全文获取类型
收费全文 | 435篇 |
免费 | 2篇 |
国内免费 | 2篇 |
专业分类
电工技术 | 3篇 |
综合类 | 3篇 |
化学工业 | 19篇 |
金属工艺 | 3篇 |
机械仪表 | 1篇 |
建筑科学 | 11篇 |
矿业工程 | 2篇 |
能源动力 | 5篇 |
轻工业 | 17篇 |
石油天然气 | 1篇 |
无线电 | 4篇 |
一般工业技术 | 17篇 |
冶金工业 | 343篇 |
自动化技术 | 10篇 |
出版年
2019年 | 2篇 |
2016年 | 2篇 |
2015年 | 3篇 |
2014年 | 3篇 |
2013年 | 6篇 |
2012年 | 2篇 |
2011年 | 9篇 |
2010年 | 5篇 |
2008年 | 6篇 |
2007年 | 9篇 |
2006年 | 7篇 |
2005年 | 4篇 |
2004年 | 7篇 |
2003年 | 3篇 |
2002年 | 2篇 |
2001年 | 2篇 |
2000年 | 2篇 |
1999年 | 12篇 |
1998年 | 91篇 |
1997年 | 49篇 |
1996年 | 33篇 |
1995年 | 19篇 |
1994年 | 23篇 |
1993年 | 23篇 |
1992年 | 4篇 |
1991年 | 5篇 |
1990年 | 6篇 |
1989年 | 6篇 |
1988年 | 4篇 |
1987年 | 5篇 |
1985年 | 4篇 |
1984年 | 3篇 |
1983年 | 3篇 |
1982年 | 3篇 |
1981年 | 1篇 |
1980年 | 3篇 |
1979年 | 4篇 |
1978年 | 2篇 |
1977年 | 8篇 |
1976年 | 30篇 |
1975年 | 2篇 |
1974年 | 3篇 |
1973年 | 1篇 |
1972年 | 2篇 |
1971年 | 3篇 |
1969年 | 1篇 |
1968年 | 3篇 |
1967年 | 1篇 |
1943年 | 1篇 |
1928年 | 1篇 |
排序方式: 共有439条查询结果,搜索用时 9 毫秒
21.
BACKGROUND: The place of acid pump inhibitors at the top of the efficacy table in the league of reflux therapies, and their eager patient acceptance, has aroused debate on their role. OBJECTIVE: To understand the role of gastric acid and its inhibition in the pathogenesis and treatment of gastroesophageal reflux disease. DISCUSSION: Gastroesophageal reflux disease results from excessive exposure of the oesophagus to acidic contents. Acid pump inhibitors provide the most effective medical control of gastric acid throughout day and night, returning oesophageal pH to normal levels. They provide fast symptom relief and rapidly restore quality of life in all reflux patients more effectively than H2 receptor antagonists or prokinetic drugs. APIs heal oesophagitis of all grades of severity and provide safe, effective maintenance of healing with prevention of complications in longer term use. 相似文献
22.
23.
HI Pass DJ Mew KC Kranda BK Temeck JS Donington SA Rosenberg 《Canadian Metallurgical Quarterly》1996,61(6):1609-1617
BACKGROUND: A phase I trial was initiated to define the feasibility and safety of single-lung isolation perfusion with tumor necrosis factor-alpha, interferon-gamma, and moderate hyperthermia for patients with unresectable pulmonary metastases. METHODS: Twenty patients with lung metastases (Ewing's, 2; sarcoma, 8; melanoma, 6; other, 4) were considered for single-lung isolation perfusion with 0.3 to 6.0 mg of tumor necrosis factor-alpha and 0.2 mg interferon-gamma delivered through an oxygenated pump circuit. Sixteen perfusions were performed in 15 patients (bilateral in 1). Metastases were completely resected (no single-lung isolation perfusion) in 3 patients, 1 patient had extrapulmonary disease, and one single-lung isolation perfusion was aborted for mechanical reasons. RESULTS: There were no significant changes in systemic arterial blood pressure or cardiac output during perfusion. Systolic pulmonary artery pressure increased with isolation, but returned to pre-single-lung isolation perfusion levels after clamp release. The maximum systemic tumor necrosis factor-alpha level was 8 ng/mL, whereas pump-circuit levels ranged from 200 to 10,976 ng/mL. There were no deaths, and the mean hospitalization period was 9 days (range, 5 to 34 days). A short-term (6 to 9 month) unilateral decrease in perfused nodules was noted in 3 patients (melanoma in 1, adenoid cystic carcinoma in 1, renal cell carcinoma in 1). CONCLUSIONS: Future studies using a combination of biologic modifiers, chemotherapy, and hyperthermia should be pursued to define active cytotoxic agents that will preserve underlying pulmonary function. 相似文献
24.
25.
At the Gesellschaft für Schwerionenforschung, Darmstadt, an eight-pole interconnection for active vacuum gauges and corresponding controllers was standardized in collaboration with industry. It is suited for available gauges and gauges under development, which cover the whole technically interesting pressure range 103–1012 mbar. The interconnection contains the power lines for the gauge, the pressure signal as well as control lines for the various gauges. Just one type of connector is used thus facilitating stock keeping and use of different gauges. The chosen connector (known as modular connector) can be easily assembled without soldering. Furthermore, an encoder resistor installed in the gauge head allows an identification of the gauge by the controller. In this way, different gauges may be operated by the same controller or by the same PC plug-in module. 相似文献
26.
Grotzinger J.; Engels M.; Jacoby E.; Wollmer A.; Strassburger W. 《Protein engineering, design & selection : PEDS》1991,4(8):1021
A printer's error was introduced into the title of this articlewhen it was in press. The correct title is as follows. A model for the C5a receptor and for its interaction with theligand* An omission was also made on the second line of the first columnon page 769. This and the subsequent four lines should readas follows. pairing of Cys86(B) with Cys109(C) or Cys285(G), but stronglysuggest that with either Cys293 or Cys294(G). A choice can bemade with arguments given below. Pairing with Cys285(G), forinstance, would require a vertical relative shift of two helixturns which would immerse polar side chains in the membrane. 相似文献
27.
28.
29.
The feasibility of generating substituted phenyl radicals and biradicals (with a charged substituent) in the gas phase by laser photolysis was examined by using a Fourier-transform ion cyclotron resonance mass spectrometer. The precursors were generated by ipso-substitution of a halogen atom in the radical cation of a di- or trihalobenzene by various nucleophiles. Photolytic cleavage of the remaining carbon-halogen bond(s) with 266-nm radiation was found to produce many substituted phenyl radicals in greater yields than the earlier employed method, sustained off-resonance irradiated collision-activated dissociation (SORI-CAD). Furthermore, ion generation by photolysis leads to isomerization less often than collisional activation. Finally, not only phenyl-bromine and phenyl-iodine but also certain phenyl-chlorine bonds can be cleaved by photolysis, whereas the synthetic utility of SORI-CAD appears to be largely limited to the cleavage of phenyl-iodine bonds. Hence, laser photolysis greatly expands the variety of substituted phenyl radicals and biradicals that can be synthesized inside a mass spectrometer. 相似文献
30.
It has been observed that the occurrence of respiratory complications and diarrhoea among measles cases has changed over time but this change has not been quantified. A study was carried out in the city of Gweru, Zimbabwe, to quantify these changes. Rates of respiratory complications and diarrhoea among measles cases were determined in each year for the period 1968-89. It was found that mean rates of respiratory complications and diarrhoea during 1968-78 were 17.2 per cent (95 per cent CI = 11.6-22.8) and 5.2 per cent (95 per cent CI = 0-11) respectively while during 1979-89, mean rates of respiratory complications and diarrhoea were 6.5 per cent (95 per cent CI = 1-12.1) and 16.4 per cent (95 per cent CI = 10.1-22.0) respectively. Analysis of variance (ANOVA) to determine the main effects and the interaction showed that the main effects were not statistically significant (F = 0.01, d.f.1,2 = 1,40, p = 0.935; and F = 0.13, d.f.1,2 = 1,40, p = 0.725 respectively) Meanwhile the interaction term of complications and period was statistically significant (F = 15.7, d.f.1,2 = 1,40, p < 0.001). It was concluded that a change in rates of respiratory complications and diarrhoea had occurred among measles cases. It is suggested that the increase in vaccination coverage in 1979-89 and the shift in age at infection to older age groups in the same period may have brought about this change through selective suppression of respiratory complications among measles cases. 相似文献