全文获取类型
收费全文 | 1310篇 |
免费 | 9篇 |
专业分类
电工技术 | 4篇 |
化学工业 | 16篇 |
金属工艺 | 6篇 |
机械仪表 | 15篇 |
建筑科学 | 6篇 |
能源动力 | 9篇 |
轻工业 | 55篇 |
水利工程 | 2篇 |
无线电 | 10篇 |
一般工业技术 | 24篇 |
冶金工业 | 1149篇 |
原子能技术 | 1篇 |
自动化技术 | 22篇 |
出版年
2023年 | 2篇 |
2022年 | 4篇 |
2021年 | 4篇 |
2020年 | 5篇 |
2019年 | 4篇 |
2018年 | 5篇 |
2017年 | 4篇 |
2016年 | 5篇 |
2015年 | 2篇 |
2014年 | 7篇 |
2013年 | 29篇 |
2012年 | 11篇 |
2011年 | 10篇 |
2010年 | 10篇 |
2009年 | 7篇 |
2008年 | 14篇 |
2007年 | 3篇 |
2006年 | 1篇 |
2005年 | 3篇 |
2004年 | 2篇 |
2003年 | 3篇 |
2002年 | 2篇 |
2000年 | 1篇 |
1999年 | 28篇 |
1998年 | 374篇 |
1997年 | 171篇 |
1996年 | 131篇 |
1995年 | 69篇 |
1994年 | 49篇 |
1993年 | 71篇 |
1992年 | 8篇 |
1991年 | 17篇 |
1990年 | 9篇 |
1989年 | 8篇 |
1988年 | 13篇 |
1987年 | 11篇 |
1986年 | 12篇 |
1985年 | 16篇 |
1984年 | 1篇 |
1983年 | 4篇 |
1982年 | 6篇 |
1981年 | 7篇 |
1980年 | 13篇 |
1979年 | 3篇 |
1978年 | 7篇 |
1977年 | 47篇 |
1976年 | 101篇 |
1975年 | 2篇 |
1965年 | 2篇 |
1955年 | 1篇 |
排序方式: 共有1319条查询结果,搜索用时 9 毫秒
981.
982.
983.
984.
DH Bagley EL Felix WF Sindelar JL Doppman AS Ketcham 《Canadian Metallurgical Quarterly》1977,39(4):1743-1747
Charts of 566 patients admitted to the Surgery Branch, National Cancer Institute over a five year period were reviewed. Routine upper gastrointestinal series was performed in 453 patients; barium enemas in 490; and proctosigmoidoscopies in 342. Upper gastrointestinal series detected no metastases or second primary malignancies but delineated the extent of large intra-abdominal tumors. Barium enema and proctosigmoidoscopy together revealed three unsuspected primary colonic tumors (1.2% in patients over 50 years of age). Sigmoidoscopy and examination of the stool for occult blood would have detected the same patients. Barium enema may be limited to surgical cancer patients in whom the extent of local tumor invasion is to be defined and to older patients in whom colonic tumors are suspected. Neither UGIS nor barium enema appear to be of value as a routine preoperative screening test in surgical cancer patients. 相似文献
985.
986.
EL Lowell 《Canadian Metallurgical Quarterly》1976,121(3):309-311
The somitic mesoderm of the wing level was replaced in a two-day chick embryo by quail somitic mesoderm obtained from the level of the wing, the leg or the neck. The musculature of the host's wing on the operated side was exclusively or almost exclusively constituted by quail cells, whereas the skeleton, the dermis, the tendons and the muscular envelopes were formed by chick cells. This result demonstrates that, under the present experimental conditions, the wing musculature is originated from the somitic mesoderm of any level of the cephalocaudal axis. 相似文献
987.
988.
HH Kaufman EL Reilly HP Porecha KG Khalil G Van Horn 《Canadian Metallurgical Quarterly》1977,7(4):195-198
Electroencephalographic monitoring of a patient during carotid endarterectomy demonstrated severe ipsilateral voltage suppression with preservation of rhythms when the common carotid artery was clamped. Because the atheromatous plaque extended almost to the base of the skull, it was impossible to insert a shunt. Occlusion time was 19 minutes. After carotid flow was re-established, there was a rapid recovery of voltage. The patient awoke with a profound hemiparesis, but this cleared almost completely within a week. The EEG changes indicated severe ischemia, but, though function was transiently impaired, there was no apparent cerebral necrosis. This case represents the most severe yet reversible episode of ischemia during carotid clamping reported to date. Preservation of EEG rhythms, even in the face of voltage suppression, may have been a favorable sign. 相似文献
989.
F Gottsauner-Wolf EL Egger MD Markel FM Schultz EY Chao 《Canadian Metallurgical Quarterly》1994,65(2):179-184
For the purpose of developing a method to attach tendons directly to the prosthesis, canine supraspinatus tendons were attached in vitro to a metallic surface, using 3 different fixation devices: a spiked polyacetal washer (Synthes), a spiked soft tissue fixation plate (Synthes), and a newly designed Enhanced Tendon Anchor (ETA), which straddled the tendon with interlocking spikes oriented at a 20-degree angle. 2 methods were used: 1) the tendon was fixed directly to the metallic surface, or 2) a bone block containing the tendon insertion was fixed to the metallic surface. The specimens were tested for initial fixation strength in tension to failure; intact bone-muscle-tendon-bone units were used as controls. Bone block fixations were stronger than direct tendon fixations when the spiked washer or the ETA was used; this was not true of the fixation plate. The ETA was stronger than the other techniques in ultimate strength in both direct tendon fixation and bone block fixation. The soft tissue fixation plate was found to be weaker than the other techniques in bone block fixation. 相似文献
990.
EL Abel 《Canadian Metallurgical Quarterly》1994,56(4):795-800
Rats were tested in the forced swim test in 35 or 20 cm of water or in an open field to evaluate the effects of different intensities of stress on blood gases, electrolytes, and metabolic indices, compared to nontested controls. Animals tested in the open field did not differ from controls on any measure. Immersion in deep water resulted in a greater mixed metabolic and respiratory acidemia (low pH, low bicarbonate, high pCO2), higher glucose and higher lactate levels than immersion in shallow water which in turn resulted in greater metabolic acidemia (low pH, low bicarbonate), and higher glucose and lactate levels than occurred in open field or control animals. In contrast to immersion in deep water, immersion in shallow water resulted in an initial hypocapnia followed by a hypercapnia. Immersion in deep water also resulted in higher potassium levels, lower bicarbonate and total carbon dioxide levels, and a higher anion gap than immersion in shallow water, testing in the open field, or in controls. In a second study, lactate infusion resulted in a metabolic alkalemia (increased pH and bicarbonate levels) and an increase in total carbon dioxide levels. These results indicate that test parameters from forced swim testing (e.g., water depth) can significantly affect the rat's physiological response to testing. The effects of forced swim testing are not simply due to general stress; and the physiological changes seen in conjunction with forced swim testing (e.g., acidemia) are not due to lactate alone. 相似文献