全文获取类型
收费全文 | 340篇 |
免费 | 4篇 |
专业分类
电工技术 | 2篇 |
综合类 | 2篇 |
化学工业 | 63篇 |
金属工艺 | 9篇 |
机械仪表 | 5篇 |
建筑科学 | 15篇 |
能源动力 | 5篇 |
轻工业 | 34篇 |
无线电 | 7篇 |
一般工业技术 | 40篇 |
冶金工业 | 122篇 |
原子能技术 | 6篇 |
自动化技术 | 34篇 |
出版年
2022年 | 5篇 |
2021年 | 3篇 |
2020年 | 7篇 |
2017年 | 5篇 |
2016年 | 3篇 |
2015年 | 5篇 |
2014年 | 4篇 |
2013年 | 7篇 |
2011年 | 11篇 |
2010年 | 13篇 |
2009年 | 8篇 |
2008年 | 12篇 |
2007年 | 8篇 |
2006年 | 15篇 |
2005年 | 9篇 |
2004年 | 4篇 |
2003年 | 7篇 |
2002年 | 8篇 |
2001年 | 8篇 |
2000年 | 3篇 |
1999年 | 5篇 |
1998年 | 22篇 |
1997年 | 20篇 |
1996年 | 9篇 |
1995年 | 13篇 |
1994年 | 9篇 |
1993年 | 13篇 |
1992年 | 6篇 |
1990年 | 4篇 |
1989年 | 4篇 |
1988年 | 6篇 |
1987年 | 3篇 |
1986年 | 3篇 |
1985年 | 4篇 |
1983年 | 5篇 |
1982年 | 3篇 |
1981年 | 4篇 |
1980年 | 5篇 |
1979年 | 3篇 |
1978年 | 3篇 |
1976年 | 12篇 |
1974年 | 3篇 |
1969年 | 2篇 |
1966年 | 3篇 |
1957年 | 4篇 |
1952年 | 3篇 |
1951年 | 2篇 |
1948年 | 2篇 |
1905年 | 2篇 |
1901年 | 2篇 |
排序方式: 共有344条查询结果,搜索用时 46 毫秒
21.
F. Schulz W. Bavendamm H. Mayer-Wegelin K. Lünzmann W. Sandermann H. Witt H. Kübler E. Buchholz R. Keylwerth H. Matz 《Holz als Roh- und Werkstoff》1952,10(9):367-374
Ohne Zusammenfassung 相似文献
22.
H. H. Fickler H. Witt K. Lünzmann W. Bavendamm H. Mayer-Wegelin R. Runkel H. Witt H. Schambach H. Stockmann R. Keylwerth H. Kübler K. Rügge E. Plath H. Brüning F. Kollmann M. Lüthgens F. Schulz 《Holz als Roh- und Werkstoff》1952,10(11):440-447
Ohne Zusammenfassung 相似文献
23.
K. Rügge F. Schulz W. Bavendamm R. Runkel J. Weck H. Mayer-Wegelin R. Keylwerth H. Witt A. Kienzle 《Holz als Roh- und Werkstoff》1951,9(8):319-329
Ohne Zusammenfassung 相似文献
24.
W. Bavendamm J. Weck H. Mayer-Wegelin R. Keylwerth F. Schulz K. Egner W. Sandermann H. Witt R. Runkel F. Kollmann A. Kienzle 《Holz als Roh- und Werkstoff》1951,9(7):281-288
Ohne Zusammenfassung 相似文献
25.
Ulrich Witt 《Industry and innovation》2002,9(1-2):7-22
The generic features of an evolutionary theory which are identified in the conceptional discussion of the present paper can be shown to be present already in Schumpeter's 1912 work, The Theory of Economic Development . None the less, it is argued that Schumpeter fell short of a level of generality by which he would have succeeded in providing a true foundation for evolutionary economics. The reason is his eagerness--very clearly visible in the "lost" seventh chapter--to align his theory with the economic reasoning of contemporary "pure" economic theory that was moulded in an equilibrium-oriented heuristic and the methodology of comparative statics. Schumpeter's conception--which, in opposing the idea of borrowing from Darwinian thought, he called "development"--is rather a special theory of the unsteady capitalist growth process passing through booms and crises. Throughout all of Schumpeter's writings the notion of development is therefore closely related to the business cycle phenomenon. The paper argues that this special framing implies not only some arbitrary hypotheses which are difficult to accept in an evolutionary interpretation, but also some limitations in his understanding of (what he refused to call) economic evolution, particularly with respect to its driving forces. 相似文献
26.
Aluminium nitride ceramics containing 15-30 w/o of SiC whiskers can be sintered tofull density(by hot pressing at 1800℃)using2-3 w/o of Y_2O_3,additions.The whiskersincrease the toughness and strength of thecomposite,K_(10) increasing from 2.8 to about5.0 and flexural strength increasing by 30-50%.However,the whiskers must be welldispersed and if the dispersion is notsatisfactory,toughness may increase but thestrength decreases.The hot-pressingtemperature can be reduced by up to 100℃ ifY(NO_3)_3 .5H_20 is used as the sinteringadditive instead of Y_2O_3,but some oxidation ofthe AIN occurs during heating.Isopropan-2-01 is a better dispersing agent thancyclohexane,but again some oxidation of theAIN does occur.The best sample prepared during this work contained 20 w/o of SiC whiskers and 2 w/oY_2O_3 added as Y(NO_3)_3. 5H_2O and mixed inisopropanol.This exhibited a mean strength of453MPa(maximum 522MPa,measured bydisc flexure)and a fracture toughness of5.5MPam~(1/2). 相似文献
27.
Interleukin-8, a member of the CXC chemokine family, has been shown to bind to glycosaminoglycans. It has been suggested that heparan sulfate on cell surfaces could provide specific ligand sites on endothelial cells to retain the highly diffusible inflammatory chemokine for presentation to leukocytes. By using selectively modified heparin and heparan sulfate fragments in a nitrocellulose filter trapping system, we have analyzed sequence requirements for interleukin-8 binding to heparin/heparan sulfate. We demonstrate that the affinity of a monomeric interleukin-8 molecule for heparin/heparan sulfate is too weak to allow binding at physiological ionic strength, whereas the dimeric form of the protein mediates binding to two sulfated domains of heparan sulfate. These domains, each an N-sulfated block of approximately 6 monosaccharide units, are contained within an approximately 22-24-mer sequence and are separated by a region of =14 monosaccharide residues that may be fully N-acetylated. Binding to interleukin-8 correlates with the occurrence of the di-O-sulfated disaccharide unit -IdceA(2-OSO3)-GlcNSO3(6-OSO3)-. We suggest that the heparan sulfate sequence binds in horseshoe fashion over two antiparallel-oriented helical regions on the dimeric protein. 相似文献
28.
29.
30.
Thin film aluminium oxide capacitors using anodic Al2O3 as the dielectric are described. The dependence of oxide thickness and dielectric loss on anodization voltage was studied. Variation of capacitance with temperature and frequency was also investigated. The capacitors were used in conjunction with tantalum resistors to fabricate an astable multivibrator circuit and the waveforms were recorded. The combination of aluminium oxide capacitors and tantalum resistors has some advantages over all-tantalum RC networks. 相似文献