全文获取类型
收费全文 | 1166篇 |
免费 | 5篇 |
专业分类
化学工业 | 17篇 |
金属工艺 | 1篇 |
机械仪表 | 3篇 |
建筑科学 | 3篇 |
能源动力 | 2篇 |
轻工业 | 23篇 |
无线电 | 1篇 |
一般工业技术 | 6篇 |
冶金工业 | 1103篇 |
原子能技术 | 5篇 |
自动化技术 | 7篇 |
出版年
2021年 | 1篇 |
2020年 | 1篇 |
2018年 | 2篇 |
2017年 | 4篇 |
2016年 | 1篇 |
2015年 | 3篇 |
2013年 | 10篇 |
2012年 | 2篇 |
2011年 | 3篇 |
2008年 | 6篇 |
2007年 | 1篇 |
2006年 | 1篇 |
2005年 | 1篇 |
2004年 | 3篇 |
2003年 | 6篇 |
2002年 | 2篇 |
2001年 | 2篇 |
2000年 | 1篇 |
1999年 | 42篇 |
1998年 | 357篇 |
1997年 | 209篇 |
1996年 | 115篇 |
1995年 | 73篇 |
1994年 | 65篇 |
1993年 | 66篇 |
1992年 | 11篇 |
1991年 | 16篇 |
1990年 | 12篇 |
1989年 | 16篇 |
1988年 | 12篇 |
1987年 | 9篇 |
1986年 | 11篇 |
1985年 | 7篇 |
1984年 | 2篇 |
1983年 | 5篇 |
1982年 | 4篇 |
1981年 | 5篇 |
1980年 | 4篇 |
1978年 | 5篇 |
1977年 | 20篇 |
1976年 | 51篇 |
1965年 | 1篇 |
1955年 | 2篇 |
1954年 | 1篇 |
排序方式: 共有1171条查询结果,搜索用时 15 毫秒
91.
92.
OBJECTIVE: Our purpose was to evaluate flow-induced responses, myogenic tone, and norepinephrine-induced constriction in myometrial resistance arteries from normal term pregnant women and the role that nitric oxide and prostanoids may play in these responses. STUDY DESIGN: Arteries (approximately 200 microns, n = 14, at 40 mm Hg) were dissected from myometrial biopsy specimens from women undergoing cesarean section and then were mounted in a pressure arteriograph. Responses to intraluminal flow, pressure, and a constrictor agonist (norepinephrine 10(-6) mol/L) were studied in the absence and presence of N omega-nitro-L-arginine methyl ester (n = 7) or indomethacin (n = 5). Myogenic and norepinephrine-induced tone were calculated after the determination of artery diameter in the absence of extracellular calcium. RESULTS: Arteries developed myogenic tone (80 mm Hg) that was not modulated by nitric oxide or prostanoid release, whereas norepinephrine-induced tone was significantly enhanced by the nitric oxide inhibitor. An increase in intraluminal flow led to dilatation in physiologic salt solution and indomethacin, but to constriction in the presence of N omega-nitro-L-arginine methyl ester (percent increase in diameter at flow rate of 184.6 microliters/min, 24% +/- 8% in physiologic salt solution and 20% +/- 4% in the presence of indomethacin versus -27% +/- 12% in N omega-nitro-L-arginine methyl ester alone and -21% +/- 10% in indomethacin and N omega-nitro-L-arginine methyl ester, respectively, analysis of variance, p < 0.05). CONCLUSIONS: Flow-induced shear stress is a physiologic modulator of vascular tone in myometrial arteries from pregnant women. Nitric oxide, but not prostanoids, mediates this response and also blunts norepinephrine constriction. Nitric oxide may play a fundamental role in the maintenance of adequate blood supply to the fetus during human pregnancy. 相似文献
93.
94.
95.
KR Edge CP McClarty SJ Krige RR Rantalainan 《Canadian Metallurgical Quarterly》1995,33(3):117-9; discussion 119-20
Four hundred and eight consecutive patients scheduled for cataract surgery under local anaesthesia were randomly allocated to one of two types of regional anaesthesia. One group was given the standard retrobulbar block combined with a facial nerve block of the O'Brien type, and the second group was given a modified peribulbar block. Results indicate that it is possible to achieve a high degree of reliability, within a relatively short time, from the modified peribulbar block without the major complications associated with retrobulbar block. 相似文献
96.
97.
KR Geisinger 《Canadian Metallurgical Quarterly》1995,103(3):295-299
Assessment of compliance in drug taking is a problem in a crowded Outpatient Department. Using riboflavin as a urinary marker is a simple and rational method. Identifying riboflavin in the urine by fluorescence on exposure to ultraviolet (UV) rays or torch light is being used in medical practice but not extensively. In this study, the validity and reliability of these methods were assessed. The sensitivity and specificity of this test by UV method was 86% and 82% for Reader I (medical person) and 82% and 94% for Reader II (paramedical person). For Reader I, the accuracy of reading by UV lamp was the same as torch light (85%) whereas for Reader II the accuracy was better with UV lamp (87%) than with torch (79%). In reading the fluorescence by UV lamp the crude agreement between the 2 readers was 82% and chance corrected agreement was 64%. UV lamp method appears to be a reliable way of assessing compliance both by medical and paramedical persons whereas torch method appears to be more reliable when used by a medical person than by a paramedical person. 相似文献
98.
99.
DA Cherry JL Plummer GK Gourlay KR Coates CL Odgers 《Canadian Metallurgical Quarterly》1995,62(1):119-121
A double-blind multidose trial of the addition of ketamine (0-40 mg, i.m., 8 times per day) to intramuscular morphine therapy was undertaken in a 61-year-old man with chronic back pain related to osteoporosis who had received inadequate pain relief from anterior interbody fusion, dorsal column stimulation and morphine alone. The patient reported only mild side effects. Nausea, tiredness and well-being were not significantly influenced by the ketamine dose level. Visual analogue pain scores prior to each dose were not associated with the ketamine dose level, but pain scores 30 min after doses were significantly reduced in a dose-related manner. In addition, the amount of morphine used by the patient was significantly reduced as the ketamine dose increased. This patient experienced substantial benefit from the addition of ketamine to intramuscular morphine therapy. 相似文献
100.