全文获取类型
收费全文 | 1593篇 |
免费 | 7篇 |
专业分类
电工技术 | 9篇 |
化学工业 | 29篇 |
金属工艺 | 5篇 |
机械仪表 | 11篇 |
建筑科学 | 8篇 |
能源动力 | 2篇 |
轻工业 | 17篇 |
水利工程 | 3篇 |
石油天然气 | 1篇 |
无线电 | 25篇 |
一般工业技术 | 59篇 |
冶金工业 | 1406篇 |
原子能技术 | 5篇 |
自动化技术 | 20篇 |
出版年
2023年 | 2篇 |
2021年 | 3篇 |
2018年 | 2篇 |
2017年 | 2篇 |
2016年 | 2篇 |
2013年 | 9篇 |
2012年 | 6篇 |
2011年 | 10篇 |
2010年 | 3篇 |
2009年 | 5篇 |
2008年 | 7篇 |
2007年 | 3篇 |
2006年 | 5篇 |
2005年 | 5篇 |
2004年 | 4篇 |
2003年 | 8篇 |
2002年 | 10篇 |
2001年 | 5篇 |
2000年 | 4篇 |
1999年 | 42篇 |
1998年 | 374篇 |
1997年 | 234篇 |
1996年 | 147篇 |
1995年 | 77篇 |
1994年 | 88篇 |
1993年 | 87篇 |
1992年 | 12篇 |
1991年 | 31篇 |
1990年 | 33篇 |
1989年 | 24篇 |
1988年 | 44篇 |
1987年 | 29篇 |
1986年 | 19篇 |
1985年 | 23篇 |
1984年 | 9篇 |
1983年 | 11篇 |
1982年 | 11篇 |
1981年 | 15篇 |
1980年 | 11篇 |
1979年 | 2篇 |
1978年 | 3篇 |
1977年 | 60篇 |
1976年 | 94篇 |
1975年 | 6篇 |
1974年 | 4篇 |
1973年 | 2篇 |
1969年 | 2篇 |
1967年 | 2篇 |
1965年 | 1篇 |
1955年 | 2篇 |
排序方式: 共有1600条查询结果,搜索用时 15 毫秒
21.
LB To N Horvath P Dyson J Henry P Sykes M Brisco A Morley B Bennetts 《Canadian Metallurgical Quarterly》1996,5(5):557-559
Autologous transplantation has been used increasingly over the last 10 years for the treatment of multiple myeloma. As is the case in other cancers treated by high-dose therapy and stem cell rescue, the contribution of occult tumor cells in the graft to relapse posttransplant remains to be resolved. In this report, we review the biology and differentiation of plasma cells in the context of their significance as an origin of relapse in multiple myeloma. 相似文献
22.
23.
TW Gardner DA Quillen GW Blankenship WK Marshall 《Canadian Metallurgical Quarterly》1993,100(7):1050-1054
PURPOSE: The purposes of this study are to measure real-time intraocular pressure (IOP) during scleral buckling and to determine the effects of elevated IOPs on ocular perfusion. PATIENTS AND METHODS: A standard 4-mm, 20-gauge infusion cannula was inserted through the pars plana, connected to a standard hemodynamic monitoring unit with an electronic pressure transducer, and calibrated. The authors measured real-time IOP in 20 eyes undergoing scleral buckling surgery for primary rhegmatogenous retinal detachments and determined the IOP required to close the central retinal artery. Pressure measurements were read from the monitor videoscreen intraoperatively and from a continuous paper tracing postoperatively. RESULTS: The patients ranged in age from 24 to 88 years (mean, 59.7 years). The highest IOP elevations occurred during scleral depression and cryopexy, ranging up to 210 mmHg (mean, 116 mmHg). Pressures at which the central retinal artery closed ranged from 48 to 110 mmHg (mean, 79.2 mmHg). Manipulations of the globes caused IOPs greater than the central retinal artery perfusion pressures in 13 of the 20 patients. The duration of pressures in excess of the central retinal artery perfusion pressure ranged from 6 to 402 seconds (mean, 118.8 seconds). There were no intraoperative or postoperative complications from the infusion cannula. CONCLUSIONS: Conventional scleral buckling surgery causes wide fluctuations in IOP and may impair ocular perfusion. Additional studies are needed to determine the long-term consequences of these pressure elevations. 相似文献
24.
25.
26.
27.
28.
29.
E Danielsen R Bauer L Hemmingsen MJ Bjerrum T Butz W Tr?ger GW Canters T Den Blaauwen G Van Pouderoyen 《Canadian Metallurgical Quarterly》1995,233(2):554-560
The present work uses 111mCd-perturbed angular correlations of gamma-rays (PAC) to investigate the structure of the metal site of the His117Gly mutant of Pseudomonas aeruginosa azurin in aqueous solution and the effect on the structure upon addition of the following exogenous ligands: imidazole, 4-methyl imidazole, 1-methyl imidazole, 2-methyl imidazole and histidine. The nuclear quadrupole interaction of cadmium bound to the mutant without addition of exogenous ligands shows a strong pH dependence with three different nuclear quadrupole interactions consistent with two pKa values at about 7.2 and 8.6 at 2 degrees C. Addition of the imidazole derivatives resulted in a significant change in the PAC spectrum showing that they coordinate. This is in accordance with observations by EPR for the same mutant with copper at the metal site [den Blaauwen, T. & Canters, G. W. (1993) J. Am. Chem. Soc. 115, 1121-1129]. However, whereas EPR and ultraviolet/visual absorption show that the characteristics of the wild-type copper protein are regained by addition of the imidazole derivatives with the exception of the possible bidentates (histidine and histamine), the comparison of the PAC results to model calculations shows that the cadmium ion must be fourfold coordinated in most cases, probably binding an additional water or hydroxide ligand. A fourfold coordination is in contrast to cadmium-substituted wild-type azurin where PAC data inferred a threefold coordination by a Cys and two His residues [Danielsen, E. Bauer, R., Hemmingsen, L., Andersen. M., Bjerrum, M. J., Butz, T., Tr?ger, W., Canters, G. W., Hoitink, C. W. G., Karlsson, G., Hansson, O. & Messerschmidt, A. (1995) J. Biol. Chem. 270, 573-580] 相似文献
30.