全文获取类型
收费全文 | 462篇 |
免费 | 0篇 |
专业分类
化学工业 | 5篇 |
金属工艺 | 1篇 |
建筑科学 | 1篇 |
石油天然气 | 3篇 |
无线电 | 1篇 |
冶金工业 | 451篇 |
出版年
2018年 | 1篇 |
2014年 | 1篇 |
2012年 | 1篇 |
2009年 | 1篇 |
2006年 | 1篇 |
2003年 | 2篇 |
1999年 | 10篇 |
1998年 | 133篇 |
1997年 | 85篇 |
1996年 | 53篇 |
1995年 | 25篇 |
1994年 | 23篇 |
1993年 | 32篇 |
1992年 | 1篇 |
1991年 | 3篇 |
1990年 | 3篇 |
1989年 | 3篇 |
1988年 | 2篇 |
1987年 | 1篇 |
1986年 | 2篇 |
1985年 | 3篇 |
1982年 | 3篇 |
1981年 | 3篇 |
1980年 | 6篇 |
1978年 | 2篇 |
1977年 | 26篇 |
1976年 | 33篇 |
1975年 | 1篇 |
1970年 | 1篇 |
1965年 | 1篇 |
排序方式: 共有462条查询结果,搜索用时 250 毫秒
361.
H Poirel V Lacronique M Mauchauffé M Le Coniat E Raffoux MT Daniel P Erickson H Drabkin RA MacLeod HG Drexler J Ghysdael R Berger OA Bernard 《Canadian Metallurgical Quarterly》1998,16(22):2895-2903
Chromosomal translocations involving the human 12p13 band frequently affect the TEL gene, usually resulting in gene fusion between TEL and genes encoding proteins of various types. The most frequent 12p13 translocation is the t(12;21)(p13;q22), which recombines TEL with the AML1 gene on chromosome 21 and is frequently associated with deletion of the untranslocated TEL allele. Using antisera against different parts of TEL and against the AML1 proteins, we undertook Western blot and immunofluorescence analyses of leukemic samples with and without 12p13 abnormalities. In t(12;21) samples, TEL-AML1 was detected as several protein species in the nuclei, whereas the AML1-TEL protein, was inconsistently expressed. AML1 was found to be expressed but no normal TEL proteins were detected. A survey of the TEL proteins in a panel of human leukemic samples without t(12;21) revealed a variation in the ratio of TEL protein isoforms. We also analysed a leukemic cell line bearing a t(12;22)(p13;q11) that was found to affect the 5' untranslated (UT) region of TEL and to be associated with inactivation of the untranslocated TEL allele. No MN1-TEL fusion could be detected upon RT-PCR analysis, in contrast to the previously investigated t(12;22). Strikingly, extremely low levels of apparently normal TEL proteins, expressed from the translocated allele, were detected by Western blot analysis. These results suggest that the level of TEL expression can be important for leukemogenesis. 相似文献
362.
OA Dyndar 《Canadian Metallurgical Quarterly》1998,(6):102-104
Overall sixty puerperants were examined with a history of viral hepatitis before true pregnancy has set in, with 50 healthy puerperants being controls. In women with prior viral hepatitis, the B-cell link of immunity was found out to be disordered, especially so postpartum, as evidenced by investigations designed to study the chief classes of immunoglobulin G, A, M in parturient women's blood sera and the postpartum complications patterns. 相似文献
363.
IS Gribbestad TE Singstad G Nilsen HE Fj?sne T Engan OA Haugen PA Rinck 《Canadian Metallurgical Quarterly》1998,8(6):1191-1197
OBJECTIVE: To characterize sleep patterns of patients with juvenile rheumatoid arthritis (JRA). METHODS: Sixteen patients with JRA aged 12+/-4 years and 9 controls aged 11+/-3 years underwent a comprehensive evaluation by self-report questionnaire and formal all night polysomnographic recordings. Multiple sleep latency test was performed in 7 patients. RESULTS: Patients had 90% more arousals and awakenings (p<0.01) and the median length of occurrences of uninterrupted sleep in stages 2 and 3 and rapid eye movement (REM) sleep was 60% shorter than in controls (p<0.01). The overall amount of sleep stage shift from deeper to lighter sleep was 23.5+/-10.8 events in patients compared to 14.9+/-4.0 in controls (p<0.05). In 15 of 16 patients 15% of non-REM sleep consisted of alpha-delta (alpha-rating) sleep, compared with less than 1% in controls (p<0.001). Multiple sleep latency test for patients was 10.3+/-2.6 min. There were no differences between JRA and controls in self-reported questions. However, patients reported longer afternoon naps, 1.8+/-1.3 h compared to 0.3+/-0.8 h in controls (p<0.05). CONCLUSION: Objective polysomnographic evidence of abnormal sleep has been confirmed in patients with JRA. Sleep disturbance was associated with daytime sleepiness as evidenced by abnormal multiple sleep latency test and longer afternoon naptime. 相似文献
364.
We have reviewed our delivery of highly sophisticated medical therapy, haemodialysis and renal transplantation in a Caribbean setting. The purpose has been to reflect local outcomes in relation to mortality and survival, but comparisons with a vastly larger database have been attempted. Such comparisons are extremely difficult due to methodological differences and the fact that facilities contributing to that database vary considerably with regard to patient age, gender, ethnicity and comorbidity. Nonetheless, the crude data available provide important justification for the existence of regular haemodialysis and its adjunctive therapy of renal transplantation in the Caribbean. 相似文献
365.
366.
OM Laudanno JA Cesolari J Esnarriaga P Flaherty J Vada G Guastalli P San Miguel OA Bedini 《Canadian Metallurgical Quarterly》1998,28(3):249-255
BACKGROUND: General anaesthesia affects lung volume and pulmonary gas exchange. What role is played by mechanical stimulation by the endotracheal tube? METHODS: We investigated the effects of intubation on arterial oxygenation and lung volume in rats. RESULTS: Endotracheal intubation caused an increase in PA-aO2 and volume of trapped gas in the lung. This was accompanied by a reduction in neuropeptides and calcitonin gene-related peptide (CGRP) in trachea, bronchi and lung, and in vasoactive intestinal peptide (VIP) in the trachea. The increase in PA-aO2 and volume of trapped gas due to intubation was not altered in the animals given capsaicin, in which neuropeptide levels were reduced. CONCLUSIONS: These data suggest that the decrease in CGRP and VIP content in the airway tissues may be one of the consequences, but not the cause, of impaired gas exchange by endotracheal intubation. The increase in volume of trapped gas in the lung is apparently not mediated by activation of capsaicin-sensitive sensory nerves. 相似文献
367.
OA Ilahi 《Canadian Metallurgical Quarterly》1998,27(8):576-578
The combination of an anterior shoulder dislocation and an avulsion fracture of the greater tuberosity can usually be reduced by closed methods. This report describes a patient requiring open reduction and division of the subscapularis tendon before reduction of the glenohumeral dislocation could be achieved. 相似文献
368.
369.
AL Kalinin SV Zhavoronok MI Mikha?lov OG Shilenok IL Pavlovich OA Grimbaum ML Dotsenko SS Pan''ko OV Slobodina VM Bud''ko NI Stepanenko 《Canadian Metallurgical Quarterly》1998,70(6):74-77
26,740 blood donors and persons of high risk groups with respect to HBV infection, residing in different regions of Belarus, were examined for the presence of HBsAg in 1983-1997. Of these, 1372 persons (5.1%) were found to have HBsAg, and out of 1081 HBsAg-positive persons anti-HDV antibodies (Ab) were detected in 96 persons (8.9%). In spite of a decrease in acute virus hepatitis B morbidity and in HBsAg carriership, the occurrence of anti-HBV Ab remained stable during the period of 16 years and was equal, on the average, about 4% among asymptomatic HBsAg carriers. Patients having tuberculosis, rheumatoid arthritis, diabetes mellitus, hematological diseases, chronic hepatitides and cirrhosis of the liver were an important reservoir of HBV and HDV infections for regions with the low level of the spread of HBV. A decrease in the detection rate of anti-HDV Ab in patients with cirrhosis of the liver from 47.6% to 15.4% was noted. In 1991-1997 a decrease in the detection rate of anti-HDV Ab in patients with chronic hepatic lesions in comparison with 1983-1990 was observed, and in the age group older than 50 years this decrease was from 33.3% to 8.3%. This difference was particularly pronounces in patients with cirrhosis of the liver: 53.9% and 7.7% respectively. 相似文献
370.
BD Schlag JR Vondrasek M Munir A Kalandadze OA Zelenaia JD Rothstein MB Robinson 《Canadian Metallurgical Quarterly》1998,53(3):355-369
Sodium-dependent transport into astrocytes is critical for maintaining the extracellular concentrations of glutamate below toxic levels in the central nervous system. In this study, the expression of the glial glutamate transporters GLT-1 and GLAST was studied in primary cultures derived from cortical tissue. In primary astrocytes, GLAST protein levels were approximately one half of those observed in cortical tissue, but GLT-1 protein was present at very low levels compared with cortical tissue. Maintenance of these astrocytes in medium supplemented with dibutyryl-cAMP (dbcAMP) caused a dramatic change in cell morphology, increased GLT-1 and GLAST mRNA levels approximately 5-fold, increased GLAST protein approximately 2-fold, and increased GLT-1 protein >/=8-20-fold. These increases in protein expression were accompanied by 2-fold increases in the Vmax and Km values for Na+-dependent L-[3H]glutamate transport activity. Although GLT-1 is sensitive to inhibition by dihydrokainate in heterologous expression systems, no dihydrokainate sensitivity was observed in astrocyte cultures that expressed GLT-1. Biotinylation with a membrane-impermeant reagent, separation of the biotinylated/cell surface proteins, and subsequent Western blotting demonstrated that both GLT-1 and GLAST were present at the cell surface. Coculturing of astrocytes with neurons also induced expression of GLT-1, which colocalized with the glial specific marker, glial fibrillary acidic protein. Neurons induced a small increase in GLAST protein. Several studies were performed to examine the mechanism by which neurons regulate expression of the glial transporters. Three different protein kinase A (PKA) antagonists did not block the effect of neurons on glial expression of GLT-1 protein, but the addition of dbcAMP to mixed cultures of neurons and astrocytes did not cause GLT-1 protein to increase further. This suggests that neurons do not regulate GLT-1 by activation of PKA but that neurons and dbcAMP regulate GLT-1 protein through convergent pathways. As was observed with GLT-1, the increases in GLAST protein observed in cocultures were not blocked by PKA antagonists, but unlike GLT-1, the addition of dbcAMP to mixed cultures of neurons and astrocytes caused GLAST protein to increase approximately 2-fold. Neurons separated from astrocytes with a semipermeable membrane increased GLT-1 protein, indicating that the effect of neurons was mediated by a diffusible molecule. Treatment of cocultures with high concentrations of either N-methyl-D-aspartate or glutamate killed the neurons, caused GLT-1 protein to decrease, and caused GLAST protein to increase. These studies suggest that GLT-1 and GLAST protein are regulated independently in astrocyte cultures and that a diffusible molecule secreted by neurons induces expression of GLT-1 in astrocytes. 相似文献