全文获取类型
收费全文 | 1510篇 |
免费 | 2篇 |
专业分类
电工技术 | 1篇 |
化学工业 | 7篇 |
机械仪表 | 1篇 |
建筑科学 | 2篇 |
轻工业 | 17篇 |
无线电 | 1篇 |
一般工业技术 | 6篇 |
冶金工业 | 1469篇 |
原子能技术 | 2篇 |
自动化技术 | 6篇 |
出版年
2022年 | 1篇 |
2018年 | 2篇 |
2017年 | 1篇 |
2015年 | 1篇 |
2013年 | 1篇 |
2012年 | 1篇 |
2011年 | 3篇 |
2010年 | 3篇 |
2009年 | 4篇 |
2008年 | 7篇 |
2007年 | 6篇 |
2006年 | 1篇 |
2005年 | 7篇 |
2004年 | 10篇 |
2003年 | 7篇 |
2002年 | 3篇 |
2001年 | 4篇 |
1999年 | 32篇 |
1998年 | 385篇 |
1997年 | 248篇 |
1996年 | 156篇 |
1995年 | 87篇 |
1994年 | 80篇 |
1993年 | 75篇 |
1992年 | 12篇 |
1991年 | 34篇 |
1990年 | 28篇 |
1989年 | 30篇 |
1988年 | 36篇 |
1987年 | 34篇 |
1986年 | 18篇 |
1985年 | 18篇 |
1983年 | 2篇 |
1982年 | 7篇 |
1981年 | 7篇 |
1980年 | 16篇 |
1978年 | 5篇 |
1977年 | 43篇 |
1976年 | 90篇 |
1975年 | 4篇 |
1968年 | 1篇 |
1962年 | 1篇 |
1955年 | 1篇 |
排序方式: 共有1512条查询结果,搜索用时 0 毫秒
51.
MK Hong SW Park CW Lee DH Kang JK Song JJ Kim SJ Park MK Hong GS Mintz MB Leon 《Canadian Metallurgical Quarterly》1998,82(5):670-3, A8
We evaluated the role of intravascular ultrasound (IVUS) in 16 patients with unprotected left main coronary artery (LMCA) stenting compared with 80 patients with other (non-LMCA) native coronary artery stenting and found that (1) additional high-pressure or larger size balloon dilations were more frequently performed in LMCA stenting than in non-LMCA stenting (p <0.05) and (2) after IVUS-guided stent implantation, minimum lumen area was > or = 9 mm2 in 88% of patients who underwent LMCA stenting and in 19% of those who underwent non-LMCA stenting (p <0.001). IVUS guidance may be a more important adjunctive imaging modality in the stenting of unprotected LMCA stenoses than in stenting of non-LMCA stenoses. 相似文献
52.
TA Millward CW Heizmann BW Sch?fer BA Hemmings 《Canadian Metallurgical Quarterly》1998,17(20):5913-5922
Ndr is a nuclear serine/threonine protein kinase that belongs to a subfamily of kinases identified as being critical for the regulation of cell division and cell morphology. The regulatory mechanisms that control Ndr activity have not been characterized previously. In this paper, we present evidence that Ndr is regulated by EF-hand calcium-binding proteins of the S100 family, in response to changes in the intracellular calcium concentration. In vitro, S100B binds directly to and activates Ndr in a Ca2+-dependent manner. Moreover, Ndr is recovered from cell lysates in anti-S100B immunoprecipitates. The region of Ndr responsible for interaction with Ca2+/S100B is a basic/hydrophobic motif within the N-terminal regulatory domain of Ndr, and activation of Ndr by Ca2+/S100B is inhibited by a synthetic peptide derived from this region. In cultured cells, Ndr is rapidly activated following treatment with Ca2+ ionophore, and this activation is dependent upon the identified Ca2+/S100B-binding domain. Finally, Ndr activity is inhibited by W-7 in melanoma cells overexpressing S100B, but is unaffected by W-7 in melanoma cells that lack S100B. These results suggest that Ndr is regulated at least in part by changes in the intracellular calcium concentration, through binding of S100 proteins to its N-terminal regulatory domain. 相似文献
53.
54.
RK Nakamoto S Verjovski-Almeida KE Allen A Ambesi R Rao CW Slayman 《Canadian Metallurgical Quarterly》1998,273(13):7338-7344
There is strong evidence that Asp-378 of the yeast PMA1 ATPase plays an essential role in ATP hydrolysis by forming a covalent beta-aspartyl phosphate reaction intermediate. In this study, Asp-378 was replaced by Asn, Ser, and Glu, and the mutant ATPases were expressed in a temperature-sensitive secretion-deficient strain (sec6-4) that allowed their properties to be examined. Although all three mutant proteins were produced at nearly normal levels and remained stable for at least 2 h at 37 degrees C, they failed to travel to the vesicles that serve as immediate precursors of the plasma membrane; instead, they became arrested at an earlier step of the secretory pathway. A closer look at the mutant proteins revealed that they were firmly inserted into the bilayer and were not released by washing with high salt, urea, or sodium carbonate (pH 11), treatments commonly used to strip nonintegral proteins from membranes. However, all three mutant ATPases were extremely sensitive to digestion by trypsin, pointing to a marked abnormality in protein folding. Furthermore, in contrast to the wild-type enzyme, the mutant ATPases could not be protected against trypsinolysis by ligands such as MgATP, MgADP, or inorganic orthovanadate. Thus, Asp-378 functions in an unexpectedly complex way during the acquisition of a mature structure by the yeast PMA1 ATPase. 相似文献
55.
56.
57.
58.
59.
60.