全文获取类型
收费全文 | 12321篇 |
免费 | 1292篇 |
国内免费 | 793篇 |
专业分类
电工技术 | 1028篇 |
综合类 | 1357篇 |
化学工业 | 1500篇 |
金属工艺 | 694篇 |
机械仪表 | 709篇 |
建筑科学 | 704篇 |
矿业工程 | 508篇 |
能源动力 | 369篇 |
轻工业 | 1243篇 |
水利工程 | 350篇 |
石油天然气 | 379篇 |
武器工业 | 239篇 |
无线电 | 1119篇 |
一般工业技术 | 954篇 |
冶金工业 | 1664篇 |
原子能技术 | 295篇 |
自动化技术 | 1294篇 |
出版年
2024年 | 81篇 |
2023年 | 213篇 |
2022年 | 471篇 |
2021年 | 553篇 |
2020年 | 460篇 |
2019年 | 287篇 |
2018年 | 319篇 |
2017年 | 342篇 |
2016年 | 296篇 |
2015年 | 495篇 |
2014年 | 621篇 |
2013年 | 769篇 |
2012年 | 922篇 |
2011年 | 937篇 |
2010年 | 939篇 |
2009年 | 831篇 |
2008年 | 861篇 |
2007年 | 892篇 |
2006年 | 650篇 |
2005年 | 584篇 |
2004年 | 451篇 |
2003年 | 281篇 |
2002年 | 259篇 |
2001年 | 219篇 |
2000年 | 211篇 |
1999年 | 99篇 |
1998年 | 363篇 |
1997年 | 248篇 |
1996年 | 157篇 |
1995年 | 81篇 |
1994年 | 73篇 |
1993年 | 85篇 |
1992年 | 23篇 |
1991年 | 18篇 |
1990年 | 16篇 |
1989年 | 20篇 |
1988年 | 16篇 |
1987年 | 9篇 |
1986年 | 15篇 |
1985年 | 11篇 |
1984年 | 4篇 |
1982年 | 10篇 |
1981年 | 7篇 |
1980年 | 13篇 |
1979年 | 4篇 |
1978年 | 4篇 |
1977年 | 58篇 |
1976年 | 99篇 |
1961年 | 7篇 |
1959年 | 5篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
12.
13.
介绍了平板显示控制芯片TO944的特点、功能、原理,并给出了基于T0944芯片的新型平板显示接口卡的软硬件实现方案,该方案具有电路简单、高可靠性、高性价比、高显示质量等优点,可用于各种不同类型与不同尺寸的平板显示器的显示。 相似文献
14.
15.
II Kalachev AN Baídus' OA Ivanova EA Ganina IA Boldyrev EA Svetoch 《Canadian Metallurgical Quarterly》1997,(6):32-37
Unlike the glanders agent, the superficial structures of the melioidosis agent were demonstrated to be responsible for marked was immunosuppressive activity. Some antigenic fractions suppressing the blast transformation of lymphocytes, reducing the count of T helpers and profoundly potentiating the infection in vivo were isolated from P. pseudomallei cells. The immunogenic and immunosuppressive activities of both agents' superficial structures were studied by high performance chromatography. Antigenic complexes that were able to protect immunized laboratory animals against fatal infections and to prevent bacterial carriage due to the activation of T cells and to the bacterial activity of macrophages were identified. A composition comprising several immunogens was found to provide an additive protective action against both causative agents. Therefore, the composition may be considered to be a prototype of a molecular antipseudomonadic vaccine. 相似文献
16.
M Beksa? MS Beksa? VB Tipi HA Duru MU Karakás AN Cakar 《Canadian Metallurgical Quarterly》1997,30(3):145-150
The endothelium participates actively in homeostatic mechanisms such as the regulation of vascular tone and maintenance of a nonthrombotic environment, as well as directing biological responses such as leukocyte trafficking to inflammatory sites. Disruption of these processes leads to disease. In the antiphospholipid antibody syndrome autoantibodies provoke the endothelium to develop a prothrombotic surface. In systemic vasculitides associated with presence of antineutrophil cytoplasm antibodies, it is likely that the autoantibodies incite premature neutrophil activation, disrupted neutrophil-endothelium interactions and endothelial damage. This review considers how normal endothelial functions may be subverted in disease and how active endothelial responses may contribute to disease. 相似文献
17.
18.
NW Tomkins NN Jonsson MP Young AN Gordon KA McColl 《Canadian Metallurgical Quarterly》1997,75(10):722-723
On the basis of clinical signs and histological findings eight 9-month-old male rusa deer (Cervus timorensis) were diagnosed with sheep associated-malignant catarrhal fever. Following a variable course involving rectal temperatures around 40.5 degrees C, depression, inappetence, diarrhoea, corneal opacity and hypopyon all animals died or were euthanased over a 5-week period. Severe multifocal vasculitis, mainly periglomerular and in the arcuate vessels were consistent histological findings which in the past have been adequate to confirm clinical diagnosis of sheep associated-malignant catarrhal fever. A nested polymerase chain reaction test has been used to detect a sheep associated-malignant catarrhal fever PRC product, 238 base-pairs in size, in DNA extracted from lymphocyte preparations. The result supported the diagnosis of sheep associated-malignant catarrhal fever in these deer. 相似文献
19.
AN Parkhomenko 《Canadian Metallurgical Quarterly》1997,69(6):55-59
The aim of the study was to discover determinants of the onset of life threatening ventricular tachyarrhythmia. 102 patients with acute myocardial infarction and 32 patients with postinfarction cardiosclerosis were examined. The data gained at programmed ventricular stimulation, high resolution ECG, Holter ECG monitoring, spectral analysis of cardiac rhythm variability and two-dimension echocardiography proved the importance of early postinfarction left ventricular dilatation in the onset of electrical cardiac instability, establishment of anatomic substrate of monomorphic ventricular tachycardias, low variability of cardiac rhythm. The findings evidence that MI patients with late ventricular potentials and end-diastolic left ventricular index above 100 ml/m2 in subacute period may be considered as a group of high risk in need of individual approach and further therapy. The discovered lowering of informative value of non-invasive methods in patients late after MI dictates the necessity of new approaches to detection of electrophysiological disturbances and sudden death risk in registration of postinfarction dilatation of the heart. 相似文献
20.
Experimental results are presented to show that the adhesion force is the single most important limiting factor in high-resolution atomic force microscopy of DNA in air, prepared by the cytochrome-C-assisted spreading method. It is also shown that humidity plays a minor role in the control of probe force. Using a pure carbon film as the substrate to clean the AFM tip prior to imaging, it is demonstrated that 4-6 nm resolution on DNA can be routinely obtained by the atomic force microscope with commercial Si3N4 pyramid cantilevers. We also show that in organic solvents a resolution of up to 3 nm can be obtained under optimal conditions. 相似文献