全文获取类型
收费全文 | 3187篇 |
免费 | 6篇 |
专业分类
电工技术 | 1篇 |
综合类 | 2篇 |
化学工业 | 28篇 |
金属工艺 | 7篇 |
机械仪表 | 9篇 |
建筑科学 | 4篇 |
能源动力 | 10篇 |
轻工业 | 23篇 |
水利工程 | 4篇 |
石油天然气 | 3篇 |
无线电 | 25篇 |
一般工业技术 | 16篇 |
冶金工业 | 3020篇 |
原子能技术 | 5篇 |
自动化技术 | 36篇 |
出版年
2023年 | 2篇 |
2022年 | 11篇 |
2021年 | 4篇 |
2020年 | 5篇 |
2019年 | 3篇 |
2018年 | 3篇 |
2017年 | 7篇 |
2016年 | 7篇 |
2015年 | 4篇 |
2014年 | 3篇 |
2013年 | 18篇 |
2012年 | 9篇 |
2011年 | 8篇 |
2010年 | 4篇 |
2009年 | 6篇 |
2008年 | 3篇 |
2007年 | 10篇 |
2005年 | 6篇 |
2004年 | 7篇 |
2003年 | 5篇 |
2002年 | 12篇 |
2001年 | 5篇 |
2000年 | 5篇 |
1999年 | 93篇 |
1998年 | 837篇 |
1997年 | 461篇 |
1996年 | 301篇 |
1995年 | 187篇 |
1994年 | 130篇 |
1993年 | 203篇 |
1992年 | 35篇 |
1991年 | 41篇 |
1990年 | 39篇 |
1989年 | 59篇 |
1988年 | 46篇 |
1987年 | 47篇 |
1986年 | 47篇 |
1985年 | 49篇 |
1983年 | 3篇 |
1982年 | 15篇 |
1981年 | 36篇 |
1980年 | 32篇 |
1979年 | 2篇 |
1978年 | 7篇 |
1977年 | 106篇 |
1976年 | 247篇 |
1975年 | 14篇 |
1968年 | 1篇 |
1963年 | 1篇 |
1955年 | 4篇 |
排序方式: 共有3193条查询结果,搜索用时 15 毫秒
61.
62.
A retrospective analysis of 89 patients who underwent jejunoileal bypass surgery for morbid obesity disclosed 33 complications that were detected radiographically. Intestinal obstruction (10.1% of patients), cholecystitis (5.6%), renal stones (4.5%), peptic ulcer (3.4%), megacolon (6.7%), and elongation of the small intestine with hypertrophy of the mucosal folds of the jejunum (6.7%) were diagnosed solely by radiographic means. 相似文献
63.
64.
Whole ovaries from 16-day fetal mice were cultured for 6 to 20 days and then transplanted to the kidneys of ovariectomized adult mice where they remained for one to four weeks. After three weeks in the host's kidneys, many follicles developed within the transplants and became vesiculated. Many of the oocytes within these follicles had formed the first metaphase spindle of meiosis and several had completed the first polar body. Host mice bearing transplants that contained vesiculated follicles showed uterine stimulation and keratinization of their vaginae. However, ovaries that had been in culture for more than ten days before transplantation showed a limited response to the gonadotropins and never matured sufficiently to stimulate the host's reproductive tract. No ovulations occurred in any of the transplants. 相似文献
65.
A review of all granulomatous surgical lesions in the files of the Free University Hospital revealed four cases of histoplasmoma in which Grocott-staining procedures provided histologic confirmation of the presence of Histoplasma capsulatum bodies. The case histories have been presented briefly. A short review of the literature follows. 相似文献
66.
Optic disk vasculitis 总被引:1,自引:0,他引:1
A 44-year-old woman developed progressive loss of vision associated initially with a swollen optic disk, and later with optic atrophy and a diffuse retinal vasculopathy, which caused extensive retinal hemorrhagagic. Histopathologic examination showed hemorrhagagic infarction of the retina, as well as infarction of the anterior optic nerve. In the optic nerve, the central retinal vessels showed extensive phlebitis and occlusion of many small arterioles. 相似文献
67.
68.
69.
70.