全文获取类型
收费全文 | 613篇 |
免费 | 4篇 |
国内免费 | 1篇 |
专业分类
化学工业 | 9篇 |
金属工艺 | 1篇 |
矿业工程 | 1篇 |
能源动力 | 1篇 |
轻工业 | 5篇 |
无线电 | 9篇 |
一般工业技术 | 8篇 |
冶金工业 | 579篇 |
自动化技术 | 5篇 |
出版年
2022年 | 1篇 |
2021年 | 1篇 |
2018年 | 1篇 |
2017年 | 2篇 |
2016年 | 2篇 |
2015年 | 1篇 |
2013年 | 4篇 |
2012年 | 1篇 |
2011年 | 2篇 |
2010年 | 4篇 |
2006年 | 5篇 |
2004年 | 1篇 |
2003年 | 2篇 |
2002年 | 2篇 |
2001年 | 2篇 |
1999年 | 22篇 |
1998年 | 173篇 |
1997年 | 91篇 |
1996年 | 70篇 |
1995年 | 41篇 |
1994年 | 29篇 |
1993年 | 28篇 |
1992年 | 5篇 |
1991年 | 16篇 |
1990年 | 20篇 |
1989年 | 18篇 |
1988年 | 16篇 |
1987年 | 9篇 |
1986年 | 9篇 |
1985年 | 16篇 |
1982年 | 3篇 |
1981年 | 1篇 |
1980年 | 4篇 |
1977年 | 3篇 |
1976年 | 13篇 |
排序方式: 共有618条查询结果,搜索用时 0 毫秒
41.
J Bandorowicz-Piku?a A Wrzosek S Piku?a YC Awasthi 《Canadian Metallurgical Quarterly》1997,248(1):238-244
Annexin VI is a 68-kDa calcium-, phospholipid-, and cytoskeletal-element-binding protein, which has been implicated in various processes, including calcium release and sequestration in calcifying cartilage, in a receptor-mediated endocytosis in human fibroblasts, and in secretion from chromaffin granules. In these processes it was found that, in addition to Ca2+ and annexin, the presence of ATP is also a prerequisite. In the present report we show that annexin VI binds ATP and the binding of nucleotide to protein is accompanied by quenching of an intrinsic fluorescence of annexin VI, which was found to be specific for 2'-(or 3')-O-(2,4,6-trinitrophenyl)adenosine 5'-triphosphate, GTP and ATP, and dependent on the annexin conformation. The nucleotide-binding site within an annexin VI molecule is likely to be close to the tryptophan-containing domain of annexin VI. We propose that ATP plays the role of a physiological ligand for annexin VI, and its binding to annexin VI may represent an alternative cellular mechanism for the regulation of annexin-membrane interactions coupled to overall energy transitions in the cell. 相似文献
42.
The characteristics of TCP and UDP lead to different network transmission behaviours. TCP is responsive to network congestion whereas UDP is not. This paper proposes two mechanisms that operate at the source node to regulate TCP and UDP flows and provide a differential service for them. One is the congestion‐control mechanism, which uses congestion signal detected by TCP flows to regulate the flows at the source node. Another is the time‐slot mechanism, which assigns different number of time slots to flows to control their flow transmission. Based on the priority of each flow, different bandwidth proportions are allocated for each flow and differential services are provided. Simulation results show some insights of these two mechanisms. Moreover, we summarize the factors that may impact the performance of these two mechanisms. Copyright © 2001 John Wiley & Sons, Ltd. 相似文献
43.
44.
45.
46.
47.
An actin-depolymerizing marine natural product, mycalolide B, and a related compound, kabiramide D, were labeled with biocytin, a biotin derivative, and used to specify target molecules in cultured rat 3Y1 fibroblasts. Mycalolide B exhibited the ability to bind to various intracellular proteins, probably through the Michael addition of a sulfhydryl group to C5 of mycalolide B. However, no intracellular proteins other than actin apparently reacted with biocytinylated kabiramide D, demonstrating that the binding of kabiramide D to actin was highly specific. Cells treated with biocytinylated kabiramide D followed by staining with fluorescein isothiocyanate-conjugated avidin showed that biocytinylated kabiramide D bound to stress fibers composed of F-actin, although the staining intensity was weaker than the fluorescent phalloidin staining. The assay for the binding of kabiramide D to actin, which had previously been treated with other actin-depolymerizing agents, showed that the actin-binding site for kabiramide D was the same as that for bistheonellide A, but not those for latrunculin A and cytochalasin D. 相似文献
48.
TF Davenport JR Albright JH Goldman SL Hagopian JE Lannutti KW Lai J LeBritton YC Lin AE Pifer HC Fenker DR Green GE Canough CC Chang TC Davis RW Joyner JA Poirier CH Georgiopoulos A Napier JM Marraffino JW Waters MS Webster EG Williams J Woosley JR Ficenec S Torres WP Trower 《Canadian Metallurgical Quarterly》1986,33(9):2519-2527
49.
50.
The purpose of this study was to investigate sexual knowledge, attitudes and behavior of fifth and sixth grade students in aboriginal elementary schools in the Ping-Tung area. A structured questionnaire was administered to 1091 students who were selected by cluster sampling. The results showed: (1) The sexual knowledge score was low but sexual attitudes showed a positive trend. (2) 64.7% and 67.4% of students had at some time seen pictures of male or female sexual organs. (3) About 61% of students had seen sexual magazines or videotapes. (4) 66.2% of male and 88.1% of female students had heard about wet dreams or menstruation before their first experience; more than half of the students thought that wet dreams need treatment. (5) 17.8% of students had masturbation experience, and after that 59.3% of students had fear or guilt feeling. (6) Female students had significantly higher knowledge and attitude scores than male students, Demographic variables produced no significant difference in the above scores. (7) 42.4% of students most desired to know what phenomena indicate sexual maturity. (8) Sex knowledge had significantly positive correlation with sex attitude. 相似文献