全文获取类型
收费全文 | 1157篇 |
免费 | 29篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 4篇 |
综合类 | 2篇 |
化学工业 | 101篇 |
金属工艺 | 16篇 |
机械仪表 | 35篇 |
建筑科学 | 4篇 |
矿业工程 | 2篇 |
能源动力 | 13篇 |
轻工业 | 25篇 |
水利工程 | 1篇 |
石油天然气 | 1篇 |
无线电 | 107篇 |
一般工业技术 | 82篇 |
冶金工业 | 740篇 |
原子能技术 | 7篇 |
自动化技术 | 47篇 |
出版年
2023年 | 6篇 |
2022年 | 7篇 |
2021年 | 8篇 |
2020年 | 9篇 |
2019年 | 10篇 |
2018年 | 17篇 |
2017年 | 6篇 |
2016年 | 23篇 |
2015年 | 14篇 |
2014年 | 17篇 |
2013年 | 20篇 |
2012年 | 27篇 |
2011年 | 39篇 |
2010年 | 19篇 |
2009年 | 28篇 |
2008年 | 24篇 |
2007年 | 23篇 |
2006年 | 20篇 |
2005年 | 14篇 |
2004年 | 15篇 |
2003年 | 16篇 |
2002年 | 13篇 |
2001年 | 14篇 |
2000年 | 10篇 |
1999年 | 36篇 |
1998年 | 223篇 |
1997年 | 125篇 |
1996年 | 75篇 |
1995年 | 37篇 |
1994年 | 49篇 |
1993年 | 35篇 |
1992年 | 9篇 |
1991年 | 11篇 |
1990年 | 8篇 |
1989年 | 14篇 |
1988年 | 15篇 |
1987年 | 6篇 |
1986年 | 4篇 |
1985年 | 3篇 |
1983年 | 6篇 |
1982年 | 2篇 |
1981年 | 6篇 |
1980年 | 16篇 |
1979年 | 2篇 |
1978年 | 5篇 |
1977年 | 29篇 |
1976年 | 67篇 |
1975年 | 2篇 |
1966年 | 1篇 |
1955年 | 1篇 |
排序方式: 共有1187条查询结果,搜索用时 15 毫秒
151.
ES Flamm HB Demopoulos ML Seligman JJ Tomasula V De Crescito J Ransohoff 《Canadian Metallurgical Quarterly》1977,46(3):328-335
Two models have been used to study the effects of ethanol on injuries of the central nervous system. The spinal cords of cats were injured by delivering a 200 gm-cm impact to the exposed dura mater. A second group of animals received a similar injury to the exposed dura mater overlying the cerebral hemispheres. The animals were divided into two groups, those that received an infusion of ethanol before injury, and control animals that received no ethanol. The parameters of injury used in this model produced small and insignificant lesions in those animals that received no ethanol; however, when the animals were pretreated with ethanol, a considerable increase in the extent of the injury was noted. These include alterations in membranes-bound enzymes and clotting mechanisms, and alteration of cell membranes through abnormal free radical reactions. 相似文献
152.
GO Korsrud HB Conacher GA Jarvis JL Beare-Rogers 《Canadian Metallurgical Quarterly》1977,12(2):177-181
A quantitative counterimmunoelectrophoresis technique has been applied to evaluation of RNA antibodies in serum and unconcentrated CSF. Serum anti-RNA antibodies have been found at high dilutions in some patients with infectious diseases, subacute panencephalitis and multiple sclerosis. RNA antibodies in CSF are significantly linked to oligoclonal aspect, i.e. to a synthesis of IgG inside the CNS. 相似文献
153.
SM Genuth HB Houser JR Carter I Merkatz JW Price OP Schumacher RG Wieland 《Canadian Metallurgical Quarterly》1976,25(12):1110-1117
The Diabetes Association of greater Cleveland screened 307,000 individuals in the metropolitan area for diabetes with a 75-gm. oral load of carbohydrate. Of these subjects 12,600 (4.1 per cent) had a two-capillary blood glucose level of greater than 139 mg. per cent and were defined as positive. Seventy per cent of the positives were retested, and 65 per cent of these again had two-hour levels greater than 139 mg. per cent. Seventy-one per cent of the original screening values were between 104 and 199 mg. per cent. The rate of positivity on retesting increased with the original screening bracket reaching 90 per cent at an original screening level of 240 mg. per cent or higher. The frequency of positive retests also increased with age irrespective of whether the original screening level was less than or greater than 200 mg. per cent. The implications of this large detection experience for conducting future mass surveys for diabetes are discussed. 相似文献
154.
155.
Neonatal encephalopathy following fetal distress. A clinical and electroencephalographic study 总被引:2,自引:0,他引:2
Twenty-one neonates of over 36 weeks' gestation suffered perinatal asphyxia but not chronic hypoxia. Three clinical stages of postanoxic encephalopathy were distinguished. Stage 1 lasted less than 24 hours and was characterized by hyperalertness, uninhibited Moro and stretch reflexes, sympathetic effects, and a normal electroencephalogram. Stage 2 was marked by obtundation, hypotonia, strong distal flexion, and multifocal seizures. The EEG showed a periodic pattern sometimes preceded by continuous delta activity. Infants in stage 3 were stuporous, flaccid, and brain stem and autonomic functions were suppressed. The EEG was isopotential or had infrequent periodic discharges. Infants who did not enter stage 3 and who had signs of stage 2 for less than five days appeared normal in later infancy. Persistence of stage 2 for more than seven days or failure of the EEG to revert to normal was associated with later neurologic impairment or death. 相似文献
156.
157.
Cryosurgery of bronchopulmonary structures. An approach to lesions inaccessible to the rigid bronchoscope 总被引:1,自引:0,他引:1
Cryonecrosis of the upper lobe of the lung and bronchi was safely inudced in healthy dogs by application of the cryoprobe to serosal surfaces or, through a bronchotomy, to the mucosal surfaces under direct vision. Seven days after cryosurgery, hyperemia of the bronchus was seen. By 14 days the bronchus at the target site was covered with cuboidal epithelium. Reappearance of normal ciliated epithelium occurred by 180 days after cryosurgery. Cartilage remained intact, and there was no evidence of formation of a stricture or other gross alteration of bronchial architecture. In the lung there was coagulation necrosis; and by 14 days after cryosurgery, there was fibrosis in the target area. There were no complications of the pleural space. Cryosurgery of tissues at the margins of the bronchotomy does not impair healing. Cryosurgery may reduce the necessity for extensive surgery in selected patients with bronchopulmonary tumors, including those inaccessible to the rigid bronchoscope. Clinically, eight patients with recurrent bronchogenic tumors have received palliation by transbronchoscopic cryosurgery. 相似文献
158.
159.
160.