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91.
92.
OBJECTIVE: In rodents, leptin is involved in regulating eating behaviour, fat storage, and reproductive function. In humans, the serum leptin concentration in obese and normal weight subjects correlates with body mass index, reflecting the body fat store. The serum leptin exhibit diurnal variation, however, this has been reported to be absent in normal weighted amenorrheic athletes. Anorexia nervosa is associated with multiple endocrine abnormalities. Hypothalamic amenorrhoea often precedes the weight loss and may persist after weight recovery. We hypothesized that leptin could be involved in the regulation of eating behaviour and gonadal function in anorexia nervosa. DESIGN: We measured the concentration of leptin in serum samples taken after an overnight fast in 18 female anorexia nervosa patients and 11 controls. To study diurnal variation, eight patients and 11 controls were hospitalized for 24 h and had a standardized diet at regular times. Seven blood samples were obtained at 4 h intervals from each subject. PATIENTS: The patients fulfilled the DSM-IV criteria for anorexia nervosa. The mean body mass index for the patients was 14.2 +/- 2.3 kg/m2 and for controls 20.3 +/- 1.7 kg/m2. RESULTS: The mean fasting leptin concentration as well as the 24 h mean concentration were significantly lower in the anorectic group than in the control group (2.5 +/- 0.9 vs 10.1 +/- 6.1 micrograms/l, P < 0.01 and 2.7 +/- 1.5 vs 10.6 +/- 7.1 micrograms/l, P < 0.01 respectively). In the whole group of subjects (n = 28) a significant positive correlation between the leptin level and body mass index was found (r = 0.63, P < 0.001). In the anorectic group it was found that the leptin level correlated better with body fat percentage than with body mass index. In normalized data the time course of the mean leptin levels showed a monophasic variation with nadir and zenith at about 0900 and 0100 h respectively. However, the individual coefficients of variance were significantly lower in the anorectic group compared to the group of healthy women. CONCLUSION: In patients with anorexia nervosa the leptin level is low, reflecting the low body fat mass, and the relative diurnal variation is strikingly reduced. The similarity to that of normal weighted women with hypothalamic amenorrhoea suggest that altered leptin oscillations may be of particular significance in the hypothalamic regulation of reproductive function.  相似文献   
93.
We have recently demonstrated that a single injection of 4,900 IU of interleukin-12 (IL-12) on the day of bone marrow transplantation (BMT) markedly inhibits acute graft-versus-host disease (GVHD) in a fully major histocompatibility complex plus minor antigen-mismatched BMT model (A/J --> B10, H-2(a) --> H-2(b)), in which donor CD4(+) T cells are required for the induction of acute GVHD. We show here that donor CD8-dependent graft-versus-leukemia (GVL) effects against EL4 (H-2(b)) leukemia/lymphoma can be preserved while GVHD is inhibited by IL-12 in this model. In mice in which IL-12 mediated a significant protective effect against GVHD, marked GVL effects of allogeneic T cells against EL4 were observed. GVL effects against EL4 depended on CD8-mediated alloreactivity, protection was not observed in recipients of either syngeneic (B10) or CD8-depleted allogeneic spleen cells. Furthermore, we analyzed IL-12-treated recipients of EL4 and A/J spleen cells which survived for more than 100 days. No EL4 cells were detected in these mice by flow cytometry, tissue culture, adoptive transfer, necropsies, or histologic examination. Both GVL effects and the inhibitory effect of IL-12 on GVHD were diminished by neutralizing anti-interferon-gamma (IFN-gamma) monoclonal antibody. This study demonstrates that IL-12-induced IFN-gamma production plays a role in the protective effect of IL-12 against GVHD. Furthermore, IFN-gamma is involved in the GVL effect against EL4 leukemia, demonstrating that protection from CD4-mediated GVHD and CD8-dependent anti-leukemic activity can be provided by a single cytokine, IFN-gamma. These observations may provide the basis for a new approach to inhibiting GVHD while preserving GVL effects of alloreactivity.  相似文献   
94.
ZF Xiu  YG Song 《Canadian Metallurgical Quarterly》1994,33(4):406-9; discussion 409-11
On the basis of our years of clinical experience using the "unequal bite" suturing technique to perform end-to-end anastomosis of vessel with great discrepancy in diameter, an animal experimental study was performed in which an arterial defect, 1.0 to 1.4 mm in diameter, was reunited through the autogenous arterial graft, which was 0.3 to 0.4 mm in diameter. A high patency rate (95% in total) was obtained postoperatively. A small autogenous arterial graft may be used for repairing a large-caliber arterial defect clinically.  相似文献   
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96.
Stimulation of macrophages with colony-stimulating factor-1 (CSF-1) results in the protein tyrosine phosphorylation of the CSF-1 receptor (CSF-1R) and many other, primarily cytosolic, proteins. Stimulation by CSF-1 at 4 degreesC was used to facilitate the purification and identification of the proteins of the cytosolic anti-phosphotyrosine (PY)-reactive fraction (alphaPY-RF) involved in downstream signaling pathways. Confocal microscopy revealed that the PY proteins are in close proximity to the CSF-1R at the plasma membrane. The alphaPY-RF contained pre-existing complexes of PY proteins and non-PY proteins which generally increased in size and PY protein content following CSF-1 stimulation. PY proteins identified by microsequencing and Western blotting include Cbl, STAT3, STAT5a, STAT5b, SHP-1, Shc, and two novel proteins pp57 and pp37. Other proteins included cytoskeletal/contractile proteins (paxillin, vimentin, elongation factor-1alpha, F-actin, tropomyosin, and myosin regulatory light chain), Ras family signaling proteins (p85 (phosphoinositide 3-kinase), Vav, Ras-GTPase-activating protein SH3 domain-binding protein, and Grb2), DnaJ-like protein, and glyceraldehyde-3-phosphate dehydrogenase. CSF-1 induced the de novo recruitment of Cbl, STAT3, STAT5a, STAT5b, p85, SHP-1, Shc, vimentin, and Grb2 to complexes and caused pre-existing complexes involving Vav, elongation factor-1alpha, and F-actin to increase in size. These studies indicate that CSF-1-induced protein tyrosine phosphorylation is associated with the reorganization of complexes of cytoskeletal, signaling, and other proteins that mediate CSF-1-regulated motility and growth.  相似文献   
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98.
1. The amnesia induced by various stress stimuli through hypoxia and cerebral ischemia was evaluated by the shortening of the response latency in a step-through task in mice. 2. The hypoxia-induced amnesia was reduced by cromakalim, a K+ channel opener (KCO), given 10 min before or immediately after the hypoxic treatment. 3. Similarly, the ischemia-induced amnesia was also reduced by cromakalim given 30 min before the occlusion. 4. In ischemic-induced amnesic mice, pyknotic cells, indicating the condensation of chromatin, were observed histochemically at the dentate gyrus granule cells in hippocampal regions 96 hr after ischemic treatment. In addition, cromakalim inhibited the induction of pyknotic cells. 5. These results suggest that KCOs might produce prophylactically neuroprotective effects against hypoxia- and cerebral ischemia-induced amnesia.  相似文献   
99.
The effects of denervated muscle and Schwann cells on collateral sprouting from peripheral nerve were studied in the peroneal and tibial nerves of 48 Sprague-Dawley rats. Three groups were prepared. In group MSW (muscle-Schwann cell-window), the peroneal nerves were transected 3 mm below the sciatic bifurcation. The proximal stumps were sealed in a blocked tube to prevent regeneration and the distal stumps were implanted into denervated muscle cells that were wrapped around the ipsilateral tibial nerve, which had a window of perineurium resected. Schwann cells from the ipsilateral sural nerve were implanted into the muscle. Group MS (muscle-Schwann cell) was similar to group MSW, except that the tibial nerve perineurium was kept intact. In group MW (muscle-window), the muscle was prepared without Schwann cells and the tibial nerve perineurium was windowed. S-100 immunostain was used to identify the Schwann cells surviving 1 week after transplantation. After 16 weeks of regeneration, horseradish peroxidase tracer was used to label motor neurons and sensory neurons reinnervating the peroneal nerve. Myelinated axons of the reinnervated peroneal nerves were quantified with the Bioquant OS/2 computer system (R&M Biometrics, Nashville, TN). A mean of 169 motor neurons in group MSW, 64 in group MW, and 26 in group MS reinnervated the peroneal nerve. In the dorsal root ganglion, the mean number of labeled sensory neurons was 1,283 in group MSW, 947 in group MS, and 615 in group MW. The mean number of myelinated axons in the reinnervated peroneal nerve was 1,659 in group MSW, 359 in group MS, and 348 in group MW. Reinnervated anterolateral compartment muscles in group MSW were significantly heavier than those in group MS or MW. This study demonstrates that the transplantation of denervated muscle and Schwann cells promotes motor and sensory nerve collateral sprouting through a perineurial window.  相似文献   
100.
Anti-tumor activity of antizyme which targets the ornithine decarboxylase (ODC) required for cell growth and transformation Cell proliferation and transformation induced by growth factor stimulation or by carcinogens, viruses, or oncogenes are characterized by an associated increase in polyamine levels, which is mediated by increased polyamine biosynthesis and enhanced uptake of polyamines. Polyamine biosynthesis is catalyzed particularly, in the level of ornithine decarboxylase (ODC). The elevation of cellular polyamine levels on the other hand accelerates the induction of ornithine decarboxylase antizyme (antizyme), which is involved not only in ODC-degradation, but in the negative regulation of polyamine transport. Taking advantage of these characteristics of antizyme, the potential of antizyme as a factor having anti-cell growth and anti-tumor activity was investigated. We show that antizyme can induce cell death associated with a rapid decline of intracellular polyamine contents. The possible anti-tumor activities of ectopically expressed antizyme were tested in p21H-ras (Val 12)-transformed NIH3T3 cells and several human malignant cell lines including a line with loss of p53 expression, and they were shown to be as sensitive as nontransformed NIH3T3 cells in vitro. The in vivo anti-tumor activity was also tested using nude mice inoculated with H-ras transformed NIH3T3 cells that had been transfected with inducible antizyme expression vector and the results showed that antizyme expression in vivo blocks tumor formation in these mice. These results suggest that ectopic antizyme expression is of possible therapeutic benefit in the treatment of cancer, which is mediated by ODC inactivation and intracellular polyamine depletion.  相似文献   
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