全文获取类型
收费全文 | 6883篇 |
免费 | 210篇 |
国内免费 | 26篇 |
学科分类
工业技术 | 7119篇 |
出版年
2023年 | 66篇 |
2022年 | 121篇 |
2021年 | 161篇 |
2020年 | 151篇 |
2019年 | 143篇 |
2018年 | 226篇 |
2017年 | 186篇 |
2016年 | 192篇 |
2015年 | 104篇 |
2014年 | 202篇 |
2013年 | 399篇 |
2012年 | 220篇 |
2011年 | 300篇 |
2010年 | 231篇 |
2009年 | 274篇 |
2008年 | 243篇 |
2007年 | 197篇 |
2006年 | 207篇 |
2005年 | 153篇 |
2004年 | 127篇 |
2003年 | 130篇 |
2002年 | 127篇 |
2001年 | 119篇 |
2000年 | 107篇 |
1999年 | 103篇 |
1998年 | 286篇 |
1997年 | 201篇 |
1996年 | 157篇 |
1995年 | 147篇 |
1994年 | 120篇 |
1993年 | 138篇 |
1992年 | 111篇 |
1991年 | 97篇 |
1990年 | 85篇 |
1989年 | 80篇 |
1988年 | 78篇 |
1987年 | 79篇 |
1986年 | 87篇 |
1985年 | 115篇 |
1984年 | 96篇 |
1983年 | 95篇 |
1982年 | 78篇 |
1981年 | 61篇 |
1980年 | 50篇 |
1979年 | 45篇 |
1978年 | 50篇 |
1977年 | 65篇 |
1976年 | 84篇 |
1975年 | 43篇 |
1973年 | 37篇 |
排序方式: 共有7119条查询结果,搜索用时 31 毫秒
31.
Bhattacharya Subhayan Sinha Sankhamita Roy Sarbani Gupta Amarnath 《The Journal of supercomputing》2020,76(12):9882-9900
The Journal of Supercomputing - Currently, all online social networks (OSNs) are considered to follow a power-law distribution. In this paper, the degree distribution for multiple OSNs has been... 相似文献
32.
Wireless Personal Communications - The orthogonal frequency division multiplexing (OFDM) is the most encouraging multi-carrier modulation system chosen for the high data rates but the objective is... 相似文献
33.
Wireless Personal Communications - The efficient management of resource sharing plays a crucial role in the cloud execution environment. The constraints such as heterogeneity and dynamic nature of... 相似文献
34.
35.
36.
Diffusional limitations (the gel, glass, and cage effects) are manifested in several bulk free radical homopolymerizations as well as in random copolymerizations. These are associated with decreases of several orders of magnitude of the rate constants of termination, propagation, and initiation (the initiator efficiency), respectively. These phenomena have been modeled earlier using the free volume theory for the diffusivities of primary radicals, macro‐radicals, and monomer molecules, and have been applied to homopolymerizations. In this study, a similar model is developed for random bulk copolymerizations. The parameters of the model are fitted using isothermal data on styrene acrylonitrile random copolymerization carried out in small ampoules. Thereafter, best‐fit global correlations have been developed for this system. This enables the model to be used for studying non‐isothermal copolymerizations, as well as for carrying out optimization of industrial reactors, where non‐isothermal conditions are a norm. POLYM. ENG. SCI., 55:2098–2110, 2015. © 2014 Society of Plastics Engineers 相似文献
37.
Jincy Joy Jessica Pereira Rachida Aid‐Launais Graciela Pavon‐Djavid Alok R Ray Didier Letourneur Anne Meddahi‐Pell Bhuvanesh Gupta 《Polymer International》2019,68(7):1367-1377
The work reported involved the fabrication of an electrospun tubular conduit of a gelatin and polycaprolactone (PCL) blend as an adventitia‐equivalent construct. Gelatin was included as the matrix for increased biocompatibility with the addition of PCL for durability. This is contrary to most of the literature available for biomaterials based on blends of gelatin and PCL where PCL is the major matrix. The work includes the assiduous selection of key electrospinning parameters to obtain smooth bead‐free fibres with a narrow distribution of pore size and fibre diameter. Few reports elucidate the optimization of all electrospinning parameters to fabricate tubular conduits with a focus on obtaining homogeneous pores and fibres. This stepwise investigation would be unique for the fabrication of gelatin–PCL electrospun tubular constructs. The fabricated microfibrous gelatin–PCL constructs had pores of size ca 50–100 μm reportedly conducive for cell infiltration. The measured value of surface roughness of 57.99 ± 17.4 nm is reported to be favourable for protein adhesion and cell adhesion. The elastic modulus was observed to be similar to that of the tunica adventitia of the native artery. Preliminary in vitro and in vivo biocompatibility tests suggest safe applicability as a biomaterial. Minimal cytotoxicity was observed using MTT assay. Subcutaneous implantation of the scaffold demonstrated acute inflammation which decreased by day 15. The findings of this study could enable the fabrication of smooth bead‐free microfibrous gelatin–PCL tubular construct as viable biomaterial which can be included in a bilayer or a trilayer scaffold for vascular tissue engineering. © 2019 Society of Chemical Industry 相似文献
38.
Multimedia Tools and Applications - Today’s digital era has undertaken most of the responsibilities of public and private sectors, not only the industries or big organizations dependent on... 相似文献
39.
Gupta Saurabh Tolani Varun Davidson James Levine Sergey Sukthankar Rahul Malik Jitendra 《International Journal of Computer Vision》2020,128(5):1311-1330
International Journal of Computer Vision - We introduce a neural architecture for navigation in novel environments. Our proposed architecture learns to map from first-person views and plans a... 相似文献
40.
Wireless Networks - Since 1999 IEEE 802.11 has become a dominating wireless technology for providing WLAN in both public and private places. The protocol has evolved with time and the current... 相似文献