全文获取类型
收费全文 | 1975篇 |
免费 | 0篇 |
国内免费 | 1篇 |
专业分类
化学工业 | 16篇 |
金属工艺 | 1篇 |
机械仪表 | 3篇 |
建筑科学 | 1篇 |
轻工业 | 18篇 |
一般工业技术 | 10篇 |
冶金工业 | 1918篇 |
原子能技术 | 1篇 |
自动化技术 | 8篇 |
出版年
2022年 | 1篇 |
2013年 | 6篇 |
2012年 | 2篇 |
2011年 | 5篇 |
2009年 | 1篇 |
2008年 | 2篇 |
2007年 | 3篇 |
2006年 | 6篇 |
2005年 | 4篇 |
2004年 | 4篇 |
2003年 | 7篇 |
2002年 | 2篇 |
2001年 | 1篇 |
1999年 | 49篇 |
1998年 | 582篇 |
1997年 | 307篇 |
1996年 | 244篇 |
1995年 | 149篇 |
1994年 | 105篇 |
1993年 | 105篇 |
1992年 | 19篇 |
1991年 | 39篇 |
1990年 | 34篇 |
1989年 | 18篇 |
1988年 | 26篇 |
1987年 | 31篇 |
1986年 | 27篇 |
1985年 | 34篇 |
1982年 | 4篇 |
1981年 | 7篇 |
1980年 | 10篇 |
1978年 | 4篇 |
1977年 | 27篇 |
1976年 | 104篇 |
1975年 | 6篇 |
1955年 | 1篇 |
排序方式: 共有1976条查询结果,搜索用时 0 毫秒
101.
102.
103.
104.
105.
106.
107.
108.
Neurofibromatosis type 2 (NF2) is a dominantly inherited disorder characterized by the occurrence of bilateral acoustic neuromas (ANs and other central nervous system tumors. Magnetic resonance images and audiologic data on 22 patients with NF2 who underwent multiple studies at the National Institutes of Health between 1983 and 1993 were reviewed to determine the growth characteristics of ANs in these patients. The average growth rate of ANs in NF2 patients was 0.30 cm3 per year and was significantly higher in older patients (0.75 cm3 per year) than in younger ones (0.12 cm3 per year). Larger ANs were more commonly found in patients with concomitant spinal tumors or meningiomas. NF2 patients with spinal tumors but not meningiomas demonstrated faster growth rates than patients without additional tumor burden. The data from this study suggest that older patients or patients with associated spinal tumors have faster growing ANs and therefore should be followed closely and treated aggressively. 相似文献
109.
Case-control methodology was used to assess lung cancer risk from exposure to arsenic in air, employing data from former workers in different units at the Chuquicamata copper mine and smelter complex. Thirty two workers from this complex were identified among the lung cancer deaths that occurred in the Northern region of Chile between 1987 and 1991. Each case was matched on age and sex, with controls that had a similar date of enrolment in the company. Available data on arsenic concentrations in air for six work sites were compiled from 1952 to 1991 and these were used to categorize the workplaces: Administrative area (1.6 micrograms/m3), Mine (2.3 micrograms/m3), Oxid Plant (3.1 micrograms/m3), Workshop and Services (9.8 micrograms/m3), Sulphur Plant (8.4 micrograms/m3) and Smelter (201.7 micrograms/m3). The results indicate an Odds Ratio of 5.7 (Fisher's p = 0.016) of dying from lung cancer among workers of the smelter compared with the rest of the workers. 相似文献
110.