全文获取类型
收费全文 | 869篇 |
免费 | 0篇 |
专业分类
电工技术 | 1篇 |
化学工业 | 11篇 |
金属工艺 | 15篇 |
机械仪表 | 1篇 |
轻工业 | 4篇 |
无线电 | 1篇 |
冶金工业 | 835篇 |
自动化技术 | 1篇 |
出版年
2023年 | 1篇 |
2021年 | 1篇 |
2015年 | 1篇 |
2014年 | 1篇 |
2013年 | 4篇 |
2011年 | 1篇 |
2009年 | 1篇 |
2005年 | 1篇 |
2004年 | 2篇 |
2003年 | 2篇 |
1999年 | 18篇 |
1998年 | 273篇 |
1997年 | 146篇 |
1996年 | 96篇 |
1995年 | 51篇 |
1994年 | 43篇 |
1993年 | 44篇 |
1992年 | 7篇 |
1991年 | 10篇 |
1990年 | 4篇 |
1989年 | 9篇 |
1988年 | 10篇 |
1987年 | 11篇 |
1986年 | 13篇 |
1985年 | 11篇 |
1983年 | 2篇 |
1982年 | 3篇 |
1981年 | 2篇 |
1980年 | 13篇 |
1979年 | 4篇 |
1978年 | 2篇 |
1977年 | 21篇 |
1976年 | 53篇 |
1975年 | 3篇 |
1974年 | 1篇 |
1973年 | 1篇 |
1972年 | 1篇 |
1971年 | 1篇 |
1961年 | 1篇 |
排序方式: 共有869条查询结果,搜索用时 15 毫秒
151.
Effects of small cardioactive peptide B (SCPB) on cerebral neurons which underlie prey capture in the carnivorous pteropod mollusc, Clione limacina, were investigated. SCPB in concentrations of 10 microM and higher produced direct activation of cerebral ganglion neurons underlying extrusion of buccal cones used in prey capture. SCPB in lower concentrations, between 1 and 5 microM, did not have a noticeable effect on the membrane potentials of these neurons; however, it significantly increased their responsiveness to sensory inputs from the tactile stimulation of the head, and their ability to generate afterdischarge activity. SCPB immunoreactivity was observed in cell bodies in buccal, cerebral, pedal, and intestinal ganglia, as well as in the anterior esophagus and in buccal cones where fibers stained intensely. These electrophysiological and immunohistochemical data suggest that SCPB may have a physiological role in feeding arousal in Clione. 相似文献
152.
153.
154.
Emergency physicians need to understand the potential for false reassurance in the interpretation of reflex examination data. Neurologic consultation should be sought when classic signs are lacking, but other evidence causes suspicion. Changes in teaching emphasis and acute practice are needed, since the stakes may be high and time is of the essence. We have responded to the insights gained from this study by augmenting in-service and continuing medical education teaching and by implementing guidelines to assist EPs. We have emphasized the importance of spotlighting high-risk patients, as exemplified above, and of taking advantage of neurologic or neurosurgical consultation. Where in-person consultation is less available, the use of guidelines and remote consultation should be able to help direct further examination, diagnostic formulation, and the need for imaging decisions. Given the potential for severe negative outcome if spinal emergencies are not optimally managed, we must give the teaching of these issues high priority. 相似文献
155.
TP Berezina 《Canadian Metallurgical Quarterly》1998,84(9):940-948
In cats, distention of an isolated segment of the ileum with a saline injection elicited its contraction which could be abolished with blockade of muscarinic receptors. Serotonine acting from the ileum lumen enhanced the response, whereas acting from the vascular bed induced a contractile response which could be decreased with the beta-adrenoreceptor-blocking agent propranolol. The findings suggest a possibility of the serotonine participation in realisation of peristaltic reflex, the character of its modulating effect being dependent on activation of excitatory cholinergic and inhibitory nonadrenergic neurons. 相似文献
156.
OBJECTIVE: To determine the efficacy of acarbose, compared with placebo, on the metabolic control of NIDDM patients inadequately controlled on maximal doses of conventional oral agents. RESEARCH DESIGN AND METHODS: In this three-center double-blind study, 90 Chinese NIDDM patients with persistent poor glycemic control despite maximal doses of sulfonylurea and metformin were randomly assigned to receive additional treatment with acarbose 100 mg thrice daily or placebo for 24 weeks, after 6 weeks of dietary reinforcement. Efficacy was assessed by changes in HbA1c, fasting and 1-h postprandial plasma glucose and insulin levels, and fasting lipid levels. RESULTS: Acarbose treatment was associated with significantly greater reductions in HbA1c (-0.5 +/- 0.2% vs. placebo 0.1 +/- 0.2% [means +/- SEM], P = 0.038), 1-h postprandial glucose (-2.3 +/- 0.4 mmol/l vs. placebo 0.7 +/- 0.4 mmol/l, P < 0.001) and body weight (-0.54 +/- 0.32 kg vs. placebo 0.42 +/- 0.29 kg, P < 0.05). There was no significant difference between the two groups regarding changes in fasting plasma glucose and lipids or fasting and postprandial insulin levels. Flatulence was the most common side effect (acarbose vs. placebo: 28/45 vs. 11/44, P < 0.05). One patient on acarbose had asymptomatic elevations in serum transaminases that normalized in 4 weeks after acarbose withdrawal. Another patient on acarbose developed severe hypoglycemia; glycemic control was subsequently maintained on half the baseline dosage of sulfonylurea. CONCLUSIONS: In NIDDM patients inadequately controlled on conventional oral agents, acarbose in moderate doses resulted in beneficial effects on glycemic control, especially postprandial glycemia, and mean body weight. Additional use of acarbose can be considered as a useful alternative in such patients if they are reluctant to accept insulin therapy. 相似文献
157.
TP Duprez M Gille BC Vande Berg J Malghem CB Grandin P Michel S Ghariani BE Maldague 《Canadian Metallurgical Quarterly》1996,38(6):511-515
Low back pain is caused by a variety of etiologies. Some clinicians have postulated that much low back pain is due to trauma to the iliolumbar ligament. The iliolumbar ligament is one of the three pelvic-lumbar ligaments and develops during the 12th week of gestation. The iliolumbar ligament appears to be a major stabilizing component between the vertebral spine and the pelvis. The innervation of the iliolumbar ligament appears similar to the posterior lumbar ligaments. Our hypothesis is: micro-trauma to the iliolumbar ligament is the primary cause of many cases of chronic low back pain because (1) it is the weakest component of the multifidus triangle; (2) there is increased susceptibility to injury due to its angulated attachment; (3) it is a primary inhibitor of excess sacral flexion; (4) it is a highly innervated nociceptive tissue; and (5) it plays an increased role with progressive disc degeneration. 相似文献
158.
159.
160.
TP Tuomainen K Nyyss?nen R Salonen A Tervahauta H Korpela T Lakka GA Kaplan JT Salonen 《Canadian Metallurgical Quarterly》1997,20(3):426-428
OBJECTIVE: To study if there is an association between mildly elevated body iron and glucose homeostasis indexes. RESEARCH DESIGN AND METHODS: A cross-sectional population study was conducted in 1,013 middle-aged men, and an association of serum ferritin with concentrations of serum insulin, blood glucose, and serum fructosamine was tested. RESULTS: The mean concentration of fasting serum insulin was 21.6% higher (95% CI 7.3-37.9%, P < 0.001) in the 5th quintile of serum ferritin compared with the 1st quintile. The elevation in blood glucose was 6.1% (95% CI 2.3-9.9%, P < 0.001) and in serum fructosamine 3.9% (1.5-6.9%, P < 0.01). CONCLUSIONS: Mildly elevated body iron stores are associated with statistically significant elevations in glucose homeostasis indexes. 相似文献