全文获取类型
收费全文 | 50089篇 |
免费 | 4622篇 |
国内免费 | 1776篇 |
专业分类
电工技术 | 2321篇 |
技术理论 | 1篇 |
综合类 | 2256篇 |
化学工业 | 9091篇 |
金属工艺 | 2725篇 |
机械仪表 | 3198篇 |
建筑科学 | 2642篇 |
矿业工程 | 914篇 |
能源动力 | 1683篇 |
轻工业 | 3935篇 |
水利工程 | 734篇 |
石油天然气 | 1329篇 |
武器工业 | 302篇 |
无线电 | 7383篇 |
一般工业技术 | 7836篇 |
冶金工业 | 2709篇 |
原子能技术 | 675篇 |
自动化技术 | 6753篇 |
出版年
2024年 | 221篇 |
2023年 | 827篇 |
2022年 | 1484篇 |
2021年 | 2271篇 |
2020年 | 1598篇 |
2019年 | 1359篇 |
2018年 | 1703篇 |
2017年 | 1796篇 |
2016年 | 1737篇 |
2015年 | 1895篇 |
2014年 | 2710篇 |
2013年 | 3329篇 |
2012年 | 3549篇 |
2011年 | 3977篇 |
2010年 | 3177篇 |
2009年 | 3042篇 |
2008年 | 2961篇 |
2007年 | 2593篇 |
2006年 | 2320篇 |
2005年 | 1866篇 |
2004年 | 1512篇 |
2003年 | 1425篇 |
2002年 | 1482篇 |
2001年 | 1268篇 |
2000年 | 954篇 |
1999年 | 833篇 |
1998年 | 1018篇 |
1997年 | 659篇 |
1996年 | 610篇 |
1995年 | 437篇 |
1994年 | 331篇 |
1993年 | 272篇 |
1992年 | 189篇 |
1991年 | 168篇 |
1990年 | 121篇 |
1989年 | 118篇 |
1988年 | 96篇 |
1987年 | 91篇 |
1986年 | 74篇 |
1985年 | 58篇 |
1984年 | 47篇 |
1983年 | 39篇 |
1982年 | 37篇 |
1981年 | 32篇 |
1980年 | 43篇 |
1979年 | 19篇 |
1977年 | 23篇 |
1976年 | 34篇 |
1975年 | 18篇 |
1974年 | 16篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
31.
32.
Manjunatha S. Muttigi Byoung Ju Kim Bogyu Choi Inbo Han Hansoo Park Soo-Hong Lee 《International journal of molecular sciences》2020,21(23)
Adipose-derived mesenchymal stromal cells (Ad-MSCs) are a promising tool for articular cartilage repair and regeneration. However, the terminal hypertrophic differentiation of Ad-MSC-derived cartilage is a critical barrier during hyaline cartilage regeneration. In this study, we investigated the role of matrilin-3 in preventing Ad-MSC-derived chondrocyte hypertrophy in vitro and in an osteoarthritis (OA) destabilization of the medial meniscus (DMM) model. Methacrylated hyaluron (MAHA) (1%) was used to encapsulate and make scaffolds containing Ad-MSCs and matrilin-3. Subsequently, the encapsulated cells in the scaffolds were differentiated in chondrogenic medium (TGF-β, 1–14 days) and thyroid hormone hypertrophic medium (T3, 15–28 days). The presence of matrilin-3 with Ad-MSCs in the MAHA scaffold significantly increased the chondrogenic marker and decreased the hypertrophy marker mRNA and protein expression. Furthermore, matrilin-3 significantly modified the expression of TGF-β2, BMP-2, and BMP-4. Next, we prepared the OA model and transplanted Ad-MSCs primed with matrilin-3, either as a single-cell suspension or in spheroid form. Safranin-O staining and the OA score suggested that the regenerated cartilage morphology in the matrilin-3-primed Ad-MSC spheroids was similar to the positive control. Furthermore, matrilin-3-primed Ad-MSC spheroids prevented subchondral bone sclerosis in the mouse model. Here, we show that matrilin-3 plays a major role in modulating Ad-MSCs’ therapeutic effect on cartilage regeneration and hypertrophy suppression. 相似文献
33.
Multifunctional 3D Patternable Drug‐Embedded Nanocarrier‐Based Interfaces to Enhance Signal Recording and Reduce Neuron Degeneration in Neural Implantation
下载免费PDF全文
![点击此处可从《Advanced materials (Deerfield Beach, Fla.)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
34.
Microsystem Technologies - Since traction motors for electric vehicles require a variety of features to be used simultaneously, research on the design optimization of permanent magnet synchronous... 相似文献
35.
Journal of Computer Science and Technology - New non-volatile memory (NVM) technologies are expected to replace main memory DRAM (dynamic random access memory) in the near future. NAND flash... 相似文献
36.
Hwang Seongil Park Sang Hyun Jin Maolin Kang Sang Hoon 《Intelligent Service Robotics》2021,14(3):471-484
Intelligent Service Robotics - A robust control designed for multiple degrees-of-freedom (DOF) robot manipulators performing complex tasks requiring frequent physical interaction with unknown... 相似文献
37.
Peng Jiang Jiafeng Lu Kun Li Xiquan Chen Ruiqi Dan 《Fullerenes, Nanotubes and Carbon Nanostructures》2020,28(5):381-386
AbstractPreparation condition can affect the structure and the properties of nanofiber membrane. In order to explore suitable conditions to prepare the Fe3O4/PVDF nanofiber membrane with good hydrophobicity, the hydrophobicity of Fe3O4/PVDF nanofiber membranes obtained by electrospinning was investigated by changing preparation conditions like weight percentage of Fe3O4 nanoparticles, blending quality concentration of poly (vinylidene fluoride) (PVDF) and Fe3O4 nanoparticles, and positive voltage. And the variations of hydrophobicity of Fe3O4/PVDF nanofiber membranes modified by 1H, 1H, 2H, 2H-perfluorodecyl trimethoxysilane were studied. The results show that the hydrophobicity of Fe3O4/PVDF nanofiber membranes has changed under different preparation conditions. The contact angles of samples increased after a modification by 1H, 1H, 2H, 2H-perfluorodecyl trimethoxysilane, which indicates that the hydrophobicity of Fe3O4/PVDF nanofiber membranes has been enhanced. 相似文献
38.
39.
40.