全文获取类型
收费全文 | 1376篇 |
免费 | 2篇 |
专业分类
化学工业 | 12篇 |
轻工业 | 6篇 |
无线电 | 8篇 |
一般工业技术 | 2篇 |
冶金工业 | 1333篇 |
自动化技术 | 17篇 |
出版年
2019年 | 1篇 |
2016年 | 2篇 |
2013年 | 2篇 |
2010年 | 1篇 |
2006年 | 2篇 |
2005年 | 2篇 |
2004年 | 1篇 |
2003年 | 6篇 |
2002年 | 2篇 |
2000年 | 3篇 |
1999年 | 49篇 |
1998年 | 452篇 |
1997年 | 219篇 |
1996年 | 156篇 |
1995年 | 99篇 |
1994年 | 66篇 |
1993年 | 81篇 |
1992年 | 10篇 |
1991年 | 7篇 |
1990年 | 13篇 |
1989年 | 18篇 |
1988年 | 11篇 |
1987年 | 21篇 |
1986年 | 11篇 |
1985年 | 8篇 |
1984年 | 2篇 |
1983年 | 4篇 |
1982年 | 6篇 |
1981年 | 9篇 |
1980年 | 14篇 |
1978年 | 2篇 |
1977年 | 34篇 |
1976年 | 59篇 |
1975年 | 3篇 |
1972年 | 1篇 |
1962年 | 1篇 |
排序方式: 共有1378条查询结果,搜索用时 15 毫秒
51.
52.
53.
54.
55.
56.
Pulmonary angiograms and pulmonary lung perfusion scans on 162 patients with pulmonary embolism were comparatively analyzed. Among the expert angiographic panel members who independently evaluated the studies there was consistent agreement on the diagnosis, size of the emboli, and severity. Consistency of agreement among the expert pulmonary lung perfusion scan panelists was considerably less. These data demonstrate that, in addition to the lack of specificity of the lung perfusion scan for the diagnosis of pulmonary thromboemboli, there is a considerable problem of interpretation in this patient population. 相似文献
57.
58.
59.
Regional deposition of inhaled particles was studied experimentally in a hollow cast of the human larynx-tracheobronchial tree extending through the first six branching levels, and in twenty-six non-smoker human volunteers in vivo. Results of the hollow cast study indicated a linear dependence of particle deposition efficiency on the Stokes number for aerosols with aerodynamic diameters greater than 2 micrometers. Alveolar and total respiratory tract in vitro deposition in healthy non-smokers was minimal for particles of approximately 0.4 micrometers, and alveolar deposition for mouthpieces inhalations peaked for particles of approximately 3 micrometers. A new anatomic parameter, the bronchial deposition size (BDS), is introduced to permit the classification of various individuals and populations according to their tracheobronchial deposition efficiencies. The average BDS's were 1.20 cm for 26 healthy non-smokers, 1.02 cm for 46 cigarette smokers, 0.90 cm for 19 clinical patients being treated for obstructive lung disease and 0.60 cm for six severely disabled patients. 相似文献
60.
The in vitro inhibitory activity of rosamicin and erythromycin against 283 strains of nonfermenting, gram-negative bacilli was determined by using a broth dilution procedure. Rosamicin demonstrated greater activity than erythromycin against most strains tested. A number of species demonstrated significantly lower minimum inhibitory concentrations to rosamicin and would fall within the therapeutic range of the drug based on current pharmacological data. 相似文献