全文获取类型
收费全文 | 7112篇 |
免费 | 11篇 |
专业分类
电工技术 | 2篇 |
化学工业 | 121篇 |
金属工艺 | 8篇 |
机械仪表 | 13篇 |
建筑科学 | 17篇 |
矿业工程 | 4篇 |
能源动力 | 5篇 |
轻工业 | 34篇 |
水利工程 | 15篇 |
石油天然气 | 1篇 |
无线电 | 56篇 |
一般工业技术 | 59篇 |
冶金工业 | 6727篇 |
原子能技术 | 4篇 |
自动化技术 | 57篇 |
出版年
2021年 | 3篇 |
2019年 | 5篇 |
2018年 | 6篇 |
2016年 | 4篇 |
2014年 | 8篇 |
2013年 | 23篇 |
2012年 | 12篇 |
2011年 | 16篇 |
2010年 | 10篇 |
2009年 | 12篇 |
2008年 | 13篇 |
2007年 | 22篇 |
2006年 | 14篇 |
2005年 | 14篇 |
2004年 | 13篇 |
2003年 | 20篇 |
2002年 | 12篇 |
2001年 | 10篇 |
2000年 | 15篇 |
1999年 | 169篇 |
1998年 | 1969篇 |
1997年 | 1156篇 |
1996年 | 781篇 |
1995年 | 411篇 |
1994年 | 364篇 |
1993年 | 402篇 |
1992年 | 60篇 |
1991年 | 115篇 |
1990年 | 120篇 |
1989年 | 101篇 |
1988年 | 112篇 |
1987年 | 99篇 |
1986年 | 91篇 |
1985年 | 73篇 |
1984年 | 20篇 |
1983年 | 18篇 |
1982年 | 43篇 |
1981年 | 53篇 |
1980年 | 65篇 |
1979年 | 9篇 |
1978年 | 37篇 |
1977年 | 192篇 |
1976年 | 365篇 |
1975年 | 19篇 |
1974年 | 8篇 |
1973年 | 3篇 |
1971年 | 3篇 |
1970年 | 4篇 |
1955年 | 4篇 |
1954年 | 3篇 |
排序方式: 共有7123条查询结果,搜索用时 0 毫秒
1.
GW Pratt 《Canadian Metallurgical Quarterly》1997,(23):30-32
A discussion is presented of contributing factors to the injury to the foreleg of the Thoroughbred racehorse. The critical part of the step is taken to be the first 10-20 ms after ground contact as the hoof slides forward and stops. Large nonaxial loads associated with the deceleration of the hoof are shown to arise. Results of accelerometer measurements on the hoof of a horse running at racing speed are presented as well as mechanical properties of the racing surface. The mechanical properties of the track surface, the type of shoe, and the degree of fatigue of the horse all work together to determine the level of risk. 相似文献
2.
Assuming that the chemical reactions used to synthesize a combinatorial library member are successful, then knowledge of the specific reaction sequence is equivalent to knowing the member's chemical identity. Because the determination of chemical identity is typically not automatable and requires a substantial amount of material, schemes that encode a member's reaction history onto the reaction platform are of value. The primary benefits of encoding are relational nomenclature (all methods) and automated handling (some methods). Encoding methods evaluated to date are spatial, graphical, chemical, spectrometric, electronic, and physical. 相似文献
3.
OBJECTIVES: To assess that neuromuscular relaxation onset of the adductor pollicis (AP) is related to neuromuscular stimulation rate. To assess that train-of-four (TOF) at 0.05 Hz is a more accurate indicator of optimal tracheal intubation time and conditions, than TOF at 0.08 Hz. STUDY DESIGN: Prospective, comparative, randomized double-blind study. PATIENTS: Forty adults, physical class ASA 1 or 2, undergoing general anaesthesia with tracheal intubation were allocated to two groups (n = 20) according to the sequence of stimulation of the AP: either TOF at 0.05 Hz (test group) or TOF at 0.08 Hz (control group). METHODS: Induction of anaesthesia was achieved with thiopentone, fentanyl and vecuronium (0.1 mg.kg-1). Neuromuscular monitoring was obtained with force displacement transducers attached to each AP. Tracheal intubation was performed once AP muscular response obtained with TOF at 0.05 Hz for test group and TOF at 0.08 Hz for control group was abolished. Results are expressed as mean +/- SEM. Fisher exact test was used for intubation conditions comparison. Curarization time between groups was compared with unpaired Student's t test (P < 0.05 accepted). RESULTS: TOF with 0.05 Hz stimulation significantly increased curarization time: 217 +/- 7 versus 162 +/- 6 s (P < 0.001). Intubation conditions were excellent in 95% and good in 5% of patients in the study group, compared to 15 and 40% in the control group, respectively (P < 0.01) in 45% of the control group patients coughing at intubation occurred. CONCLUSION: Low stimulation rate (TOF at 0.05 Hz) of AP is a reliable technique to determine the appropriate intubation time for patients paralyzed with vecuronium. 相似文献
4.
5.
6.
7.
An innovative method for modelling biological processes under anaerobic conditions is presented and discussed. The method is based on titrimetric and off-gas measurements. Titrimetric data is recorded as the addition rate of hydroxyl ions or protons that is required to maintain pH in a bioreactor at a constant level. An off-gas analysis arrangement measures, among other things, the transfer rate of carbon dioxide. The integration of these signals results in a continuous signal which is solely related to the biological reactions. When coupled with a mathematical model of the biological reactions, the signal allows a detailed characterisation of these reactions, which would otherwise be difficult to achieve. Two applications of the method to the enhanced biological phosphorus removal processes are presented and discussed to demonstrate the principle and effectiveness of the method. 相似文献
8.
9.