全文获取类型
收费全文 | 582篇 |
免费 | 0篇 |
专业分类
化学工业 | 4篇 |
一般工业技术 | 1篇 |
冶金工业 | 575篇 |
自动化技术 | 2篇 |
出版年
2021年 | 1篇 |
2014年 | 1篇 |
2003年 | 1篇 |
1999年 | 15篇 |
1998年 | 154篇 |
1997年 | 99篇 |
1996年 | 56篇 |
1995年 | 45篇 |
1994年 | 27篇 |
1993年 | 34篇 |
1992年 | 6篇 |
1991年 | 5篇 |
1990年 | 5篇 |
1989年 | 10篇 |
1988年 | 9篇 |
1987年 | 6篇 |
1986年 | 7篇 |
1985年 | 11篇 |
1983年 | 2篇 |
1982年 | 2篇 |
1981年 | 6篇 |
1980年 | 9篇 |
1978年 | 1篇 |
1977年 | 21篇 |
1976年 | 47篇 |
1975年 | 1篇 |
1955年 | 1篇 |
排序方式: 共有582条查询结果,搜索用时 15 毫秒
71.
72.
Exposure to radiation results in an increased occurrence of nodularity to the thyroid and, more important, the development of cancer in a significant proportion of patients. Near-total thyroidectomy is recommended in those patients with a history of irradiation who are found on physical examination of the thyroid to have one or more nodules. Although pregnancy appears to have no effect on the course of thyroid carcinoma and the tumor has no effect on pregnancy, because of the numerous stimuli to thyroid growth during pregnancy, we feel that pregnancy is best avoided by women with known residual disease. 相似文献
73.
74.
75.
76.
77.
78.
J Ya MW Markman GT Wagenaar PJ Blommaart AF Moorman WH Lamers 《Canadian Metallurgical Quarterly》1997,249(4):495-505
Tip growth of plant cells has been suggested to be regulated by a tip-focused gradient in cytosolic calcium concentration ([Ca2+]c). However, whether this gradient orients apical growth or follows the driving force for this process remains unknown. Using localized photoactivation of the caged calcium ionophore Br-A23187 we have been able to artificially generate an asymmetrical calcium influx across the root hair tip. This led to a change in the direction of tip growth towards the high point of the new [Ca2+]c gradient. Such reorientation of growth was transient and there was a return to the original direction within 15 min. Root hairs forced to change the direction of their growth by placing a mechanical obstacle in their path stopped, reoriented growth to the side, and grew past the mechanical blockage. However, as soon as the growing tip had cleared the obstacle, growth returned to the original direction. Confocal ratio imaging revealed that a tip-focused [Ca2+]c gradient was always centered at the site of active growth. When the root hair changed direction the gradient also reoriented, and when growth returned to the original direction, so did the [Ca2+]c gradient. This normal direction of apical growth of Arabidopsis thaliana (L.) Heynh, root hairs was found to be at a fixed angle from the root of 85 +/- 6.7 degrees. In contrast, Tradescantia virginiana (L.) pollen tubes that were induced to reorient by touch or localized activation of the caged ionophore, did not return to the original growth direction, but continued to elongate in their new orientation. These results suggest that the tip-focused [Ca2+]c gradient is an important factor in localizing growth of the elongating root hair and pollen tube to the apex. However, it is not the primary determinant of the direction of elongation in root hairs, suggesting that other information from the root is acting to continuously reset the growth direction away from the root surface. 相似文献
79.
Three patients, one healthy and two immunocompromised, developed cutaneous reactions that histologically mimicked granuloma annulare at sites of resolved varicella-zoster virus (VZV) reactivation infections. Variable latency periods between the infection and the granulomatous reaction were noted. As in other case reports, the presence of VZV DNA in these lesions was inconsistently demonstrated by the polymerase chain reaction (PCR) and appears more common in early, as opposed to late, post-zoster granulomas. In addition to various granulomatous reactions, vasculitic and neoplastic eruptions following resolved VZV infections have been described and are reviewed here. Therapeutically, topical, intralesional and systemic corticosteroids, as well as acyclovir, have been tried with inconsistent results. Although the pathogenesis remains unclear, the presence of VZV DNA in early lesions that histologically do not display viral cytopathic changes, suggests the virus induces an atypical delayed hypersensitivity reaction not affected by antiviral therapy. 相似文献
80.
Personnel at the general intensive care unit at the University of Heidelberg Children's Hospital aim for a maximum of openness and transparency for parents regarding everything relevant to their own child. In this context ward nurses were interviewed about diverse aspects of their work. Aside from technical-medical activities, nurses regarded the relationship to the parents to be a central point in their work. The recognize that the relationship to the parents influences the relationship to the child and partially even the nursing of the child. Nurses are in favor of openness and transparency in relating to parents, however, reality reveals contradictions. Nurses differentiated attitude and the consequences for physicians, psychologists and parents are discussed. A case example is presented. 相似文献