全文获取类型
收费全文 | 1839篇 |
免费 | 35篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 5篇 |
化学工业 | 213篇 |
金属工艺 | 70篇 |
机械仪表 | 18篇 |
建筑科学 | 29篇 |
矿业工程 | 1篇 |
能源动力 | 42篇 |
轻工业 | 84篇 |
水利工程 | 2篇 |
石油天然气 | 4篇 |
无线电 | 75篇 |
一般工业技术 | 161篇 |
冶金工业 | 1096篇 |
原子能技术 | 14篇 |
自动化技术 | 61篇 |
出版年
2023年 | 5篇 |
2021年 | 10篇 |
2020年 | 13篇 |
2019年 | 14篇 |
2018年 | 16篇 |
2017年 | 16篇 |
2016年 | 28篇 |
2015年 | 8篇 |
2014年 | 20篇 |
2013年 | 44篇 |
2012年 | 39篇 |
2011年 | 52篇 |
2010年 | 32篇 |
2009年 | 33篇 |
2008年 | 48篇 |
2007年 | 29篇 |
2006年 | 21篇 |
2005年 | 17篇 |
2004年 | 32篇 |
2003年 | 20篇 |
2002年 | 20篇 |
2001年 | 18篇 |
2000年 | 21篇 |
1999年 | 47篇 |
1998年 | 324篇 |
1997年 | 188篇 |
1996年 | 126篇 |
1995年 | 84篇 |
1994年 | 62篇 |
1993年 | 64篇 |
1992年 | 14篇 |
1991年 | 18篇 |
1990年 | 17篇 |
1989年 | 19篇 |
1988年 | 20篇 |
1987年 | 19篇 |
1986年 | 21篇 |
1985年 | 29篇 |
1984年 | 6篇 |
1983年 | 9篇 |
1982年 | 18篇 |
1981年 | 13篇 |
1980年 | 14篇 |
1979年 | 13篇 |
1978年 | 9篇 |
1977年 | 32篇 |
1976年 | 103篇 |
1973年 | 6篇 |
1971年 | 6篇 |
1967年 | 10篇 |
排序方式: 共有1875条查询结果,搜索用时 15 毫秒
1.
Dr. Vlastimil Jirasko Dr. Nils-Alexander Lakomek Dr. Susanne Penzel Dr. Marie-Laure Fogeron Prof. Dr. Ralf Bartenschlager Prof. Dr. Beat H. Meier Dr. Anja Böckmann 《Chembiochem : a European journal of chemical biology》2020,21(10):1453-1460
Proton-detected 100 kHz magic-angle-spinning (MAS) solid-state NMR is an emerging analysis method for proteins with only hundreds of microgram quantities, and thus allows structural investigation of eukaryotic membrane proteins. This is the case for the cell-free synthesized hepatitis C virus (HCV) nonstructural membrane protein 4B (NS4B). We demonstrate NS4B sample optimization using fast reconstitution schemes that enable lipid-environment screening directly by NMR. 2D spectra and relaxation properties guide the choice of the best sample preparation to record 2D 1H-detected 1H,15N and 3D 1H,13C,15N correlation experiments with linewidths and sensitivity suitable to initiate sequential assignments. Amino-acid-selectively labeled NS4B can be readily obtained using cell-free synthesis, opening the door to combinatorial labeling approaches which should enable structural studies. 相似文献
2.
Design of 5.9 ghz dsrc-based vehicular safety communication 总被引:3,自引:0,他引:3
Daniel Jiang Vikas Taliwal Andreas Meier Wieland Holfelder Ralf Herrtwich 《Wireless Communications, IEEE》2006,13(5):36-43
The automotive industry is moving aggressively in the direction of advanced active safety. Dedicated short-range communication (DSRC) is a key enabling technology for the next generation of communication-based safety applications. One aspect of vehicular safety communication is the routine broadcast of messages among all equipped vehicles. Therefore, channel congestion control and broadcast performance improvement are of particular concern and need to be addressed in the overall protocol design. Furthermore, the explicit multichannel nature of DSRC necessitates a concurrent multichannel operational scheme for safety and non-safety applications. This article provides an overview of DSRC based vehicular safety communications and proposes a coherent set of protocols to address these requirements 相似文献
3.
GN Mozhokina GB Sokolova OV Makarova LP Mikha?lova 《Canadian Metallurgical Quarterly》1996,41(7-8):31-33
The effect of lomefloxacin was studied on mice with experimental infection due to Mycobacterium tuberculosis. The antibiotic was administered in doses of 100 and 200 mg/kg. It was shown that the use of lomefloxacin for a month provided a lower death rate of the animals with progressing acute generalized tuberculosis, a lower level of the lesions in the internal organs and a lower number of the Mycobacterium isolates from them. The efficacy of the treatment depended on the drug dose. When lomefloxacin was used in a dose of 200 mg/kg, the survival rate was much higher and the number of the epithelial unicellular granulomas in the tissue of the lung and spleen was markedly decreased while with the lower dose the indices did not differ from those in the control. 相似文献
4.
Cypriano G da Trindade Neto Ana LP Fernandes Ana IB Santos Waldenice A Morais Marcos VM Navarro Tereza NC Dantas Mrcia R Pereira Jos LC Fonseca 《Polymer International》2005,54(4):659-666
Complexation of chitosan in aqueous solutions by low molecular weight electrolytes is one of the simplest methods for the preparation of aqueous chitosan dispersions. In this work, the influence of storage time, sulfate concentration, method of preparation and surfactant content on some properties of the resultant chitosan dispersions (turbidity, viscosity and zeta potential) was analyzed. Turbidimetry was adequate to monitor the formation of particles, while viscometry was suitable to monitor changes in the dispersing phase. An analysis of the properties of these systems, mainly in terms of particle–particle and macromolecule–macromolecule interactions was carried out. Copyright © 2004 Society of Chemical Industry 相似文献
5.
Anastasiya Rybak Patrice A. Fokou Michael A. R. Meier 《European Journal of Lipid Science and Technology》2008,110(9):797-804
Olefin metathesis, awarded with the Nobel Prize in Chemistry 2005 for Chauvin, Grubbs and Schrock, has emerged as a powerful tool for organic as well as polymer chemistry. In oleochemistry, this reaction is well known and has been applied for many decades. Examples include the functionalization of the double bonds of different oleochemicals or the (direct) polymerization of plant oils via metathesis. More recent developments, particularly the development of better and more robust catalysts, allow for highly efficient cross‐metathesis reactions opening new possibilities for the direct introduction of chemical functionalities. Within this contribution, the development of metathesis in oleochemistry will be discussed, covering self‐metathesis as well as more recent developments in the field of cross‐metathesis that lead to desired platform chemicals. 相似文献
6.
7.
8.
9.
10.
From 1986 through to 1990 a total of 483 in situ bypass procedures were performed in 444 patients. Preoperative risk-factors were equally distributed among diabetic (DM) and non-diabetic (NDM) patients, except for smoking habits (DM:48%, NDM:64%, p = 0.002) and cardiac disease (DM:45%, NDM:29%, p = 0.005). Critical limb-ischaemia was more often present in diabetic than non-diabetic patients (DM:57%, NDM:36%, p = 0.0002). Diabetic patients had a significantly lower distal anastomosis than non-diabetic patients (p = 0.00001). There were no differences among diabetic and non-diabetic patients regarding three years primary and secondary patency (58% and 64% respectively), and regarding major amputations. However, the rate of minor amputations was higher in insulin-dependent compared with non-insulin-dependent diabetics, who in turn had a higher rate than non-diabetics (p < 0.00001). A markedly decreased survival rate was found in diabetics (p < 0.00005). We found the in situ bypass technique very useful in the treatment of critical ischaemia of the lower limb in diabetic patients. The overall results in diabetic patients, whether insulin-dependent or not, were equal to those in non-diabetic patients. 相似文献