全文获取类型
收费全文 | 4541篇 |
免费 | 1篇 |
专业分类
电工技术 | 7篇 |
综合类 | 1篇 |
化学工业 | 17篇 |
建筑科学 | 6篇 |
轻工业 | 3篇 |
水利工程 | 1篇 |
无线电 | 3篇 |
一般工业技术 | 10篇 |
冶金工业 | 4480篇 |
自动化技术 | 14篇 |
出版年
2022年 | 2篇 |
2021年 | 1篇 |
2019年 | 1篇 |
2014年 | 6篇 |
2013年 | 4篇 |
2012年 | 3篇 |
2011年 | 2篇 |
2009年 | 3篇 |
2006年 | 5篇 |
2004年 | 2篇 |
2003年 | 10篇 |
2000年 | 4篇 |
1999年 | 128篇 |
1998年 | 1391篇 |
1997年 | 854篇 |
1996年 | 490篇 |
1995年 | 268篇 |
1994年 | 251篇 |
1993年 | 278篇 |
1992年 | 35篇 |
1991年 | 49篇 |
1990年 | 73篇 |
1989年 | 61篇 |
1988年 | 68篇 |
1987年 | 63篇 |
1986年 | 45篇 |
1985年 | 36篇 |
1984年 | 1篇 |
1983年 | 8篇 |
1982年 | 12篇 |
1981年 | 29篇 |
1980年 | 44篇 |
1979年 | 2篇 |
1978年 | 7篇 |
1977年 | 92篇 |
1976年 | 205篇 |
1975年 | 5篇 |
1964年 | 1篇 |
1955年 | 3篇 |
排序方式: 共有4542条查询结果,搜索用时 15 毫秒
51.
FV Elmslie AJ Vivian H Gardiner C Hall AP Mowat RM Winter 《Canadian Metallurgical Quarterly》1995,32(4):264-268
Alagille syndrome (AGS) is one of the major forms of chronic liver disease in childhood with severe morbidity and a mortality of 10 to 20%. It is characterised by cholestasis of variable severity with paucity of interlobular bile ducts and anomalies of the cardiovascular system, skeleton, eyes, and face. Previous studies suggest a wide variation in the expression of the disease and a high incidence of new mutations. To determine more accurately the rate of new mutations and to develop criteria for detecting the disorder in parents we systematically investigated parents in 14 families with an affected child. Clinical examination was supplemented by liver function tests, echocardiography, radiographic examination of the spine and forearm, ophthalmological assessment, and chromosome analysis. Six parents had typical anomalies in two or more systems pointing to the presence of autosomal dominant inheritance. Systematic screening of parents for the features defined in this study should improve the accuracy of genetic counselling. 相似文献
52.
53.
54.
AJ Dorta M Ferra R Bu-Colfiu L García M Gil X Escobar G Martín NA Díaz OM Perez MT Interián 《Canadian Metallurgical Quarterly》1993,10(10):490-491
It is essential to know how the immune system acts in different neurological diseases, some of them non very well known or of unknown etiology at all. It was applied Reiber and Felgenhauer's formula in 56 patients with different diseases. IgA, IgM, IgG and albumin were quantified in sera and cerebrospinal fluid by simple immunodiffusion. It was observed more frequent IgG local synthesis and IgA in this sample. 相似文献
55.
56.
57.
58.
59.
AJ Caraballo 《Canadian Metallurgical Quarterly》1996,30(5):483-484
An outbreak of 154 cases of vampire bat biting in a four-month period in the gold mine of Payapal, a Venezuelan village, is reported. All patients were bitten during the night and the most bites were on their toes. No complication attributed to the bite was reported. Diagnoses of rabies virus made by means of immunofluorescence were negative. A possible reason for this outbreak may been the development of mining areas, with the inhabitants providing an alternative food source for the bats. 相似文献
60.
It is important to monitor the early stages of postoperative wound repair in order to identify those problems associated with impaired healing. Many of the crucial cellular responses of early wound healing, such as inflammatory infiltration, angiogenesis and re-epithelialization, are made possible through the action of matrix metalloproteinases (MMPs). Expression of MMP-2 and MMP-9 is elevated in acute wounds, and still greater levels are found in chronic wounds, indicating that uncontrolled proteolysis is a characteristic of retarded healing. Therefore, comparative measurements of MMPs may be used to monitor the progression of early wound healing. To investigate this, wound fluids and sera were collected from mastectomy and colectomy patients throughout early stages of repair, and the temporal expression profile established. Wounds which were healing were expressed maximal levels of MMP-9 at 24 h, followed by a significant decline by 48 h. Persistent elevation of MMP-9 expression was associated with infected and chronic wounds, and was identified in postoperative wounds by the absence of the significant decline between 24 and 48 h. Measurement of MMP-9 in postoperative wound fluids, therefore, provides an early indicator of impaired healing, which may be evaluated non-invasively within 48 h of closure. 相似文献