全文获取类型
收费全文 | 1875篇 |
免费 | 50篇 |
国内免费 | 7篇 |
专业分类
电工技术 | 7篇 |
综合类 | 1篇 |
化学工业 | 302篇 |
金属工艺 | 51篇 |
机械仪表 | 24篇 |
建筑科学 | 21篇 |
矿业工程 | 1篇 |
能源动力 | 57篇 |
轻工业 | 62篇 |
水利工程 | 1篇 |
石油天然气 | 1篇 |
无线电 | 146篇 |
一般工业技术 | 324篇 |
冶金工业 | 813篇 |
原子能技术 | 4篇 |
自动化技术 | 117篇 |
出版年
2023年 | 19篇 |
2022年 | 14篇 |
2021年 | 25篇 |
2020年 | 17篇 |
2019年 | 17篇 |
2018年 | 30篇 |
2017年 | 28篇 |
2016年 | 30篇 |
2015年 | 19篇 |
2014年 | 53篇 |
2013年 | 77篇 |
2012年 | 59篇 |
2011年 | 59篇 |
2010年 | 40篇 |
2009年 | 49篇 |
2008年 | 51篇 |
2007年 | 41篇 |
2006年 | 35篇 |
2005年 | 27篇 |
2004年 | 18篇 |
2003年 | 33篇 |
2002年 | 25篇 |
2001年 | 26篇 |
2000年 | 25篇 |
1999年 | 40篇 |
1998年 | 194篇 |
1997年 | 135篇 |
1996年 | 95篇 |
1995年 | 68篇 |
1994年 | 53篇 |
1993年 | 62篇 |
1992年 | 22篇 |
1991年 | 30篇 |
1990年 | 18篇 |
1989年 | 15篇 |
1988年 | 17篇 |
1987年 | 14篇 |
1986年 | 10篇 |
1985年 | 23篇 |
1984年 | 17篇 |
1983年 | 13篇 |
1982年 | 23篇 |
1981年 | 17篇 |
1980年 | 31篇 |
1979年 | 15篇 |
1978年 | 12篇 |
1977年 | 49篇 |
1976年 | 110篇 |
1975年 | 9篇 |
1971年 | 6篇 |
排序方式: 共有1932条查询结果,搜索用时 15 毫秒
81.
82.
VS Paukov 《Canadian Metallurgical Quarterly》1996,122(12):604-610
83.
CA Vater LM Bartle JD Leszyk JM Lambert VS Goldmacher 《Canadian Metallurgical Quarterly》1995,270(21):12933-12940
Indirect immunofluorescence studies revealed that when fixed, permeabilized cultured human cells were incubated with ricin A chain, the toxin molecule localized in a staining pattern indicative of binding to the endoplasmic reticulum and to nucleoli. Chemical cross-linking experiments were performed to identify the cellular components that mediated the binding of ricin A chain. Conjugates were formed between 125I-labeled ricin A chain and two proteins present in preparations of total cell membranes and in samples of purified mammalian ribosomes. Specificity of the ricin A chain-ribosome interaction was demonstrated by inhibition of formation of the complexes by excess unlabeled ricin A chain, but not by excess unlabeled gelonin, another ribosome-inactivating protein. Complexes of ricin A chain cross-linked to the ribosomal proteins were purified and subjected to proteolytic digestion with trypsin. Amino acid sequencing of internal tryptic peptides enabled identification of the ricin A chain-binding proteins as L9 and L10e of the mammalian large ribosomal subunit. 相似文献
84.
Mechanical shaping of an aluminium alloy reinforced with Al2O3 particulates, (Al2O3)p-Al, was carried out by a cold rolling operation. Rolling was performed unidirectionally in a direction perpendicular to the extrusion direction of the composite, until edge cracks formed. Cold rolling was found to cause particulate cracking and interfacial debonding, as wellas the redistribution of (Al2O3)p. These parameters have significant roles in determining the elastic properties of the resultant composite. 相似文献
85.
M. Prikryl A. Kroupa G. C. Weatherly S. V. Subramanian 《Metallurgical and Materials Transactions A》1996,27(5):1149-1165
The precipitation behavior of a medium carbon steel microalloyed with Ti, V, and N has been studied by analytical transmission
electron microscopy in the as-cast and isothermally heat-treated states, as well as at different stages in the thermomechanical
processing of the steel. Mixed (Ti,V) nitrides were found in all the structures, but there was no evidence for mixed carbonitride
formation. The Hillert-Staffansson model was used to predict the composition of the nitrides as a function of tem-perature.
Upon prolonged aging many of the precipitates became “fragmented” and were no longer single crystals. At the same time, the
volume fraction of precipitates dropped, while their average Ti content increased. Possible explanations for this unexpected
behavior are discussed in this article. 相似文献
86.
GIu Sharaevski? LA Tiunov VV Chumakov VS Sukhorukov 《Canadian Metallurgical Quarterly》1996,317(8):66-70, 80
From position of the uniform concept of the accident medicine the problems of toxicological supply of the ships of MNF are considered. Peculiarities of chemical accidents in the ship conditions are marked. The question about principles of harmful chemical substances regulating, forming air environment of ship living quarters is discussed. The prospects of practical use of antidotal means, intended for protection of personnel from toxic action of carbon dioxide and chemical combinations, causing development of toxic edema of lungs are given. 相似文献
87.
88.
K Warren E Goldstein VS Hung JE Koehler W Richardson 《Canadian Metallurgical Quarterly》1998,116(7):937-940
A patient with the acquired immunodeficiency syndrome developed bilateral retinitis due to a Bartonella (formerly Rochalimaea) henselae infection. A retinal biopsy was performed when severe and progressive retinal infection failed to respond to empirical treatment for cytomegalovirus and Toxoplasma gondii. The biopsy specimen was stained with routine histopathological stains and the Steiner silver stain. Ribosomal DNA was extracted from formalinfixed, paraffin-embedded retinal tissue and amplified with the polymerase chain reaction assay, using Bartonella-specific primers. The amplified DNA fragment was cloned and sequenced. Staining with hematoxylin-eosin revealed tufts of proliferating vascular endothelium with numerous fusiformappearing cells, consistent with a diagnosis of bacillary angiomatosis. A Steiner silver stain revealed numerous small bacilli in the biopsy specimen. Amplification of DNA extracted from the tissue produced a fragment of 16S ribosomal DNA of the expected size; sequencing of the DNA fragment revealed that the infection was caused by B henselae. The retinal infection was treated with minocycline, doxycycline, and ciprofloxacin with improvement in visual acuity in the ensuing 12 weeks. To our knowledge, this is the first human immunodeficiency virus-infected patient with retinitis due to B henselae who was diagnosed by the identification of silver-staining bacilli and amplification and sequencing of B henselae with a polymerase chain reaction assay using a biopsy specimen of retinal tissue. Retinal biopsy is indicated, despite its potential for serious complications, in patients with acquired immunodeficiency syndrome who have a progressive, sight-threatening retinitis that is undiagnosed and unresponsive to therapy. 相似文献
89.
Cubic oxide pyrochlores, Ln2Mo2O7, Ln=SmYb,Y, (Nd1?xAx), A=Er and Yb; 0 < x < 1.0, have been synthesized and electrical properties were examined in the range 77-600K. Semiconductor behavior is observed for Ln=EuYb, Y but the resistivity and Ea are low. Sm2Mo2O7 and Nd1?xYbxMo2O7 (0.05 ≤ x ≤ 0.1) exhibit semimetallic or metallic behavior. The mechanism of conduction in these compounds is explained on the basis of band model proposed by Sleight et al. 相似文献
90.
[3-14C] Eicosatrienoic acid (Δ11,14,17) chemically synthesized from [1-14C] linolenic acid was injected intracranially into 14-day old rats and sacrificed 8 hr later. The analysis of brain fatty
acids by radio-gas liquid chromatography before and after ozonolysis showed that the tetraene fraction consisted of a desaturated
product, Δ5,11,17–20∶4, and its elongated product, Δ7,13,16,19–22∶4. Both of these products, with a combined total of 61%
of the total radioactivity recovered in the tetraene fraction, contain a nonmethylene interrupted double bond system and,
therefore, are unsuitable for further desaturation. The other two components, Δ6,9,12,15–18∶4 and Δ8,11,14,17–20∶4, must have
been formed from Δ9,12,15–18∶3, formed by retroconversion of the starting material 20∶3, followed by desaturation and elongation.
These results suggest a lack of Δ8 desaturase in the developing brain, leading to formation of Δ5,11,14,17–20∶4 rather than Δ8,11,14,17–20∶4. Howeve, the nonmethylene
interrupted double bond isomer does not restrict chain elongation. 相似文献