全文获取类型
收费全文 | 2416篇 |
免费 | 7篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 1篇 |
综合类 | 2篇 |
化学工业 | 30篇 |
金属工艺 | 7篇 |
机械仪表 | 5篇 |
建筑科学 | 8篇 |
能源动力 | 3篇 |
轻工业 | 26篇 |
水利工程 | 2篇 |
石油天然气 | 1篇 |
无线电 | 12篇 |
一般工业技术 | 22篇 |
冶金工业 | 2279篇 |
原子能技术 | 4篇 |
自动化技术 | 22篇 |
出版年
2023年 | 1篇 |
2020年 | 1篇 |
2019年 | 1篇 |
2018年 | 2篇 |
2017年 | 2篇 |
2016年 | 5篇 |
2014年 | 9篇 |
2013年 | 18篇 |
2012年 | 8篇 |
2011年 | 4篇 |
2010年 | 8篇 |
2009年 | 9篇 |
2008年 | 6篇 |
2007年 | 4篇 |
2006年 | 6篇 |
2005年 | 2篇 |
2004年 | 5篇 |
2003年 | 6篇 |
2002年 | 7篇 |
2001年 | 6篇 |
2000年 | 1篇 |
1999年 | 77篇 |
1998年 | 756篇 |
1997年 | 428篇 |
1996年 | 246篇 |
1995年 | 142篇 |
1994年 | 116篇 |
1993年 | 141篇 |
1992年 | 14篇 |
1991年 | 29篇 |
1990年 | 33篇 |
1989年 | 25篇 |
1988年 | 36篇 |
1987年 | 34篇 |
1986年 | 19篇 |
1985年 | 25篇 |
1984年 | 1篇 |
1983年 | 4篇 |
1982年 | 10篇 |
1981年 | 11篇 |
1980年 | 17篇 |
1979年 | 1篇 |
1978年 | 3篇 |
1977年 | 45篇 |
1976年 | 92篇 |
1975年 | 4篇 |
1971年 | 1篇 |
1970年 | 1篇 |
1969年 | 1篇 |
1960年 | 1篇 |
排序方式: 共有2424条查询结果,搜索用时 0 毫秒
51.
Gaucher's disease is a lysosomal storage disease in which cells of the reticuloendothelial system accumulate the lipid glucocerebroside. It is characterized by slowly progressive visceral and osseous involvement. One of the latter manifestations includes lipid infiltration of bone marrow. We monitored the rate of inhaled 133Xe uptake and wash-out over diseased and normal metaphyseal and epiphyseal areas of the knee. Twenty-two patients (15 adults, 7 children) with various degrees of previously diagnosed Gaucher's disease were positioned supine under a gamma-camera interfaced to a computer system. All patients rebreathed 133Xe gas from a closed system for 10 min followed by 14 min of wash-out. Digitized images of the lung, liver, spleen, bony sites and soft tissue were obtained at 1 min intervals during the wash-in and wash-out phases. Counts for each ROI were normalized per 100 pixels and plotted as a function (time). Maximum uptake was also calculated by relating the counts/ROI/100 pixels to the 10 min integrated lung count during equilibrium (the administered "dose"). There was essentially no 133Xe uptake in liver and spleen involved with Gaucher's disease. Monophasic uptake and biphasic wash-out curves were observed in the limited investigative population. Skeletal Gaucher deposits released the 133Xe at a greater rate relative to soft tissue. 相似文献
52.
The concept of cardiac reconditioning centers for the prevention and rehabilitation of coronary patients has been tremendously successful in Germany over the past 20 years. At least 40 such centers are located throughout the country. Physicians, nurses, and physical therapists work closely together in the various facets of the rehabilitation process. The financial backing for these facilities is primarily through governmental and regional insurance companies, whose officials are apparently convinced that in the long run supporting preventive measures is financially sound. Objective data supporting their convictions come from studies such as that of Brusis, who showed that such as that of 1,500 employees was diminished by nearly 70 percent during a two-year period after cardiac reconditioning, as compared to a similar time period before the rehabilitation experience. Subjective benefits, which are extremely difficult to quantitate in meaningful terms, were nonetheless expressed by nearly all the patients with whom I conversed. Perhaps they have experienced the same feelings that Mark Twain did when he observed that "all frets and worries and chafings sank to sleep in the presence of the benignant serenity of the Alps; the Great Spirit of the Mountains breathed his own peace upon their hurt minds and sore hearts and healed them." 相似文献
53.
KA Peter 《Canadian Metallurgical Quarterly》1998,25(3):8-13
In 1936, when Eila Hopper Ross (nee Hopper) was putting the final stroke of paint on her six-foot oil canvas of a life model at the Ontario College of Art, she had not dreamed that in the year to follow she would embark upon a life's career of anatomical study and attention to intricate detail in her own work as a medical illustrator. Though she had early aspirations herself of going into medicine--having been raised in a medical environment with her father, Dr. David Alexander Hopper, regularly receiving pharmaceutical literature with impressive illustrations--Hopper Ross was not aware of medical illustration as a profession. It was Maria Wishart, then director of the Medical Art Service Unit at the University of Toronto, who saw Hopper Ross' final exhibition at the Ontario College of Art and recommended she consider a career in medical art. As a result, Hopper Ross studied for two years (1937-1939) in the Department of Art as Applied to Medicine at Johns Hopkins University in Baltimore, Maryland under the direction of Professor Max Br?del. 相似文献
54.
55.
J Wayne H Suh Z Misulovin KA Sokol K Inaba MC Nussenzweig 《Canadian Metallurgical Quarterly》1994,1(2):95-107
Effects of etoposide (VP-16) and cytosine arabinoside (Ara-C) on the cell cycle of HL-60 and THP-1 cells were studied by flow cytometry using the bromodeoxyuridine (BrdU)/DNA assay technique to investigate the efficacy of VP-16 for monocytic leukemia cells. VP-16 inhibited the proliferation of THP-1 cells more strongly than that of HL-60 cells at any concentrations used at 24 and 48 hr. VP-16 arrested HL-60 and THP-1 cells in the G2/M phase and reduced them in the G0/G1 and early S phase at higher concentrations. There was no significant difference in the percentage of G2/M phase cells at the same concentration between both cells. However, reduction in the G0/G1 and early S phase cells was more marked in THP-1 than HL-60 cells significantly. On the other hand, Ara-C perturbed the cell cycle of HL-60 cells more than that of THP-1 cells at 24 and 48 hr. These results suggest that the effects of VP-16 on the cell cycle may be more intense in THP-1 than HL-60 cells, and support the efficacy of VP-16 for treating monocytic leukemia in vivo. 相似文献
56.
One of the major challenges facing cloud computing is to accurately predict future resource usage to provision data centers for future demands. Cloud resources are constantly in a state of flux, making it difficult for forecasting algorithms to produce accurate predictions for short times scales (ie, 5 minutes to 1 hour). This motivates the research presented in this paper, which compares nonlinear and linear forecasting methods with a sequence prediction algorithm known as a recurrent neural network to predict CPU utilization and network bandwidth usage for live migration. Experimental results demonstrate that a multitime-ahead prediction algorithm reduces bandwidth consumption during critical times and improves overall efficiency of a data center. 相似文献
57.
ABSTRACT: The ability of 13 different strains of psychrotrophs to release free fatty acids in milk was evaluated by using GC analysis. The 13 strains could be categorized into 3 groups: Group 1 consisted of bacteria that grew well and released large quantities of free fatty acids, group 2 consisted of bacteria that grew well but released low amounts of free fatty acids, and group 3 consisted of bacteria that did not grow well nor released large quantities of fatty acids. In group 1, 3 strains were determined to be highly lipolytic, releasing short‐chain fatty acids in amounts greater than reported threshold values. Group 3 consisted of 2 strains, which did not grow well in heat‐treated milk, and the subsequent release of free fatty acids was minor during the 10‐d monitoring time. The other 8 strains tested showed no specific pattern of fatty acid release and quantities of short‐chain fatty acids were not large, despite the ability to grow to high numbers in the treated milk. This work indicates that the lipolytic activity of psychrotrophs common in raw milk is specific to the species and a general prediction of free fatty acid release may not be possible. 相似文献
58.
59.
MG Otto AD Mayer PA Clavien A Cavallari KA Gunawardena EA Mueller 《Canadian Metallurgical Quarterly》1998,66(12):1632-1640
60.
KA Cook TE Dobbs WG Hlady JG Wells TJ Barrett ND Puhr GA Lancette DW Bodager BL Toth CA Genese AK Highsmith KE Pilot L Finelli DL Swerdlow 《Canadian Metallurgical Quarterly》1998,280(17):1504-1509
CONTEXT: Acidic foods such as orange juice have been thought to be unlikely vehicles of foodborne illness. OBJECTIVE: To investigate an outbreak of Salmonella enterica serotype Hartford (Salmonella Hartford) infections among persons visiting a theme park in Orlando, Fla, in 1995. DESIGN: Review of surveillance data, matched case-control study, laboratory investigation, and environmental studies. SETTING: General community. PARTICIPANTS: The surveillance case definition was Salmonella Hartford or Salmonella serogroup C1 infection in a resident of or a visitor to Orlando in May or June 1995. In the case-control study, case patients were limited to theme park hotel visitors and controls were matched to case patients by age group and hotel check-in date. MAIN OUTCOME MEASURES: Risk factors for infection and source of implicated food. RESULTS: Sixty-two case patients from 21 states were identified. Both Salmonella Hartford and Salmonella enterica serotype Gaminara (Salmonella Gaminara) were isolated from stool samples of 1 ill person. Thirty-two case patients and 83 controls were enrolled in the case-control study. Ninety-seven percent of case patients had drunk orange juice in the theme park vs 54% of controls (matched odds ratio, undefined; 95% confidence interval, 5.2 to undefined). The orange juice was unpasteurized and locally produced. Salmonella Gaminara was isolated from 10 of 12 containers of orange juice produced during May and July, indicating ongoing contamination of juice probably because of inadequately sanitized processing equipment. CONCLUSIONS: Unpasteurized orange juice caused an outbreak of salmonellosis in a large Florida theme park. All orange juice was recalled and the processing plant closed. Pasteurization or other equally effective risk-management strategies should be used in the production of all juices. 相似文献