全文获取类型
收费全文 | 27004篇 |
免费 | 1618篇 |
国内免费 | 68篇 |
专业分类
电工技术 | 375篇 |
综合类 | 35篇 |
化学工业 | 6420篇 |
金属工艺 | 1055篇 |
机械仪表 | 1601篇 |
建筑科学 | 514篇 |
矿业工程 | 8篇 |
能源动力 | 1139篇 |
轻工业 | 2195篇 |
水利工程 | 100篇 |
石油天然气 | 20篇 |
武器工业 | 1篇 |
无线电 | 4509篇 |
一般工业技术 | 5688篇 |
冶金工业 | 1777篇 |
原子能技术 | 332篇 |
自动化技术 | 2921篇 |
出版年
2024年 | 24篇 |
2023年 | 321篇 |
2022年 | 480篇 |
2021年 | 801篇 |
2020年 | 565篇 |
2019年 | 634篇 |
2018年 | 859篇 |
2017年 | 823篇 |
2016年 | 949篇 |
2015年 | 756篇 |
2014年 | 1200篇 |
2013年 | 1708篇 |
2012年 | 1832篇 |
2011年 | 2185篇 |
2010年 | 1637篇 |
2009年 | 1666篇 |
2008年 | 1518篇 |
2007年 | 1172篇 |
2006年 | 1026篇 |
2005年 | 889篇 |
2004年 | 801篇 |
2003年 | 772篇 |
2002年 | 746篇 |
2001年 | 629篇 |
2000年 | 558篇 |
1999年 | 533篇 |
1998年 | 835篇 |
1997年 | 496篇 |
1996年 | 457篇 |
1995年 | 306篇 |
1994年 | 209篇 |
1993年 | 178篇 |
1992年 | 154篇 |
1991年 | 120篇 |
1990年 | 100篇 |
1989年 | 119篇 |
1988年 | 85篇 |
1987年 | 79篇 |
1986年 | 63篇 |
1985年 | 51篇 |
1984年 | 48篇 |
1983年 | 40篇 |
1982年 | 34篇 |
1981年 | 35篇 |
1980年 | 33篇 |
1979年 | 14篇 |
1977年 | 30篇 |
1976年 | 44篇 |
1975年 | 20篇 |
1974年 | 13篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
3.
4.
5.
In vivo Kinetic Biodistribution of Nano‐Sized Outer Membrane Vesicles Derived from Bacteria 下载免费PDF全文
Su Chul Jang Sae Rom Kim Yae Jin Yoon Kyong‐Su Park Ji Hyun Kim Jaewook Lee Oh Youn Kim Eun‐Jeong Choi Dae‐Kyum Kim Dong‐Sic Choi Yoon‐Keun Kim Jaesung Park Dolores Di Vizio Yong Song Gho 《Small (Weinheim an der Bergstrasse, Germany)》2015,11(4):456-461
Evaluation of kinetic distribution and behaviors of nanoparticles in vivo provides crucial clues into their roles in living organisms. Extracellular vesicles are evolutionary conserved nanoparticles, known to play important biological functions in intercellular, inter‐species, and inter‐kingdom communication. In this study, the first kinetic analysis of the biodistribution of outer membrane vesicles (OMVs)—bacterial extracellular vesicles—with immune‐modulatory functions is performed. OMVs, injected intraperitoneally, spread to the whole mouse body and accumulate in the liver, lung, spleen, and kidney within 3 h of administration. As an early systemic inflammation response, increased levels of TNF‐α and IL‐6 are observed in serum and bronchoalveolar lavage fluid. In addition, the number of leukocytes and platelets in the blood is decreased. OMVs and cytokine concentrations, as well as body temperature are gradually decreased 6 h after OMV injection, in concomitance with the formation of eye exudates, and of an increase in ICAM‐1 levels in the lung. Following OMV elimination, most of the inflammatory signs are reverted, 12 h post‐injection. However, leukocytes in bronchoalveolar lavage fluid are increased as a late reaction. Taken together, these results suggest that OMVs are effective mediators of long distance communication in vivo. 相似文献
6.
Peer-to-Peer Networking and Applications - P2P-TV is a TV system that receives content through a peer-to-peer network. Content is stored in the distributed manner then to be serviced to users, and... 相似文献
7.
8.
9.
The aim of this study was to evaluate the use of total coliforms (TC) and faecal coliforms (FC) using a membrane filtration method for precise monitoring of faecal pollution in Korean surface water. The samples were collected in Korea from both main rivers and their tributaries. Presumptive TC * FC were enumerated. The ratios of presumptive FC to TC were not constant, but varied widely, and TC were difficult to enumerate because of overgrowth by background colonies. For FC this was not the case. Seven hundred and three purified strains of presumptive TC * FC and their background colonies were biotyped using API 20E. Among 272 presumptive TC, non-faecal related species, Aeromonas hydrophila dominated (34.6%) and E. coli accounted for only 5.1%. In contrast, E. coli made up 89% of the 209 presumptive FC. Furthermore, of 164 background colonies on Endo Agar LES, 54.9% was A. hydrophila, while background colonies on m-FC Agar were few (58 strains), and despite their atypical colony appearance, most of them were biotyped as enteric bacteria. These results reveal that the detection of FC rather than TC using m-FC Agar is more appropriate for faecal pollution monitoring in eutrophicated surface water located in a temperate region. 相似文献
10.
Chel-Jong Choi Tae-Yeon Seong Key-Min Lee Joo-Hyoung Lee Young-Jin Park Hi-Deok Lee 《Electron Device Letters, IEEE》2002,23(4):188-190
The leakage mechanism in p+/n shallow junctions fabricated using Co silicidation and shallow trench isolation processes has been investigated using transmission electron microscopy (TEM) combined with selective chemical etching. TEM and TSUPREM-4 simulation results show that dopant profiles bend upward near the edge of the active region. The formation of the abnormal profile is attributed to transient enhanced diffusion induced by source/drain implantation. Based on the TEM and simulation results, it is suggested that the shallower junctions formed near the active edge can serve as a source for leakage current in the silicided p+ /n shallow junctions 相似文献