全文获取类型
收费全文 | 238篇 |
免费 | 0篇 |
国内免费 | 2篇 |
专业分类
电工技术 | 3篇 |
化学工业 | 8篇 |
金属工艺 | 4篇 |
机械仪表 | 1篇 |
能源动力 | 1篇 |
轻工业 | 3篇 |
无线电 | 24篇 |
一般工业技术 | 6篇 |
冶金工业 | 185篇 |
自动化技术 | 5篇 |
出版年
2022年 | 1篇 |
2019年 | 2篇 |
2014年 | 2篇 |
2013年 | 3篇 |
2012年 | 3篇 |
2011年 | 4篇 |
2009年 | 1篇 |
2008年 | 1篇 |
2007年 | 1篇 |
2006年 | 4篇 |
2005年 | 2篇 |
2004年 | 1篇 |
2002年 | 2篇 |
2001年 | 1篇 |
2000年 | 1篇 |
1999年 | 5篇 |
1998年 | 48篇 |
1997年 | 30篇 |
1996年 | 19篇 |
1995年 | 10篇 |
1994年 | 9篇 |
1993年 | 10篇 |
1992年 | 7篇 |
1991年 | 3篇 |
1990年 | 9篇 |
1989年 | 7篇 |
1988年 | 3篇 |
1987年 | 6篇 |
1986年 | 4篇 |
1985年 | 5篇 |
1984年 | 1篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1980年 | 3篇 |
1979年 | 1篇 |
1977年 | 11篇 |
1976年 | 17篇 |
1975年 | 1篇 |
排序方式: 共有240条查询结果,搜索用时 15 毫秒
11.
DA Toke WL Bennett DA Dillon WI Wu X Chen DB Ostrander J Oshiro A Cremesti DR Voelker AS Fischl GM Carman 《Canadian Metallurgical Quarterly》1998,273(6):3278-3284
Diacylglycerol pyrophosphate (DGPP) is involved in a putative novel lipid signaling pathway. DGPP phosphatase (DGPP phosphohydrolase) is a membrane-associated 34-kDa enzyme from Saccharomyces cerevisiae which catalyzes the dephosphorylation of DGPP to yield phosphatidate (PA) and then catalyzes the dephosphorylation of PA to yield diacylglycerol. Amino acid sequence information derived from DGPP phosphatase was used to identify and isolate the DPP1 (diacylglycerol pyrophosphate phosphatase) gene encoding the enzyme. Multicopy plasmids containing the DPP1 gene directed a 10-fold overexpression of DGPP phosphatase activity in S. cerevisiae. The heterologous expression of the S. cerevisiae DPP1 gene in Sf-9 insect cells resulted in a 500-fold overexpression of DGPP phosphatase activity over that expressed in wild-type S. cerevisiae. DGPP phosphatase possesses a Mg2+-independent PA phosphatase activity, and its expression correlated with the overexpression of DGPP phosphatase activity in S. cerevisiae and in insect cells. DGPP phosphatase was predicted to be an integral membrane protein with six transmembrane-spanning domains. The enzyme contains a novel phosphatase sequence motif found in a superfamily of phosphatases. A dpp1Delta mutant was constructed by deletion of the chromosomal copy of the DPP1 gene. The dpp1Delta mutant was viable and did not exhibit any obvious growth defects. The mutant was devoid of DGPP phosphatase activity and accumulated (4-fold) DGPP. Analysis of the mutant showed that the DPP1 gene was not responsible for all of the Mg2+-independent PA phosphatase activity in S. cerevisiae. 相似文献
12.
GM McCarthy JD Awde H Ghandi M Vincent WI Kocha 《Canadian Metallurgical Quarterly》1998,34(6):484-490
Oral mucositis is a dose-limiting toxicity of 5-fluorouracil (5-FU). This prospective cohort study investigated factors associated with mucositis in patients receiving 5-FU for cancer of the digestive tract. Sixty-three patients (mean age 65 years) completed self-administered questionnaires and had interviews, oral examinations and unstimulated whole salivary flow measurements at baseline and follow-up appointments. The duration of follow-up was 2 months. Predictor variables included sociodemographic data, body surface area, diabetes, smoking, alcohol consumption, salivary flow, oral hygiene, presence of prostheses, performance status, regimen of cytotoxic drugs, hematological data, and herpes simplex virus antibody titer. Forty-six per cent of patients developed at least one episode of oral mucositis during cytotoxic treatment. Pearson's chi-square analysis showed that mucositis was significantly associated with xerostomia at baseline, xerostomia during chemotherapy, and lower baseline neutrophil counts (P < or = 0.05). Multiple logistic regression analysis indicated that xerostomia at baseline (odds ratio, OR = 10.0), or baseline neutrophil level under 4000 cells/mm3 (OR = 3.9) were significant predictors of mucositis. Taking into account the effect of neutrophil level at baseline, xerostomia during chemotherapy (OR = 4.5) was also a significant predictor of mucositis. The results showed that xerostomia and lower baseline neutrophil levels are significantly associated with oral mucositis. These variables should be taken into consideration in the design of intervention studies to reduce the frequency and severity of mucositis. More research is required to investigate the role of saliva and neutrophils in the pathogenesis of chemotherapy-induced mucositis. 相似文献
13.
14.
15.
WI Bensinger KS Schiffman L Holmberg FR Appelbaum R Maziarz P Montgomery E Ellis S Rivkin P Weiden K Lilleby S Rowley S Petersdorf JP Klarnet W Nichols A Hertler R McCroskey CH Weaver CD Buckner 《Canadian Metallurgical Quarterly》1997,19(12):1183-1189
The purpose of this study was to determine the outcome of patients with metastatic breast cancer treated with high-dose busulfan (Bu), melphalan (Mel) and thiotepa (TT) followed by peripheral blood stem cell (PBSC) infusion. Fifty-one patients with chemotherapy refractory (n = 32) or responsive (n = 19) metastatic breast cancer received Bu (12 mg/kg), Mel (100 mg/m2) and TT (500 mg/m2) followed by PBSC collected after chemotherapy and growth factor (n = 43) or growth factor alone (n = 8). The 100 day treatment-related mortality was 8% including one death from cytomegalovirus pneumonia, one from aspiration pneumonia and two from regimen-related toxicity (RRT). Seven of 28 refractory (25%) and 5/7 (71%) responsive patients with evaluable disease achieved a complete response of all measurable disease or all soft tissue disease with at least improvement in bone lesions (PR*). Fifteen of 51 patients (29%) are alive and progression-free a median of 423 days (range 353-934) after treatment, 5/32 (16%) with refractory disease and 10/19 (53%) with responsive disease. The probabilities of progression-free survival (PFS) at 1.5 years for the patients with refractory (n = 32) and responsive (n = 19) disease were 0.24 and 0.53, respectively. These preliminary data suggest that high-dose Bu/Mel/TT has significant activity in patients with advanced breast cancer and may be superior to some previously published regimens. 相似文献
16.
17.
BK Ganser S Li VY Klishko JT Finch WI Sundquist 《Canadian Metallurgical Quarterly》1999,283(5398):80-83
The genome of the human immunodeficiency virus (HIV) is packaged within an unusual conical core particle located at the center of the infectious virion. The core is composed of a complex of the NC (nucleocapsid) protein and genomic RNA, surrounded by a shell of the CA (capsid) protein. A method was developed for assembling cones in vitro using pure recombinant HIV-1 CA-NC fusion proteins and RNA templates. These synthetic cores are capped at both ends and appear similar in size and morphology to authentic viral cores. It is proposed that both viral and synthetic cores are organized on conical hexagonal lattices, which by Euler's theorem requires quantization of their cone angles. Electron microscopic analyses revealed that the cone angles of synthetic cores were indeed quantized into the five allowed angles. The viral core and most synthetic cones exhibited cone angles of approximately 19 degrees (the narrowest of the allowed angles). These observations suggest that the core of HIV is organized on the principles of a fullerene cone, in analogy to structures recently observed for elemental carbon. 相似文献
18.
19.
20.
WI Horne B Tandler MA Dubick O Niemel? GM Brittenham H Tsukamoto 《Canadian Metallurgical Quarterly》1997,64(2):90-102
Reproduction of pancreatic iron overload in an animal model has been difficult to achieve primarily because of the first-pass extraction of iron by the liver. We hypothesized that portacaval shunting would avoid this hepatic phenomenon and increase pancreatic iron deposition. An end-to-side portacaval shunt was surgically created in male Sprague-Dawley rats, and they were subsequently fed a carbonyl iron-supplemented diet for 17 weeks. This resulted in marked iron accumulation in the pancreas (1621 +/- 188 micrograms/g) compared to minimal deposition in sham-operated rats fed the same diet (138 +/- 53 micrograms/g). Iron deposition in the acinar and centroacinar cells was confirmed histologically by Gomori staining, as well as by ultrastructural examination. Iron overloading was associated with enhanced oxidative stress evidenced by a twofold increase in the levels of glutathione disulfide and thiobarbituric acid-reactive substances. Also, adducts of proteins with malondialdehyde and 4-hydroxynonenal were demonstrated in acinar and ductal cells. Other apparent consequences of iron overload were a 50% reduction in pancreatic amylase content and a decrease in pancreatic protein concentration. These hypotrophic changes were associated with a reduced mass of zymogen granules in the acinar cells noted histologically. Our results show that a combination of portacaval shunting and carbonyl iron feeding achieve pancreatic iron overload and support the role of oxidative stress in the pathogenesis of iron-induced damage in the pancreas. 相似文献