovine serum albumin labeled with Alexa 555 fluorophore, anti‐immunoglobulin G antibodies, and cadmium telluride QDs are patterned in a microarray fashion in order to demonstrate functionality, reproducibility, and versatility of the proposed substrate. Additionally, a GO layer is effectively and homogeneously self‐assembled onto the studied functionalized surface. This approach offers a quick and simple alternative to immobilize nanomaterials and proteins, which is appealing for new bioanalytical and nanobioenabled applications. 相似文献