全文获取类型
收费全文 | 2865篇 |
免费 | 5篇 |
专业分类
电工技术 | 5篇 |
综合类 | 16篇 |
化学工业 | 38篇 |
金属工艺 | 3篇 |
机械仪表 | 13篇 |
建筑科学 | 16篇 |
矿业工程 | 9篇 |
能源动力 | 6篇 |
轻工业 | 9篇 |
水利工程 | 5篇 |
石油天然气 | 2篇 |
武器工业 | 2篇 |
无线电 | 3篇 |
一般工业技术 | 70篇 |
冶金工业 | 2656篇 |
原子能技术 | 2篇 |
自动化技术 | 15篇 |
出版年
2024年 | 1篇 |
2015年 | 1篇 |
2014年 | 5篇 |
2013年 | 10篇 |
2012年 | 9篇 |
2011年 | 20篇 |
2010年 | 10篇 |
2009年 | 14篇 |
2008年 | 20篇 |
2007年 | 49篇 |
2006年 | 11篇 |
2005年 | 12篇 |
2004年 | 3篇 |
2003年 | 15篇 |
2002年 | 7篇 |
2001年 | 1篇 |
2000年 | 5篇 |
1999年 | 75篇 |
1998年 | 773篇 |
1997年 | 449篇 |
1996年 | 255篇 |
1995年 | 165篇 |
1994年 | 151篇 |
1993年 | 170篇 |
1992年 | 14篇 |
1991年 | 45篇 |
1990年 | 36篇 |
1989年 | 33篇 |
1988年 | 36篇 |
1987年 | 29篇 |
1986年 | 38篇 |
1985年 | 23篇 |
1984年 | 1篇 |
1983年 | 10篇 |
1982年 | 18篇 |
1981年 | 31篇 |
1980年 | 26篇 |
1979年 | 4篇 |
1978年 | 16篇 |
1977年 | 97篇 |
1976年 | 171篇 |
1975年 | 7篇 |
1974年 | 1篇 |
1959年 | 1篇 |
1955年 | 2篇 |
排序方式: 共有2870条查询结果,搜索用时 15 毫秒
181.
PT Lakkakorpi I Nakamura RM Nagy JT Parsons GA Rodan LT Duong 《Canadian Metallurgical Quarterly》1999,274(8):4900-4907
Bone resorption is initiated by osteoclast attachment to the mineralized matrix, cytoskeletal reorganization, cellular polarization, and the formation of the sealing zone. The present study examines the interaction between PYK2 and p130(Cas) (Crk-associated substrate), suggested to be part of the signaling pathway initiated by osteoclast adhesion. Using murine osteoclast-like cells (OCLs) and their mononuclear precursors (pOCs), generated in a co-culture of bone marrow and osteoblastic MB1.8 cells, we show that: 1) p130(Cas) is tyrosine-phosphorylated upon adhesion of pOCs to vitronectin or ligation of beta3 integrins; 2) p130(Cas) colocalizes with PYK2 and the cytoskeletal proteins F-actin, vinculin, and paxillin in the podosomal-rich ring-like structures of OCLs plated on glass and in the sealing zone in actively resorbing OCLs on bone; 3) p130(Cas) and PYK2 form a stable complex in pOCs, independent of tyrosine phosphorylation of either molecule, and this complex is present in Src (-/-) OCLs, in which neither protein is phosphorylated or associated with the osteoclast adhesion structure; 4) the association of p130(Cas) and PYK2 is mediated by the SH3 domain of p130(Cas) and the C-terminal domain of PYK2. These findings suggest that p130(Cas) and its association with PYK2 may play an important role in the adhesion-dependent signaling that leads to cytoskeletal reorganization and formation of the sealing zone during osteoclast activation. 相似文献
182.
GA Candeliere Y Rao A Floh SD Sandler JE Aubin 《Canadian Metallurgical Quarterly》1999,27(4):1079-1083
A cDNA fingerprinting strategy was developed to identify genes based on their differential expression pattern during osteoblast development. Preliminary biological and molecular staging of cDNA pools prepared by global amplification PCR allowed discrim-inating choices to be made in selection of expressed sequence tags (ESTs) to be isolated. Sequencing of selected ESTs confirmed that both known and novel genes can be isolated from any developmental stage of interest, e.g. from primitive progenitors, intermediate precursors or mature osteoblasts. EST expression provides insight into possible interrelated physiological functions and putative interacting molecules during differentiation. This method offers a functional genomics approach to isolate differentiation stage-specific genes in samples as small as a single cell. 相似文献
183.
184.
A rational approach to hemodialysis access in the patient with renal failure requires an understanding of many factors. The initial approach to such patients and subsequent decisions have a significant impact on quality of life as well as the morbidity of access choices. Autogenous vascular access remains the gold standard in the care of these patients. Alternatives are less desirable but are necessary in an increasing number of situations. Careful thought before embarking on a procedure will provide better long-term function and preserve the patient's options for the future. 相似文献
185.
186.
187.
188.
189.
VG Savchenko EN Parovichnikova VG Isaev IA Demidova RG Kuliev EO Gribanova GA Kliasova RA Kucher AN Sokolov KS Momotiuk IuV Ol''shanskaia NG Tiurina LIu Tikhonova GM Galstian VM Budianski? EA Belousov VA Lapin SV Voloshin TS Konstaninova LB Filatov ON Porokhina EA Smirnova 《Canadian Metallurgical Quarterly》1998,70(7):5-11
190.
MV Vasin GA Chernov LV Koroleva TS L''vova MM Abramov VV Antipov NN Suvorov 《Canadian Metallurgical Quarterly》1996,36(1):36-46
Output from the interpositus nucleus can inhibit the inferior olive, probably via the GABA-ergic nucleo-olivary pathway. It has been suggested that the function of this inhibition might be to regulate synaptic plasticity resulting from parallel fibre/climbing fibre interaction in cerebellar Purkinje cells, by providing negative feedback information to the olive. Thus, when a learned response, generated by the interpositus nucleus, reaches a sufficient amplitude, the olive would be inhibited and further learning blocked. This suggestion was tested in a classical conditioning paradigm. Decerebrate ferrets were trained using electrical skin stimulation of the forelimb as the conditioned stimulus (CS) and periorbital stimulation as the unconditioned stimulus (US). Climbing fibre responses evoked in Purkinje cells by the US were recorded as surface field potentials in the part of the c3 zone controlling eyeblink. It was found that the CS did not inhibit the olive at the beginning of training, but when conditioned responses were large, the olive was inhibited by the CS in some animals. After a number of unpaired CS presentations, which caused extinction of the conditioned response, the inhibition disappeared. The size of individual conditioned responses correlated negatively with the size of the climbing fibre responses evoked by the US. Climbing fibre responses evoked by direct stimulation of the olive were also inhibited. It was concluded that cerebellar output during performance of a conditioned response inhibits the inferior olive. The results thus support the hypothesis of a cerebellar locus of conditioning and are consistent with the proposed role of cerebello-olivary inhibition. 相似文献