全文获取类型
收费全文 | 498篇 |
免费 | 6篇 |
专业分类
电工技术 | 6篇 |
化学工业 | 82篇 |
金属工艺 | 7篇 |
机械仪表 | 6篇 |
建筑科学 | 16篇 |
矿业工程 | 1篇 |
能源动力 | 5篇 |
轻工业 | 38篇 |
水利工程 | 1篇 |
无线电 | 69篇 |
一般工业技术 | 88篇 |
冶金工业 | 93篇 |
原子能技术 | 12篇 |
自动化技术 | 80篇 |
出版年
2023年 | 3篇 |
2022年 | 7篇 |
2021年 | 11篇 |
2019年 | 10篇 |
2018年 | 9篇 |
2017年 | 4篇 |
2016年 | 5篇 |
2015年 | 6篇 |
2014年 | 6篇 |
2013年 | 20篇 |
2012年 | 14篇 |
2011年 | 28篇 |
2010年 | 25篇 |
2009年 | 15篇 |
2008年 | 20篇 |
2007年 | 15篇 |
2006年 | 20篇 |
2005年 | 24篇 |
2004年 | 12篇 |
2003年 | 20篇 |
2002年 | 7篇 |
2001年 | 6篇 |
2000年 | 6篇 |
1999年 | 11篇 |
1998年 | 30篇 |
1997年 | 22篇 |
1996年 | 15篇 |
1995年 | 9篇 |
1994年 | 13篇 |
1993年 | 9篇 |
1992年 | 5篇 |
1991年 | 10篇 |
1990年 | 6篇 |
1989年 | 4篇 |
1988年 | 5篇 |
1986年 | 3篇 |
1985年 | 3篇 |
1984年 | 4篇 |
1982年 | 7篇 |
1980年 | 6篇 |
1977年 | 3篇 |
1976年 | 6篇 |
1975年 | 4篇 |
1973年 | 5篇 |
1971年 | 2篇 |
1970年 | 2篇 |
1968年 | 2篇 |
1967年 | 2篇 |
1965年 | 2篇 |
1963年 | 2篇 |
排序方式: 共有504条查询结果,搜索用时 15 毫秒
71.
Einfluß von Wärmedehnungen auf das Spannungs- und Dehnungsverhalten fester Körper und Formulierung der Spannungs- und Dehnungsbeziehungen in Matrizenform für ebene und axialsymmetrische Probleme. Überprüfung der Aussagemöglichkeiten des Verfahrens anhand von Anwendungsbeispielen. 相似文献
72.
K Herholz U Pietrzyk J Voges R Schr?der M Halber H Treuer V Sturm WD Heiss 《Canadian Metallurgical Quarterly》1993,79(6):853-858
To determine histological correlates of the variability of glucose consumption in astrocytomas, the authors performed positron emission tomography (PET) with 18F-2-fluoro-2-deoxy-D-glucose (FDG) and matched the PET scans three-dimensionally with computerized tomography scans obtained in a stereotactic frame before biopsy. Ten patients with astrocytomas of World Health Organization Grade 2 or 3 were studied; patients with glioblastomas, oligodendrogliomas, or oligoastrocytomas were excluded from the study to avoid any confounding effects of different cell types and necroses. In samples of pure tumor, glucose consumption correlated significantly with cell density, but not with nuclear polymorphism. It is concluded that tumor cell density is a major determinant of glucose consumption in astrocytomas. The use of PET with FDG may help to locate the highest cell density and thus improve the diagnostic yield of stereotactic biopsy. 相似文献
73.
74.
M Fridkis-Hareli D Teitelbaum I Pecht R Arnon M Sela 《Canadian Metallurgical Quarterly》1997,9(7):925-934
Copolymer 1 (Cop 1), a synthetic copolymer of amino acids, effective in suppression of experimental allergic encephalomyelitis (EAE) and myelin basic protein (MBP), was shown to bind extensively and promiscuously to the class II MHC molecules on antigen-presenting cells (APC) without prior processing. In the case of human APC, binding has earlier been demonstrated to DR but not DQ or class I molecules. In the present study, we examined whether binding of Cop 1 and MBP affects MHC class II expression on the cell membrane. Biotinylated derivatives of these antigens were used to monitor their direct binding to MHC molecules on living APC by flow cytometry using phycoerythrin-streptavidin, while the levels of MHC surface expression were monitored by staining with FITC-conjugated anti-class I- and class II-specific antibodies. When Cop 1 or MBP were incubated with the APC, intensity of cell staining with anti-DR, but not with anti-DQ or anti-class I antibodies, was significantly increased, compared to the staining of control APC not reacted with these antigens. In contrast, staining intensity was unaffected when p84-102, a human immunodominant epitope of MBP, or ovalbumin (OVA), a protein which undergoes proteolytic degradation prior to binding, were incubated with the APC. Cycloheximide, a protein synthesis inhibitor, had no effect on the enhanced staining intensity with anti-DR antibody of cells treated with Cop 1 or MBP, whereas it inhibited the enhanced staining of both DR and DQ molecules caused by the respective antibodies, in the absence of these antigens. Brefeldin A, a protein transport inhibitor, lowered the levels of staining intensity with anti-DR and anti-DQ antibodies in both cases, with and without antigen added to the APC. Fluorescence microscopic analysis revealed that cells incubated with Cop 1 or MBP, but not with p84-102 or OVA, exhibit both bright staining of the cell membrane and clusters produced by the aggregation of DR molecules with these antigens. Taken together, these observations indicate that Cop 1 and MBP, due to their polyvalent character, lead to increased fluorescence intensity of their complexes with HLA-DR, possibly due to recruitment and clustering of previously synthesized DR molecules. This can explain the efficient binding of these antigens to the MHC class II molecules. 相似文献
75.
76.
Measurements of mid-infrared (MIR) absorption spectra of water and heavy water were carried out by fiber-optic evanescent wave spectroscopy, using silver halide (AgClBr) infrared fibers. Such measurements were performed for the first time on one sample, during the solid-liquid phase transition. From the variation of the spectra with temperature we found a new isosbestic point (at 3280 cm(-1) for H(2)O or at 2475 cm(-1) for D(2)O) and we identified five components of the O-H (O-D) stretch band. These phenomena have provided new information about the molecular structure of water. 相似文献
77.
We present an improved concept of laser firefly clustering for atmospheric probing, elaborating on previous published work. The laser firefly cluster is a mobile, flexible, and versatile distributed-sensing system, whose purpose is to profile the chemical and the particulate composition of the atmosphere for pollution monitoring, meteorology, detection of contamination, etc. The fireflies are deployed in situ at the altitude of interest and evoke a backscatter response from aerosols and molecules in the immediate vicinity by using a coded laser signal. The enhanced, second-generation system affords better performance at lower energy cost and has a considerably increased scope of application. A numerical example demonstrates the potential of the innovative system. 相似文献
78.
D. Sturm W. Stoppler P. Julisch K. Hippelein J. Muz 《Nuclear Engineering and Design》1982,72(1):81-95
The burst behaviour of fourteen vessels containing longitudinal flaws was investigated. The vessels were made of the two steels: 20 MnMoNi 5 5 with a high upper shelf impact toughness and a special melt of 22 NiMoCr 3 7 with a low upper-shelf impact toughness. The dimensions of the vessels were the same as of the pipes of the primary coolant system (798 O.D. × 47.5 mm wall thickness) of a pressurized water reactor. The test pressure and temperature correspond with the real service conditions of a PWR.Using a highly sophisticated measuring equipment, the time-history of pressure, crack opening and crack-opening area were determined experimentally. 相似文献
79.
The ability of the "conceptual-area" scoring system to differentiate between tuberculous, process schizophrenic, reactive schizophrenic, and brain-damaged patients was tested by administering the Object Sorting Test to 125 hospitalized veterans. The diagnostic groups were equivalent in mean education, intelligence, and length of hospitalization, but the tuberculous and brain-damaged patients averaged 8 yr. older than the schizophrenics. None of the scores differentiated the groups at the .05 level. In discussing these results, it was maintained that, contrary to comment in the literature, "conceptual area" has never conclusively differentiated, in a simultaneous comparison, between nonpsychiatric, brain-damaged, and schizophrenic patients, and may not be appropriate for this purpose. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
80.