全文获取类型
收费全文 | 1519篇 |
免费 | 0篇 |
专业分类
化学工业 | 9篇 |
轻工业 | 4篇 |
无线电 | 1篇 |
一般工业技术 | 2篇 |
冶金工业 | 1503篇 |
出版年
2022年 | 1篇 |
2020年 | 1篇 |
2019年 | 1篇 |
2017年 | 1篇 |
2016年 | 1篇 |
2011年 | 2篇 |
2010年 | 1篇 |
2008年 | 1篇 |
2005年 | 1篇 |
2004年 | 1篇 |
2003年 | 2篇 |
1999年 | 27篇 |
1998年 | 446篇 |
1997年 | 256篇 |
1996年 | 180篇 |
1995年 | 142篇 |
1994年 | 85篇 |
1993年 | 80篇 |
1992年 | 18篇 |
1991年 | 17篇 |
1990年 | 12篇 |
1989年 | 7篇 |
1988年 | 10篇 |
1987年 | 8篇 |
1986年 | 6篇 |
1985年 | 8篇 |
1983年 | 5篇 |
1982年 | 5篇 |
1981年 | 11篇 |
1980年 | 19篇 |
1978年 | 7篇 |
1977年 | 56篇 |
1976年 | 100篇 |
1975年 | 1篇 |
排序方式: 共有1519条查询结果,搜索用时 15 毫秒
21.
22.
23.
AV Kishtovich 《Canadian Metallurgical Quarterly》1998,84(9):869-873
Depressing neurogenic and humoral (acetylcholine, papaverine and histamine) effects against the background of dilatation of arterial vessels were shown to exert different results: the former stimuli led to blood output from the veins, whereas humoral stimuli enhanced the depot role of the veins in animals. The smallest possible doses of acetylcholine did sometimes reduce the vessels' capacity. 相似文献
24.
25.
26.
AV Pisarchik G Ermak EP Demidchik LS Mikhalevich NA Kartel J Figge 《Canadian Metallurgical Quarterly》1998,8(11):1003-1008
Many neurosurgeons prefer to use intraoperative computed tomographic (CT) scanning, when possible, to check whether there is residual lesion or unexpected bleeding. We report a practical intraoperative CT imaging system using a high-speed CT scanner installed in the operating room along with a digitally controlled neurosurgical operating table. We designed a rail-track system to mobilize the CT gantry. The gantry is fixed onto a motorized carrier that can be moved smoothly on a rail-track embedded in the floor and with a maximum reach of 2.85 m from the room's wall to the operating table. The longitudinal motion of the operating table is easily adjusted by a foot switch from manual control to automatic control directly from the CT scanner's computer like an ordinary CT scanner bed in increments of 2, 5 or 10 mm during CT scanning. Either a carbon-made radiolucent head frame or carbon-made head plate is used as a headrest. Using this CT scanner system, pre- and intraoperative CT scannings were performed on 46 patients with brain tumors, cervical lesions or other intracranial lesions. We could operate on the patient with enough working space between the mobile CT gantry and the operating table for microneurosurgery. We could obtain intraoperative CT imaging of a patient on the operating table while the surgical wound remained open, the surgical drapes kept in place, and the surgical position unchanged, saving time in intraoperative CT scanning and preparation for further surgery when needed. This intraoperative CT imaging system installed in the operating room should be useful for neurosurgery. 相似文献
27.
28.
The gene rafY from the plasmid pRSD2, which enables Escherichia coli to grow on raffinose, was transferred into expression plasmid pUSL77. The protein was expressed in the porin-deficient Escherichia coli strain KS26 and was isolated and purified to homogeneity. The pure protein was reconstituted into lipid bilayer membranes. It formed an ion-permeable channel with a single-channel conductance of 2.9 nS of the open state in 1 M KCl, which is approximately twice of that of the general diffusion pores OmpF and OmpC of E. coli outer membrane. At lower pH the channel exhibited rapid flickering between three substates of the open channel. The RafY channel appears to be wide and water filled and has a small selectivity for cations over anions. Although RafY is part of an uptake and fermentation system for raffinose it does not contain a binding site for carbohydrates. Our results suggest that RafY is a general diffusion pore with a diameter, larger than that of the general diffusion porins OmpF and OmpC, that allows the diffusion of high-molecular-mass carbohydrates through the outer membrane. 相似文献
29.
AV Susekov MG Tvorogova GG Arabidze VV Kukharchuk 《Canadian Metallurgical Quarterly》1998,70(9):57-61
AIM: The study of the hypolipidemic efficiency, safety and tolerance of ciprofibrate (lipanor) in therapy of atherogenic hyperlipoproteinemia. MATERIALS AND METHODS: The trial included 14 hypertensive postmenopausal females, 14 patients with diabetes mellitus type II, 14 males with coronary heart disease and primary hyperlipoproteinemia (total cholesterol > 6.5 mmol/l, triglycerides < 4.5 mmol/l under low-cholesterol diet). Lipanor was given for 12 weeks in a daily single dose 100 mg in the morning. Lipids and other biochemical indices were measured in a fasting state after 1 and 3 months of lipanor treatment. RESULTS: After 1 month of lipanor treatment there was a 22-30%, 24-49% decrease in the level of low-density lipoprotein cholesterol, triglycerides, respectively. High-density lipoprotein cholesterol increased by 16%. The hypolipidemic effect of lipanor persisted for 3 months during which triglycerides continued to fall (up to 38.5%). Lipanor was well tolerated, only one patient with diabetes mellitus had hyperactivity of creatine phosphokinase manifesting with clinical symptoms (the drug was discontinued). 3 patients developed mild side effects. Alkaline phosphatase activity inhibited in all the groups by 25-41%. CONCLUSION: Lipanor is a highly effective, safe hypolipidemic drug with good tolerance. It can be recommended for correction of atherogenic hyperlipoproteinemia in patients at high risk of atherosclerosis progression. 相似文献
30.
In this study the interaction of applied N with different irrigation schedules on grain yields and N use efficiency of wheat was investigated in two Inceptisols of the Nigerian savanna during 1978–80. Irrigation intervals ranged from 7 to 28 days at Kadawa and 5 to 10 days at Bakura while the N rates varied from 0 to 200 kg per ha. Both grain yield and N uptake increased significantly with increasing N rates at both the locations. The magnitude of increase in yield and N uptake decreased substantially when the irrigation interval became longer. This interaction was very pronounced at Bakura where the soil is highly porous, excessively drained and extremely poor in moisture retention capacity. Longer irrigation intervals produced grains with slightly higher N content but the difference was not significant. Higher N rates and fewer irrigations gave lower fertilizer N recovery. 相似文献