全文获取类型
收费全文 | 614篇 |
免费 | 5篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 17篇 |
综合类 | 1篇 |
化学工业 | 118篇 |
金属工艺 | 5篇 |
机械仪表 | 14篇 |
建筑科学 | 11篇 |
矿业工程 | 1篇 |
能源动力 | 17篇 |
轻工业 | 51篇 |
水利工程 | 1篇 |
无线电 | 75篇 |
一般工业技术 | 70篇 |
冶金工业 | 198篇 |
原子能技术 | 12篇 |
自动化技术 | 29篇 |
出版年
2022年 | 3篇 |
2021年 | 15篇 |
2020年 | 4篇 |
2019年 | 2篇 |
2018年 | 6篇 |
2017年 | 2篇 |
2016年 | 7篇 |
2015年 | 5篇 |
2014年 | 11篇 |
2013年 | 17篇 |
2012年 | 19篇 |
2011年 | 22篇 |
2010年 | 17篇 |
2009年 | 12篇 |
2008年 | 21篇 |
2007年 | 25篇 |
2006年 | 13篇 |
2005年 | 23篇 |
2004年 | 14篇 |
2003年 | 13篇 |
2002年 | 11篇 |
2001年 | 6篇 |
2000年 | 19篇 |
1999年 | 13篇 |
1998年 | 73篇 |
1997年 | 50篇 |
1996年 | 24篇 |
1995年 | 25篇 |
1994年 | 21篇 |
1993年 | 22篇 |
1992年 | 3篇 |
1991年 | 9篇 |
1990年 | 8篇 |
1989年 | 9篇 |
1988年 | 4篇 |
1987年 | 8篇 |
1986年 | 7篇 |
1985年 | 13篇 |
1984年 | 3篇 |
1983年 | 5篇 |
1982年 | 4篇 |
1981年 | 6篇 |
1980年 | 3篇 |
1979年 | 5篇 |
1978年 | 3篇 |
1977年 | 2篇 |
1976年 | 6篇 |
1973年 | 3篇 |
1972年 | 2篇 |
1959年 | 1篇 |
排序方式: 共有620条查询结果,搜索用时 15 毫秒
191.
Hisashi Kodama Keiko Mochizuki Masahiro Kohno Akio Ohnishi Yasumasa Kuwahara 《Journal of chemical ecology》1987,13(8):1859-1869
Stegobinone, (2S, 3R, 1R)-2,3,-dihy dro-2,3,5-trimethyl-6-(1-methyl-2-oxobutyl)-4H-pyran-4-one, the sex pheromone of drugstore beetles (Stegobium paniceum L.), elicited the pheromonal response from the males of the species in our bioassay system; however, the synthesized diastereomeric mixture of this compound was actually inactive to the males. Although the stegobinone isolated from the beetles of this species had significant activity, its enantiomeric [(±)-2S,3R,1S-] and diatereomeric [(±)-2S,3S,1RS-] isomers were inactive. Adding the (±)-2S,3R,1S isomer to stegobinone significantly reduced the male response. Furthermore, the activity of Stegobinone vanished on keeping it at room temperature for two weeks. In such a stored stegobinone sample, the presence of 2S,3R,1S isomer, the inhibitory component, was confirmed. This isomer might be produced by C-1 epimerization during storage. 相似文献
192.
The high temperature electron spin resonance technique has been used to obtain in situ information on the behaviour of liquefaction catalysts during coal pyrolysis. The spin concentration in coal was induced in the presence of a catalyst at the pyrolysis temperature. ZnCl2 drastically increased the spin concentration of coal. The order of activity of the catalysts with respect to the increase in spin concentration was: ZnCl2 (impregnated) ?ZnCl2 (dispersed) >ZnCl2/KCl>SnCl2 > SbCl3≈AlCl3 ≈CaCl2 > coal alone. 相似文献
193.
K Hirano N Shimojo K Saito A Hoshioka T Katsuki K Homma Y Kohno H Niimi 《Canadian Metallurgical Quarterly》1995,44(9):1117-1124
Nasal smear cytology was studied in pediatric patients with bronchial asthma with special reference with IgE RAST to house dust mite, Dermatophagoides pteronyssinus (Dp). Results obtained were as follows: (1) Numbers of eosinophils on the nasal smear correlated well with Dp RAST score, (2) mast cells were detected before Dp RAST becoming positive and appearance of eosinophils, (3) basophils appeared after detection of eosinophils and only in patients with nasal smear eosinophils. These results suggest that mast cells are the early marker for allergic inflammation and basophils and eosinophils appear in association with overt sensitization with house dust mite in house dust mite-sensitized asthmatic patients. 相似文献
194.
A new pH indicator, seminaphthofluorescein (SNAFL)-calcein acetoxymethyl ester, was used for intracellular pH (pHi) measurement in living MDCK cells with a laser scanning confocal microscope (LSCM) equipped with an Argon/Krypton laser and dual-excitation and dual-emission (FITC/Texas Red) filter set. SNAFL-calcein excitation maxima are approximately 492/540 nm (acid/base) and emission maxima are approximately 535/625 nm (acid/base) with a pKa value at approximately 7.0. The absorption/emission spectra of SNAFL-calcein indicate that the ratio of emission intensities of its basic/acidic forms is pH dependent. With an Argon/Krypton LSCM, we were able to monitor the acidic and basic forms of this dye simultaneously using dual-excitation (488/568 nm) and dual-emission (525-614 nm/> or = 615 nm) wavelengths (lambda s). The simultaneous dual-excitation/emission LSCM system allows for efficient recording of pHi dynamics (time resolution approximately 1 sec) in living cells. We have analyzed emission stability of the dye at different temperatures (22 degrees C and 37 degrees C) and constant pH, and at the same temperature (22 degrees C) but various pHs (6.6, 7.0, and 7.4). Bleaching rate is slightly higher at 37 degree C than that at 22 degrees C. The basic form of the dye (lambda Em approximately 625 nm) has a slightly higher bleaching rate than the acidic form (lambda Em approximately 535 nm) in standard culture medium (pH 7.3) at either 22 degree C or 37 degrees C. The pHi in MDCK cells calculated from ratio images (535 nm/625 nm) was 7.19 +/- 0.03 (mean +/- SEM, n = 20). Calibration experiments show that the useful pH range of SNAFL-calcein appears to be between 6.2 and 7.8, as the dye is difficult to calibrate outside this pH range. 相似文献
195.
Takashi Yoshida Kenichi Nishizawa Masahiro Tabata Hiroshi Abe Tatsuya Kodama Masamichi Tsuji Yutaka Tamaura 《Journal of Materials Science》1993,28(5):1220-1226
The methanation reaction of CO2 was studied with H2-reduced magnetite. A high conversion ratio of about 0.9 (in 30 min of the reaction time) with a selectivity of nearly 100% was obtained at 300°C and at 0.1 MPa for H2-reduced magnetite which had been prepared by passing H2 gas for 1–5 h at 300°C. From the results of X-ray diffractometry and Mössbauer spectroscopy, and from chemical analysis of the deposited carbon, H2-reduced magnetite is considered to decompose adsorbed CO2 into carbon, and to incorporate the oxygen of the CO2 into the spinel-type structure of the magnetite, associated with oxidation of the Fe2+ ion into Fe3+ ion in the magnetite. The high conversion ratio in the methanation reaction is considered to come from a higher reactivity of the elementary carbon deposited on the surface of the H2-reduced magnetite. 相似文献
196.
N Shimojo T Katsuki K Saito O Tarutani Y Kohno H Niimi 《Canadian Metallurgical Quarterly》1994,17(3):203-207
In order to investigate the regulation of autoimmune response to thyroglobulin (Tg), one of the thyroid autoantigens, we established a Tg-specific T cell line by stimulation of peripheral blood mononuclear cells from a healthy volunteer with Tg and characterized its cytokine production pattern. The Tg-specific T cell line, designated DH5D1, obtained from a limiting dilution culture bore alpha beta T cell receptor and was CD4 and CD45RO positive. Upon stimulation with Tg, DH5D1 secreted little or no titers of IL-2, TNF-alpha, and IFN-gamma, whereas activation with combination of phorbol myristate acetate and calcium ionophore produced measurable levels of these cytokines. These results indicate that the Tg-specific T cell line is not defective in its capacity to produce proinflammatory cytokines and suggest that the inability of cytokine production by autoreactive T cells of healthy individuals is one fail-safe mechanism for preventing aggression of harmful autoimmune response. 相似文献
197.
N Kohno A Yokoyama Y Hirasawa K Kondo S Fujino M Abe K Hiwada 《Canadian Metallurgical Quarterly》1997,91(9):558-561
KL-6, a MUC1 mucin preferentially expressed in regenerating type 2 pneumocytes, has been reported to be a sensitive serum marker for evaluating the disease activity of interstitial pneumonitis (IP). Type III procollagen N-terminal peptide (PIIIP) and type IV collagen 7S (7S collagen) have also been reported to be useful in the serological evaluation of the activity. Their levels were measured and their serodiagnostic values were compared simultaneously in patients with IP and alveolar pneumonia. The study population was 45 patients with IP and 12 patients with alveolar pneumonia. Serum KL-6 levels were measured by a specific enzyme immunoassay, and both serum PIIIP and 7S collagen concentrations by their correspondent radioimmunoassay kits. There were no significant difference of serum C-reactive protein level, which was evaluated as an indicator of inflammatory process, between IP and alveolar pneumonia patients. In IP, the abnormally elevated rate of KL-6 [80% (36/45)] was significantly higher than those of PIIIP [40% (18/45)] and 7S collagen [40% (18/45)]. In alveolar pneumonia, the rate of KL-6 [0% (0/12)] was significantly lower than those of PIIIP [33% (4/12)] and 7S collagen [25% (3/12)]. There were no significant correlations among serum levels of the markers. These observations indicate that the serodiagnostic value of KL-6 for IP is superior to that of PIIIP and 7S collagen, and that KL-6 has a characteristic to discriminate IP from alveolar pneumonia. 相似文献
198.
199.
A 4-year-old boy presented with a rare case of an epidural tumor causing compression of the thoracic spinal cord manifesting as rapid worsening of gait disturbance. The tumor was grossly totally resected, and radiotherapy and chemotherapy were subsequently administered. The histological diagnosis was primitive neuroectodermal tumor. He has been free of recurrence for more than 6 years. Early tumor resection followed by chemotherapy and irradiation is recommended for patients with primitive neuroectodermal tumor and unstable symptoms. 相似文献
200.
Y Kaneko J Nakajima T Ohtsuka T Kohno A Furuse 《Canadian Metallurgical Quarterly》1995,43(8):1155-1159
61-year-old male was admitted to our hospital for surgical treatment of bronchogenic squamous cell carcinoma arising from left B8. The patient had right aortic arch with aberrant left subclavian artery and postaortic left brachiocephalic vein. Intraoperatively, left ligamentum arteriorsus forming vascular ring between the left subclavian artery and the pulmonary artery was found, however the ligamentum arteriorsus was not divided because no symptom of esophago-tracheal compression was observed. The left brachiocephalic vein was located between the ascending aorta and the arterial ligament. The lower lobe of the left lung was resected, and lymph nodes in the left side of the mediastinum were dissected easily because the aortic arch was positioned on the other side. Preoperative assessment of the type of branching and the course of arteries and veins is important for safe operation. 相似文献