全文获取类型
收费全文 | 6563篇 |
免费 | 44篇 |
国内免费 | 2篇 |
专业分类
电工技术 | 28篇 |
化学工业 | 230篇 |
金属工艺 | 38篇 |
机械仪表 | 40篇 |
建筑科学 | 52篇 |
矿业工程 | 7篇 |
能源动力 | 61篇 |
轻工业 | 150篇 |
水利工程 | 26篇 |
石油天然气 | 1篇 |
无线电 | 251篇 |
一般工业技术 | 269篇 |
冶金工业 | 5253篇 |
原子能技术 | 19篇 |
自动化技术 | 184篇 |
出版年
2021年 | 10篇 |
2020年 | 15篇 |
2019年 | 17篇 |
2018年 | 27篇 |
2017年 | 22篇 |
2016年 | 30篇 |
2015年 | 19篇 |
2014年 | 27篇 |
2013年 | 75篇 |
2012年 | 57篇 |
2011年 | 69篇 |
2010年 | 46篇 |
2009年 | 57篇 |
2008年 | 59篇 |
2007年 | 76篇 |
2006年 | 54篇 |
2005年 | 53篇 |
2004年 | 54篇 |
2003年 | 37篇 |
2002年 | 48篇 |
2001年 | 53篇 |
2000年 | 31篇 |
1999年 | 198篇 |
1998年 | 1557篇 |
1997年 | 859篇 |
1996年 | 591篇 |
1995年 | 314篇 |
1994年 | 292篇 |
1993年 | 316篇 |
1992年 | 54篇 |
1991年 | 101篇 |
1990年 | 82篇 |
1989年 | 116篇 |
1988年 | 104篇 |
1987年 | 77篇 |
1986年 | 88篇 |
1985年 | 81篇 |
1984年 | 17篇 |
1983年 | 27篇 |
1982年 | 37篇 |
1981年 | 41篇 |
1980年 | 70篇 |
1979年 | 24篇 |
1978年 | 34篇 |
1977年 | 150篇 |
1976年 | 301篇 |
1975年 | 18篇 |
1974年 | 19篇 |
1973年 | 14篇 |
1972年 | 14篇 |
排序方式: 共有6609条查询结果,搜索用时 31 毫秒
81.
82.
83.
84.
MH West RE Barsley JE Hall S Hayne M Cimrmancic 《Canadian Metallurgical Quarterly》1992,37(6):1480-1488
This article is a discussion of the use of narrow-band light sources coupled with cameras equipped with band-pass filters to document patterned injuries on human skin. Several case reports are included. 相似文献
85.
We have isolated a putative serine/threonine receptor kinase gene with an expression pattern indicating that it may play a role in the stylar response to pollination. Differential display PCR was used to select tobacco mRNAs with increased accumulation following pollination. NTS16, a cDNA identified by this method, is homologous to a ca. 2.4 kb mRNA primarily expressed in pistil tissues. Levels of this mRNA increase during floral development and are further increased by pollination reaching maximal accumulation 12-18 hours after pollination and then declining. mRNA levels can also be increased by the application of ethylene to unpollinated flowers. A polypeptide encoded by the NTS 16 open reading frame has sequence similarity to the catalytic domain of several receptor protein kinases from plants including the S-receptor kinases implicated in the rejection of self-pollen in Brassica species and the Pto gene product of tomato which confers resistance to a bacterial pathogen. 相似文献
86.
LB Corbeil RP Gogolewski I Kacskovics KH Nielsen RR Corbeil JL Morrill R Greenwood JE Butler 《Canadian Metallurgical Quarterly》1997,61(3):207-213
AIMS/BACKGROUND: To characterise clinically a large kindred segregating retinitis pigmentosa and sensorineural hearing impairment in an autosomal dominant pattern and perform genetic linkage studies in this family. Extensive linkage analysis in this family had previously excluded the majority of loci shown to be involved in the aetiologies of RP, some other forms of inherited retinal degeneration, and inherited deafness. METHODS: Members of the family were subjected to detailed ophthalmic and audiological assessment. In addition, some family members underwent skeletal muscle biopsy, electromyography, and electrocardiography. Linkage analysis using anonymous microsatellite markers was performed on DNA samples from all living members of the pedigree. RESULTS: Patients in this kindred have a retinopathy typical of retinitis pigmentosa in addition to a hearing impairment. Those members of the pedigree examined demonstrated a subclinical myopathy, as evidence by abnormal skeletal muscle histology, electromyography, and electrocardiography. LOD scores of Zmax = 3.75 (theta = 0.10), Zmax = 3.41 (theta = 0.10), and Zmax = 3.25 (theta = 0.15) respectively were obtained with the markers D9S118, D9S121, and ASS, located on chromosome 9q34-qter, suggesting that the causative gene in this family may lie on the long arm (q) of chromosome 9. CONCLUSIONS: These data indicate that the gene responsible for the phenotype in this kindred is located on chromosome 9 q. These data, together with evidence that a murine deafness gene is located in a syntenic area of the mouse genome, should direct the research community to consider this area as a candidate region for retinopathy and/or deafness genes. 相似文献
87.
88.
Carsey F.D. Argus S.A.D. Collins M.J. Holt B. Livingstone C.E. Tang C.L. 《Geoscience and Remote Sensing, IEEE Transactions on》1989,27(5):468-482
Ice observations, results, and conclusions are summarized for the March 1987 Labrador Ice Margin Experiment (LIMEX'87), an international oceanographic study conducted in the pack ice of the Grand Banks area off the coast of Newfoundland. Included are the ice extent, flow size and thickness, ice kinematics and rheology, ice microwave properties, oceanic properties under the ice, and penetration of swell into the ice 相似文献
89.
M. T. Collins Ph.D. E. J. McConaghy B. Chem. Eng. B.Sc. R. F. Stauffer B.Sc. G. J. Desroches B.Sc. B. D. Krysa B.Sc. 《JOM Journal of the Minerals, Metals and Materials Society》1994,46(4):51-58
The first commercial application of the Sherritt two-stage zinc pressure leach process commenced operation at the Hudson Bay Mining and Smelting Company metallurgical complex in Flin Flon, Manitoba (Canada), on July 2, 1993. The start-up was relatively smooth, and full design rate for the plant was achieved by September 12, 1993. Since that time, zinc extraction in the zinc pressure leach plant has consistently been in excess of 98%, and production has continued to exceed expectations. The successful operation of the Hudson Bay plant represents a significant advancement of zinc processing technology, especially with respect to meeting the environmental challenge faced by zinc plants today. 相似文献
90.
P Collins M Watts M Brocklesby B Gerritsen P Veys 《Canadian Metallurgical Quarterly》1997,96(3):644-646
Familial haemophagocytic lymphohistiocytosis (HLH) is a disease with a very poor prognosis unless patients receive a bone marrow transplant. It is often difficult to find an HLA-matched donor and haploidentical familial donors may be considered. The main complication of this type of transplant is graft rejection. We describe a patient with familial HLH who received a haploidentical transplant using both mobilized peripheral blood and bone marrow stem cells in an attempt to overcome graft rejection by increasing the stem cell dose. The peripheral blood stem cell inoculum was CD34 enriched using a Cellpro column and T-cell depleted by Campath-1M, the patient received conditioning for a matched sibling donor transplant with the addition of Campath 1G. There was rapid and full engraftment and the patient remains disease free at 5 months. This technique may be applicable for other fatal inborn errors in the absence of an HLA-matched donor. 相似文献