全文获取类型
收费全文 | 1425篇 |
免费 | 12篇 |
专业分类
电工技术 | 22篇 |
综合类 | 1篇 |
化学工业 | 135篇 |
金属工艺 | 5篇 |
机械仪表 | 18篇 |
建筑科学 | 37篇 |
矿业工程 | 2篇 |
能源动力 | 16篇 |
轻工业 | 95篇 |
水利工程 | 8篇 |
石油天然气 | 8篇 |
无线电 | 89篇 |
一般工业技术 | 113篇 |
冶金工业 | 778篇 |
原子能技术 | 5篇 |
自动化技术 | 105篇 |
出版年
2022年 | 6篇 |
2021年 | 8篇 |
2019年 | 7篇 |
2018年 | 8篇 |
2017年 | 8篇 |
2016年 | 8篇 |
2014年 | 13篇 |
2013年 | 41篇 |
2012年 | 17篇 |
2011年 | 23篇 |
2010年 | 24篇 |
2009年 | 15篇 |
2008年 | 31篇 |
2007年 | 35篇 |
2006年 | 34篇 |
2005年 | 20篇 |
2004年 | 23篇 |
2003年 | 18篇 |
2002年 | 17篇 |
2001年 | 17篇 |
2000年 | 20篇 |
1999年 | 37篇 |
1998年 | 249篇 |
1997年 | 135篇 |
1996年 | 116篇 |
1995年 | 49篇 |
1994年 | 61篇 |
1993年 | 53篇 |
1992年 | 16篇 |
1991年 | 14篇 |
1990年 | 19篇 |
1989年 | 13篇 |
1988年 | 20篇 |
1987年 | 10篇 |
1986年 | 11篇 |
1985年 | 12篇 |
1983年 | 7篇 |
1982年 | 7篇 |
1981年 | 17篇 |
1980年 | 13篇 |
1979年 | 9篇 |
1978年 | 10篇 |
1977年 | 28篇 |
1976年 | 46篇 |
1975年 | 6篇 |
1974年 | 8篇 |
1973年 | 11篇 |
1967年 | 7篇 |
1966年 | 6篇 |
1965年 | 8篇 |
排序方式: 共有1437条查询结果,搜索用时 15 毫秒
1.
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
2.
3.
MD Goldberg JR Canvin P Freestone C Andersen D Laoudj PH Williams IB Holland V Norris 《Canadian Metallurgical Quarterly》1997,79(6):315-322
In the bacterium Escherichia coli, H-NS-(H1, H1a) is a heat-stable protein with a molecular mass of 15.5 kDa involved in nucleoid organisation and gene regulation linked to certain signal transduction pathways. We have shown that, following addition of preparations of everted inner membrane vesicles, heat-stable cleavage products of approximately 10 kDa of H-NS are formed in vitro from newly synthesised, radio-labelled H-NS and from purified H-NS. The 15.5 kDa protein and its cleavage products were also recovered from a minicell system. These results raised the possibility that cleavage of H-NS is physiologically significant. However, the cleavage of H-NS observed appears to occur during cell breakage and to depend on the method of protein extraction and the presence of the outer membrane protease, OmpT. Nevertheless, the results indicate that H-NS may contain at least two separate domains with cleavage occurring between these domains at a preferred OmpT site. Failure to take account of H-NS cleavage in sample preparation and analysis can lead to serious underestimation of H-NS levels. 相似文献
4.
The occurrence of fungi was investigated in the gut of 200 common garden lizards (Agama agama). The most important pathogenic fungus isolated was Basidiobolus haptosporus, an aetiological agent of subcutaneous zygomycosis. It was recovered from the intestinal contents of 112 (56%) lizards. Other important fungi isolated included Aspergillus spp. in 24 (12%) lizards, Candida spp. in 12 (6%), Penicillium spp. in 12 (6%) and Fusarium spp. in 12 (6%). Mucor spp. were isolated from eight (4%) male lizards only. Agamid lizards are plentiful in rural and urban areas of Nigeria. As they live in close vicinity to man, they are likely to play an important role in the spread of disease that may be caused by these fungi and its transmission to man. None of the animals investigated that yielded fungal cultures revealed any external fungal infection. 相似文献
5.
N Black 《Canadian Metallurgical Quarterly》1997,349(9068):1834-1836
6.
7.
8.
9.
J Hellman EM Zanzot PM Loiselle SF Amato KM Black Y Ge JT Kurnick HS Warren 《Canadian Metallurgical Quarterly》1997,176(5):1260-1268
The binding of IgG in antiserum to Escherichia coli J5 to the surface of Enterobacteriaceae and to cell wall fragments released from serum-exposed bacteria was studied in a search for potentially protective epitopes other than lipopolysaccharide (LPS). IgG titers to multiple heterologous gram-negative smooth bacteria increased following incubation of the bacteria in serum and decreased following absorption with serum-exposed heterologous bacteria. IgG eluted from absorbing bacteria bound to at least three conserved bacterial outer membrane proteins (OMPs), but not LPS, as assessed by immunoblotting. The same OMPs were present in LPS-containing macromolecular cell wall fragments released by incubation of heterologous gram-negative bacteria in human serum. Part of the protection offered by J5 antiserum could be from binding of IgG to conserved OMPs at the bacterial surface or to OMPs in cell-wall fragments released from dying bacteria. 相似文献
10.