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91.
Cardiopulmonary bypass (CPB) is known to induce several pathogenic responses in cardiovascular surgery. To explore leukocyte activation during PCB, we investigated superoxide anion (O2-) production by granulocytes in 6 patients undergoing aortocoronary bypass surgery. O2- production was determined with chemiluminescence amplified by a cypridina luciferin analogue. Granulocytes collected from the blood in the arterial site of the CPB circuit were stimulated by phorbol myristate acetate, n-formyl-methionyl-leucyl-phenylalanine, and opsonized zymosan. All the stimulators failed to disclose a significant difference between the magnitude of chemiluminescence during and after CPB. However, significant complement activation was detected, and the plasma level of granulocyte elastase increased gradually during and after CPB. This discrepancy between the unchanged O2- production by stimulated granulocytes and the increase in inflammatory mediators including granulocyte elastase may be due to sequestration of activated granulocytes in extravascular tissues. Namely, it was highly likely that activated granulocytes responsible for the increased plasma elastase level were sequestered and remained outside the blood circulation.  相似文献   
92.
Thermostable direct haemolysin of Vibrio parahaemolyticus has been shown to be a major virulence factor. The Kanagawa phenomenon (KP), haemolysis induced by this haemolysin on a special blood agar medium, is strongly associated with clinical strains. We have been studying the expressions of various tdh genes encoding this haemolysin to elucidate the significance of the tdh genes possessed by KP-negative strains isolated from patients. We examined the importance of the promoter sequence variation for expression level of the tdh gene in this study. Only the tdh2 gene, one of the two tdh genes (tdh1 and tdh2) present in a KP-positive strain, was previously shown to be responsible for the haemolytic activity of the KP-positive strain. The tdh1- and tdh2-lacZ fusions were used to determine and analyse the promoter sequence by primer extension and site-directed mutagenesis methods. Two bases (positions -24 and -34) within the determined tdh2 promoter sequence were shown to be mostly responsible for the difference in the promoter strength between the tdh2 and tdh1 genes both in Escherichia coli and in V. parahaemolyticus backgrounds. Representative tdh promoters of KP-negative strains are close to the tdh2 promoter; they differ at position -34 but have the same base at position -24 as the tdh2 promoter. We demonstrated that base substitution of the tdh promoters of KP-negative strains only at position -34 is sufficient to increase the expression of these genes to the KP-positive level. Therefore, the tdh genes of KP-negative strains are considered to be potentially important because they can generate a KP-positive subclone by a point mutation in their promoters.  相似文献   
93.
Contact-inhibited catalase-deficient fibroblast cell strain has been established from the homozygous hypocatalasemic C3H/Csb mutant mouse. This cell strain has low level of catalase enzyme activity and has normal level of enzyme activities of both glutathione peroxidase and superoxide dismutase. Catalase-deficient C3H/Csb mutant cell strain is markedly more sensitive to the toxicity of hydrogen peroxide compared to wild-type C3H/Csa cell strain. In addition, mutant cell strain is sensitive to X-rays and near-UV compared to wild-type cell strain, but shows the same sensitivities to topoisomerase II inhibitors, adriamycin and 4'-(9-acridinylamino) methanesulfon-m-anisidide (m-AMSA), and the DNA cross-linking agents, cisdiamminedichloroplatinum (II) (cis-Pt) and trans-diamminedichloroplatinum (II) (trans-Pt). These cell strains will be of use in the study of the roles which catalase plays in the intracellular prevention of DNA damage induced by oxidative stress.  相似文献   
94.
Intraspinal replantation of avulsed spinal nerve roots as a surgical treatment for motor deficits after severe brachial plexus injury was investigated in primates. Under general anaesthesia hemi-laminectomy was performed in cynomolgus monkeys (Macaca fascicularis). Ventral roots within the brachial plexus were then avulsed by traction and subsequently implanted into the ventrolateral aspect of the spinal cord. No dysfunction in the long fibre tracts was seen following surgery. Postoperatively there was a flaccid paralysis of the arm on the lesioned side. Severe atrophy developed within 5-7 weeks in the muscles supplied by the avulsed roots and EMG revealed denervation activity. Two to three months after surgery there were EMG signs of reinnervation, which were shortly followed by evidence of clinical recovery. A gradual improvement in the function of the affected arm occurred and the animals' motor behaviour normalised. One year after surgery there was a full range of motion in the arm, but the EMG activity in the reinnervated muscles at maximal force was reduced. Tracing of regenerated motor neurons with horseradish peroxidase (HRP) injected into the biceps muscle revealed retrogradely labelled motor neurons confined to the ipsilateral ventral horn. It was concluded that intraspinal replantation of avulsed ventral roots in primates significantly promotes motor recovery in the muscles supplied by the lesioned spinal cord segments.  相似文献   
95.
To develop new polymer-based materials, the design of aliphatic carbonate has received attention and become a well-known cyclic monomer. In view of carbonate ring polymer scope, poly(trimethylene carbonate) (PTMC) has been continuously developed for further applications due to its unique degradability. PTMC bearing oligo ethylene glycol units, PTMCM-MOE3OM, were typically prepared via ring-opening polymerization (ROP) using amidine-based catalysts such as 1,8-diazabicyclo[5.4.0] undec-7-ene (DBU) and benzyl alcohol (BnOH) as an initiator. To improve the polymer molecular weight or other properties, several know-how synthetic catalysts based on organometallic complexes are under consideration as potential catalysts. With the existence of diverse classes of metallic complexes, the inorganic complexes were investigated for their catalytic activity based on tris(dimethylsilyl)amido chelating, bis(phenolate) chelating, and macrocyclic tetradentate (NNNN)-type cyclen chelating with a metal-core of tin (II), scandium (III), lutetium (III), and zinc (II). In this study, we found that involving a Zn(II) dimethylcyclen/alkoxide ligand and Mg complexes could accelerate the reaction and finish the polymerization under ambient conditions within 2 hr. Molecular weight reached 11,000 g/mol (40%) and 8,100 g/mol (> 96%). Subsequently, we concluded that Zn and Mg complexes were high reactivity for initiating the ROP of TMCM-MOE3OM upon steadily degree of polymerization.  相似文献   
96.
Herein, the design, synthesis, and characterization of bifunctional hybrid nanoreactors used for concurrent one‐pot chemoenzymatic reactions are shown. In the design, the enzyme, glucose oxidase, is wrapped with a peroxidase‐mimetic catalytic polymer. Hemin, the organic catalyst, is linked to the flexible polymeric scaffold through coordination to the imidazole groups that hang out the network. This spatial arrangement, which works as a metabolic channel, is optimized for cooperative chemoenzymatic reactions in which the enzyme catalyzes first. A deep characterization of the integrated nanoreactors demonstrates that the confinement of two distinct catalytic sites in the nanospace is very effective in one‐pot reactions. Moreover, besides its role as scaffold material, the polymeric mantel protects both the biocatalyst and the chemical catalyst from degradation and inactivation in the presence of organic solvents. Furthermore, the polymeric environment of the nanoreactors can be tailored in order to trigger the assembly of those into highly active heterogeneous hybrid catalysts. Finally, the new nanoreactors are applied to the efficient degradation of organic aromatic compounds using glucose as the only fuel.  相似文献   
97.
The effects of pinacidil and nimodipine on endothelin-1-induced contractions in isolated cerebral arteries with and without endothelium were compared. The sensitivity to endothelin-1 was increased (0.5 log units) in the rabbit basilar artery after removal of the endothelium. The nitric oxide synthase inhibitor N omega-nitro-L-arginine (0.1 mM) also increased the sensitivity to endothelin-1 (0.6 log units) in basilar arteries with endothelium, whereas N omega-nitro-D-arginine (0.1 mM) and indomethacin (3 microM) had no effect, indicating that withdrawal of endothelium-derived nitric oxide may account for the enhancement of the endothelin-1-induced contraction after endothelial denudation. Pinacidil (1 microM) shifted the concentration-response curve for endothelin-1 to the right without affecting the maximal response in arteries without endothelium, but had no effect on the endothelin-1-induced contraction in vessels with endothelium. Nimodipine (1 microM) reduced the maximal endothelin-1-induced contraction by approximately 50% in both the presence and absence of endothelium, whereas the sensitivity to endothelin-1 was reduced only in vessels without endothelium. Incubation in "calcium-free" medium reduced the maximal endothelin-1-induced contraction by 69% and 80% in vessels with and without endothelium, respectively. In human pial arteries with endothelium, pinacidil did not affect the endothelin-1-induced contraction, whereas nimodipine and exposure to "calcium-free" solution reduced the maximal response by 31% and 74% respectively. The results show that, in the rabbit, pinacidil and to a lesser extent nimodipine preferentially act on cerebral arteries with disrupted endothelium, indicating that vasoactive factors liberated from the endothelium may modify the effect of a vasodilator.  相似文献   
98.
The combined flushing and oxidation process using acetic acid and ozone has been used successfully to remove trichloroethylene (TCE) completely from contaminated soil. In this study, the effects of humic acid, a fraction of the organic matter in soil, over the performance of TCE decomposition was evaluated. TCE decomposition by ozone was enhanced by the presence of humic acid at concentrations lower than 8mgCL(-1) and then inhibited at higher concentrations. It is possible that the presence of the soluble humic acid fraction during the ozonation of TCE in acetic acid solutions produces hydroxyl radicals during the TCE ozonation which appears to be the reason for the enhanced TCE decomposition rate. Solid humic acid reduced TCE decomposition rate by acting as an ozone scavenger. Similarly, sorbed TCE reduced the amount of TCE available for decomposition by ozone in solution.  相似文献   
99.
This paper describes some applications of Thermo-Calc to steel product development. Calculations of thermodynamic equilibria such as phase boundary and equilibrium precipitates have been utilized for the following R&;D items: the strengthening of thin-gage steel sheets for cans, the prevention of sensitization in stainless steels, the optimization of rolling conditions for Si steels, and the decreasing in yield ratio of interstitial-free steels.  相似文献   
100.
Lysophosphatidic acid (LPA) modulates prostaglandin (PG) synthesis via LPA receptor 3 (LPAR3) in the murine endometrium. The lack of functional LPAR3 in mice may lead to embryo mortality. In the present study, we examined the role of LPA in the bovine uterus. We confirmed that LPA is locally produced and released from the bovine endometrium. Moreover, there are enzymes involved in LPA synthesis (phospholipase (PL) D(2) and PLA2G1B) in the bovine endometrium during estrous cycle and early pregnancy. Expression of the receptor for LPA (LPAR1) was positively correlated with the expression of PGE(2) synthase (PGES) and negatively correlated with the expression of PGF(2alpha) synthase (aldose reductase with 20 alpha-hydroxysteroid dehydrogenase activity - PGFS) during early pregnancy. In vivo LPA induced P4 and PGE(2) secretion was inhibited by LPAR1 antagonist (Ki16425). The overall results indicate that LPA is locally produced and released from the bovine endometrium. Moreover, LPAR1 gene expression in the endometrium during the estrous cycle and early pregnancy indicates that LPA may play autocrine and/or paracrine roles in the bovine uterus. LPAR1 gene expression is positively correlated with the expression of the enzyme responsible for luteotropic PGE(2) production (PGES) in endometrium. In cow, LPA stimulates P4 and PGE(2) secretion. Thus, LPA in the bovine reproductive tract may indirectly (via endometrium) or directly support corpus luteum action via the increase of P4 synthesis and the increase of PGE(2)/PGF(2)(alpha) ratio. It suggests that LPA may serve as an important factor in the maintenance of early pregnancy in cow.  相似文献   
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