全文获取类型
收费全文 | 796篇 |
免费 | 0篇 |
国内免费 | 3篇 |
专业分类
电工技术 | 6篇 |
化学工业 | 3篇 |
金属工艺 | 3篇 |
轻工业 | 1篇 |
一般工业技术 | 1篇 |
冶金工业 | 784篇 |
自动化技术 | 1篇 |
出版年
2019年 | 1篇 |
2016年 | 1篇 |
2011年 | 1篇 |
2008年 | 1篇 |
2003年 | 1篇 |
1999年 | 18篇 |
1998年 | 235篇 |
1997年 | 153篇 |
1996年 | 108篇 |
1995年 | 46篇 |
1994年 | 39篇 |
1993年 | 36篇 |
1992年 | 6篇 |
1991年 | 11篇 |
1990年 | 10篇 |
1989年 | 14篇 |
1988年 | 5篇 |
1987年 | 4篇 |
1986年 | 8篇 |
1985年 | 7篇 |
1983年 | 2篇 |
1982年 | 3篇 |
1981年 | 1篇 |
1980年 | 10篇 |
1979年 | 1篇 |
1978年 | 2篇 |
1977年 | 20篇 |
1976年 | 52篇 |
1975年 | 1篇 |
1972年 | 1篇 |
1955年 | 1篇 |
排序方式: 共有799条查询结果,搜索用时 0 毫秒
81.
82.
83.
The effect of the neuroprotective kappa opioid agonist CI-977 on glutamate (GLU)-stimulated calcium signaling was studied in individual primary rat cortical neurons. Using laser scanning confocal microscopy and the fluorescent calcium probe fluo-3, both the sustained and biphasic intracellular calcium concentration [Ca2+]i changes induced by GLU (20-40 microM) were altered by CI-977 (25-100 nM), thereby shifting the neuronal population response from unbuffered to buffered patterns of [Ca2+]i flux. This effect was consistent with the previously demonstrated neuroprotective action of CI-977 against glutamate toxicity in vitro. The effect of CI-977 in altering GLU-induced [Ca2+]i signaling was attenuated by naloxone, consistent with a neuroprotective action of CI-977 at opioid receptors, presumably of the kappa subtype. 相似文献
84.
R Coszach T Delbar W Galster P Leleux I Licot E Liénard P Lipnik C Michotte A Ninane J Vervier CR Bain T Davinson RD Page AC Shotter PJ Woods D Baye F Binon P Descouvemont P Duhamel J Vanhorenbeeck M Vincke P Decrock M Huyse Van Duppen P G Vancraeynest FC Barker 《Canadian Metallurgical Quarterly》1994,50(3):1695-1701
85.
Our previous study indicated that 5-hydroxytryptamine (5-HT) immunoreactive fiber densities were decreased in specific areas of the brain in alcohol-preferring rats (P) when compared with alcohol-nonpreferring rats (NP). The results of our current study show that there are quantitative and qualitative differences in 5-HT innervation in other selected regions of the forebrains of P rats. The 5-HT fiber density in the brains of young adult P and NP rats was measured by immunocytochemistry and quantitative image analysis. A routine error of two-dimensional quantitation of nerve fiber was addressed and an adjustment was made. The amount of 5-HT fibers was significantly lower in CA4 and fasciola cinereum of the dorsal hippocampus, caudate-putamen, and hypothalamus of the P as compared with NP rats (unpaired Student's t tests). In examining the fiber types, we found that, in the frontal cortical and hippocampal regions, where normally fine 5-HT fibers with small varicosities and thick 5-HT fibers with large varicosities coexist, fewer fine 5-HT fibers were seen in P rats as compared with NP rats. The fine fibers are known to be vulnerable to abusive drugs. These observations indicate that (a) there are quantitative differences in 5-HT innervation or that the 5-HT in some 5-HT fibers is reduced to a level undetectable by immunocytochemistry, and (b) the fine 5-HT fibers are specifically reduced to a greater degree in the selected brain regions of P rats when compared with that of NP rats. The involvement of the 5-HT system in the alcohol abuse is discussed. 相似文献
86.
JF DeFrance S Sands FC Schweitzer L Ginsberg JC Sharma 《Canadian Metallurgical Quarterly》1997,9(4):283-293
The purpose of this article is to deliberate the moral and legal dilemma entailed in the weapon of the labour strike as a pressure tactic on the Israeli Finance Ministry regarding job slots, budgets and, in effect, violating the collective agreement signed by the nurses and impairing patients' treatment, as opposed to refraining from striking and suffering the heavy burden of work, the lack of trained personnel, low wages, and the inability to give patients proper, high quality treatment. 相似文献
87.
BACKGROUND: The use of kidneys from non-heartbeating donors (NHB) remains controversial. An increased incidence of delayed primary function and primary nonfunction is common. We report a characteristic syndrome of transaminitis and thrombocytopenia after NHB renal transplantation, which may be predictive of graft outcome. METHODS: Two case histories are presented, followed by a retrospective analysis of 38 NHB renal grafts performed at Guy's Hospital from 1988 to 1994. Changes in alanine aminotransferase (ALT) and platelet count were compared between recipients of kidneys from NHB and heartbeating donors (HB). To control for possible effects of antilymphocyte globulin (ALG), two matched control groups receiving HB kidneys with (n=32) and without (n=32) ALG were also compared. RESULTS: ALT was elevated in 32 of 38 (84%) of NHB recipients and 19 of 64 (30%) controls (P<0.001). Mean peak ALT was 172+/-20 U/L in NHB and 42+/-6 U/L in HB kidneys (P<0.001). Use of ALG did not influence mean peak ALT. Elevated ALT predicted impaired graft function (P<0.02) and was associated with an increased length of delayed primary function (P<0.001) and risk of transplant nephrectomy (P<0.05). Thrombocytopenia (<100 x 10(9) cells/L) occurred in 18 of 38 (47%) NHB recipients and in 20 of 64 (31%) controls (P<0.05). Mean nadir platelet count (x 10(9) cells/L) was 113+/-10 in NHB, 128+/-9 in HB with ALG, and 164+/-9 in HB without ALG (both P<0.05 vs. NHB). Patients who underwent graft nephrectomy (n=9) had a disproportionate fall in platelet count (mean nadir, 80+/-11 x 10(9) cells/L; P<0.05). CONCLUSIONS: Transaminitis and thrombocytopenia occur commonly after NHB kidney transplantation and are predictive of graft outcome. Recognition of these changes may assist the early management of NHB renal recipients, and also reduce investigation of "anomalous" results in this setting. 相似文献
88.
I Khairoun MG Boltong FC Driessens JA Planell 《Canadian Metallurgical Quarterly》1997,18(23):1535-1539
Clinical requirements for calcium phosphate bone cements were formulated in terms of the initial setting time, the final setting time, the cohesion time and the ultimate compressive strength. Three cement formulations were tested. The previously developed Biocement H was made of a powder containing alpha-tertiary calcium phosphate and precipitated hydroxyapatite. Biocement B2 powder was made by adding some CaCO3 to Biocement H, whereas Biocement B1 was made by adding some CaCO3 but with simultaneous adjustment of the amount of precipitated hydroxyapatite.The liquid/ powder ratio of the cement paste and the accelerator concentrations (percentage Na2HPO4) in cement liquid were varied. For Biocement H there was no combination of L/P ratio and percentage Na2HPO4 for which all clinical requirements were satisfied. However, there was an area of full compliance for Biocements B1 and B2, of which that for B1 was the largest. Therefore, Biocement B1 may be applied in clinical situations as those in orthopaedics, plastic and reconstructive surgery and oral and maxillofacial surgery, even when early contact with blood is inevitable. 相似文献
89.
90.
The sensitivity of the single intradermal comparative tuberculin test, as applied in the Republic of Ireland, was estimated in 353 cattle with tuberculous lesions. These cattle had been removed from 47 herds which were depopulated owing to chronic or extensive infection with Mycobacterium bovis. The test had a sensitivity of 90.9 per cent, because 321 (90.9 per cent) of the 353 cattle with tuberculous lesions gave a positive or inconclusive result, and 32 gave a negative result. These 32 negative cattle came from 17 (36 per cent) of the 47 depopulated herds. 相似文献