全文获取类型
收费全文 | 6281篇 |
免费 | 1篇 |
专业分类
综合类 | 1篇 |
化学工业 | 22篇 |
建筑科学 | 1篇 |
轻工业 | 1篇 |
石油天然气 | 1篇 |
无线电 | 2篇 |
一般工业技术 | 6篇 |
冶金工业 | 6244篇 |
自动化技术 | 4篇 |
出版年
2019年 | 1篇 |
2015年 | 2篇 |
2013年 | 2篇 |
2010年 | 1篇 |
2009年 | 1篇 |
2007年 | 1篇 |
2005年 | 2篇 |
2004年 | 3篇 |
2003年 | 17篇 |
2002年 | 1篇 |
2001年 | 1篇 |
2000年 | 1篇 |
1999年 | 202篇 |
1998年 | 1983篇 |
1997年 | 1081篇 |
1996年 | 777篇 |
1995年 | 401篇 |
1994年 | 333篇 |
1993年 | 365篇 |
1992年 | 41篇 |
1991年 | 87篇 |
1990年 | 49篇 |
1989年 | 67篇 |
1988年 | 64篇 |
1987年 | 65篇 |
1986年 | 67篇 |
1985年 | 48篇 |
1983年 | 6篇 |
1982年 | 24篇 |
1981年 | 38篇 |
1980年 | 62篇 |
1979年 | 6篇 |
1978年 | 16篇 |
1977年 | 135篇 |
1976年 | 314篇 |
1975年 | 11篇 |
1973年 | 1篇 |
1955年 | 5篇 |
1954年 | 1篇 |
排序方式: 共有6282条查询结果,搜索用时 15 毫秒
111.
Patients' perceptions of quality are important to the performance ratings, financial viability, and operational options afforded to purchasers of health care. Through TRICARE, the Department of Defense provides care for the more than 1.5 million active duty service members charged with the defense of the nation. As patients, these service members are typically incapable of assessing the technical quality of the care they receive. This study examines the attributes of health care delivery that define military patients' perceptions of quality and discusses the implications of these assessments. 相似文献
112.
JL Wright LM Lawson PD Pare BJ Wiggs S Kennedy JC Hogg 《Canadian Metallurgical Quarterly》1983,127(4):474-477
To investigate the effect of smoking status on pulmonary function and pathologic changes in the peripheral airways, we studied 97 patients who underwent thoracotomy for coin lesions. The patients were divided into 4 groups: nonsmokers (n = 9), current smokers (n = 51), and those who had ceased smoking for less than (n = 18) or more than (n = 19) 2 yr prior to surgery. We found that current smokers had evidence of air-flow obstruction with abnormal lung volumes when compared with nonsmokers. Ex-smokers had lung volumes similar to those of nonsmokers, but showed evidence of obstruction, with the FEV1/FVC between the values found for nonsmokers and current smokers. Examination of the small airways showed that the membranous bronchioles of current smokers and ex-smokers displayed only increased goblet cell metaplasia when compared with those in nonsmokers; the respiratory bronchioles of current and ex-smokers showed increases in intraluminal and airway wall inflammatory cells, wall fibrosis, and pigment deposition. We conclude that patients who currently smoke cigarettes have reduced lung function that is associated with abnormalities of airway structure. Although those who have stopped smoking have function that is closer to the nonsmoking group, there is no apparent difference in structural change between current and ex-smokers. 相似文献
113.
Three-dimensional motion and reconstruction of coronary arteries from biplane cineangiography 总被引:3,自引:0,他引:3
A new approach is described for reconstructing coronary arteries from two sequences of projection images. The estimation of motion is performed on three-dimensional line segments (or centrelines), and is based on a ‘predictionprojection-optimization’ loop. The method copes with time varying properties, deformations and superpositions of vessels. Experiments using simulated and real data have been carried out. and the results found to be robust over a full cycle of a human heart. Local and global kinetic features can then be derived to obtain a greater insight on the cardiac functional state 相似文献
114.
These studies were designed to determine the effect of acute alcohol treatment on gestational length and to probe for a mechanism underlying alcohol-induced early onset of parturition (EOP) in mice. Experiment 1: alcohol increases the incidence of EOP. Pregnant C57BL/6J mice were given alcohol (0, 4, 5 or 6 g kg(-1), i.g.) on Gestational Day (GD) 10, 15, 16, 17 or 18. Deliveries were monitored every 6 h from GD 18. Results indicated that 6 g kg(-1) alcohol treatment on GD 17 or 18 increased the incidence of EOP. Experiment 2: prostaglandins (PGs) play roles in parturition. The purpose of Experiment 2 was to determine whether PGs mediate alcohol-induced EOP in mice. The results indicated that pretreatment on GD 17 with aspirin, a prostaglandin synthesis inhibitor, prevented alcohol-induced EOP. These data suggest that alcohol-induced EOP in mice may be mediated by PGs. Experiment 3: PGs are influenced by alcohol and are triggers of labour. Experiment 3 measured uterine PGs associated with the onset of alcohol-induced EOP in mice. Alcohol increased uterine PGE and PGF2alpha, with PGE levels higher than control before labour, and elevated PGF2alpha levels correlating with labour. Changes in gestational length have important implications for pregnancy outcome, as well as for normal fetal growth and development. 相似文献
115.
116.
117.
118.
119.
120.
van Hemmen JL 《Canadian Metallurgical Quarterly》1987,36(4):1959-1962