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81.
Multiple episodes of blood-brain barrier disruption were induced by sequential intraspinal injections of ethidium bromide. In addition to the barrier disruption, there was toxic demyelination and exposure of myelin components to the immune system. Twenty-seven 3-month-old Wistar rats received 2, 3 or 4 injections of 1 microliter of either 0.1% ethidium bromide in normal saline (19 rats) or 0.9% saline (8 rats) at different levels of the spinal cord. The time intervals between the injections ranged from 28 to 42 days. Ten days after the last injection, all rats were perfused with 2.5% glutaraldehyde. The spinal sections were evaluated macroscopically and by light and transmission electron microscopy. All the lesions demonstrated a mononuclear phagocytic infiltrate apparently removing myelin. Lymphocytes were not conspicuous and were found in only 34% of the lesions. No perivascular cuffings were detected. In older lesions (38 days and older) they were found only within Virchow-Robin spaces. This result suggests that multiple blood-brain barrier disruptions with demyelination and exposure of myelin components to the immune system were not sufficient to induce an immune-mediated reaction in the central nervous system. 相似文献
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83.
The Salmonella strains described in this paper were isolated from clinical and environmental sources in Togo (West Africa). All strains belong to subgenus I of the genus Salmonella. 1. Salmonella kodjovi 47:c:-, Supplement No. XVII (1974), isolated from stool specimen 2. Salmonella dadzie 51:1, v:e, n, x, Supplement No. XVII (1974), isolated from stool specimen 3. Salmonella mono 4, 12:1, w:1, 5, Supplement No. XVII (1975), isolated from pig droppings 4. Salmonella chincol var. s-, monophas. 6, 8:g, m:-, Supplement No. XVIII (1975), isolated from lizard intestines 5. Salmonella chicago var. i+, 28:r, i:1,5, Supplement No. XVIII (1975), isolated from stool specimen 6. Salmonella havana var. s+, 36+, 13,23:f,g,s:-, Supplement No. XVIII (1974), isolated from stool specimen 7. Salmonella elisabethville var. 15+, 3,15:r:1,7, isolated from lizard intestines. 相似文献
84.
Although paroxysmal kinesigenic dyskinesia (PKD) has characteristic clinical features, the pathophysiology of PKD has remained unknown. The purpose of this study was to investigate the pathophysiology of idiopathic PKD by performing proton magnetic resonance spectroscopy (1H-MRS) in five patients with idiopathic PKD. Three patients were familial and two sporadic. Single-voxel 1H-MRS was performed on a GE 1.5-T SIGNA MR system. Localized 1H-MR spectra were obtained from the basal ganglia (n = 5), thalamus (n = 3), and supplementary motor area (SMA; n = 4) using STEAM sequence (stimulated echo acquisition mode; TR = 3.0 sec, TE = 30 msec, 64 AVG, volume = 8 mL) or PRESS (point resolved spectroscopy; TR = 3.0 sec, TE = 135 msec, volume = 4 mL). Peak ratios of Cho/Cr (Cho: choline, Cr: creatine) and mI/Cr (mI: myoinositol) were decreased significantly in the unilateral basal ganglia of two patients. In one, decreased peak ratio of mI/Cr in the unilateral basal ganglia was the only abnormality. In the remaining two, there was no significant abnormality. 1H-MR spectra obtained from the thalamus and SMA were all within normal limits. In conclusion, these results suggest that underlying pathophysiological mechanism of PKD may be at least partially associated with the dysfunction of cholinergic system in the basal ganglia. 相似文献
85.
1. A new method has been used to measure pKI values of prazosin and idazoxan against neuronally-released transmitter in the epididymal portion of the rat isolated vas deferens. The most reproducible results were obtained with a prolonged antagonist equilibration time (1 h). 2. Under these conditions the pKI of prazosin was practically unaffected by addition of alpha, beta-methylene-adenosine-5'-triphosphate (10 microM) to desensitize purinoceptors. Addition of desmethylimipramine (DMI) (0.3 microM) produced a small, but statistically non-significant, reduction. 3. The same method has been used to measure the pKI of prazosin against exogenous noradrenaline. In the latter case addition of DMI (0.3 microM) and corticosterone (30 microM) together produced a statistically significant reduction in the apparent pKI of prazosin. 4. The new method for estimating pKI values shows that DMI itself acts either pseudo-irreversibly or non-competitively and may be reducing the apparent pKI of prazosin. 5. The pKI values obtained for prazosin and idazoxan against neuronally-released transmitter are in good agreement with those obtained by other workers for the actions of these drugs on alpha-adrenoceptors. 相似文献
86.
Western blot analysis was carried out using crude antigens of Echinococcus multilocularis and 33 serum samples from the People's Republic of China to differentiate patients with alveolar hydatid disease (AHD) with active lesions from those with inactive lesions, those with other parasitoses including cystic hydatid disease (CHD), and healthy persons. This analysis was based on the detection of antibody responses against two polypeptides, Em18 and Em16, which appeared to be species specific and good indices for the differentiation of AHD with active lesions from AHD with inactive lesions. Twenty-one of the 33 samples showed antibody responses against Em18 and/or Em16. Fifteen were antibody-positive for both Em18 and Em16, five were antibody-positive for Em18 only, and one was antibody-positive for Em16 only. Of the subjects from which the 33 samples were obtained, 12 patients had AHD with active lesions, two had AHD, but their lesions were resolved by surgical resections, 14 had CHD with active lesions, and five were apparently healthy people. Western blot analysis confirmed all 14 cases of AHD, three of the 14 cases of CHD, and showed that one of the five apparently healthy individuals had a positive serologic response for AHD. This apparently healthy person with a positive serologic response for AHD by Western blot analysis was found to be positive for the disease on re-examination. Thus, Western blot analysis based on the antibody responses against Em18 and Em16, especially against Em18, was extremely reliable for the detection of AHD with active lesions, although it failed to differentiate two of the 14 patients with CHD.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
87.
A case of permanent atrial standstill is described in a 10-month-old dog with ascites as a presenting complaint. The patient had absence of P waves in all leads in numerous ECG's and had a regular idioventricular rhythm. Pathologically, the patient had multiple areas of atrial and ventricular myocardial necrosis and fibrosis, with chronic active myocarditis and obliteration of the SA and AV node and AV bundle. 相似文献
88.
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90.
Comparison of orthorhombic and alpha-two titanium aluminides as matrices for continuous SiC-reinforced composites 总被引:1,自引:0,他引:1
P. R. Smith J. A. Graves CG. Rhodes 《Metallurgical and Materials Transactions A》1994,25(6):1267-1283
The attributes of an orthorhombic Ti aluminide alloy, Ti-21Al-22Nb (at. pct), and an alpha-two Ti aluminide alloy, Ti-24Al-11Nb
(at. pct), for use as a matrix with continuous SiC (SCS-6) fiber reinforcement have been compared. Foil-fiber-foil processing
was used to produce both unreinforced (“neat”) and unidirectional “SCS-6” reinforced panels. Microstructure of the Ti-24A1-11Nb
matrix consisted of ordered Ti3Al (α
2) + disordered beta(β), while the Ti-21 Al-22Nb matrix contained three phases: α2, ordered beta (β
0), and ordered orthorhombic(O). Fiber/ matrix interface reaction zone growth kinetics at 982 °C were examined for each composite system. Although both systems
exhibited similar interface reaction products(i.e., mixed Ti carbides, silicides, and Ti-Al carbides), growth kinetics in theα
2 +β matrix composite were much more rapid than in theO +β
0 +α
2 matrix composite. Additionally, interfacial reaction in theα
2 +β} composite resulted in a relatively large brittle matrix zone, depleted of beta phase, which was not present in theO +β
0+α
2 matrix composite. Mechanical property measurements included room and elevated temperature tensile, thermal stability, thermal
fatigue, thermo-mechanical fatigue (TMF), and creep. The three-phase orthorhombic-based alloy outperformed the α2+β alloy in all of these mechanical behavioral areas, on both an absolute and a specific(i.e., density corrected) basis. 相似文献