全文获取类型
收费全文 | 910篇 |
免费 | 34篇 |
国内免费 | 2篇 |
专业分类
电工技术 | 62篇 |
综合类 | 4篇 |
化学工业 | 271篇 |
金属工艺 | 10篇 |
机械仪表 | 19篇 |
建筑科学 | 33篇 |
能源动力 | 33篇 |
轻工业 | 99篇 |
水利工程 | 5篇 |
石油天然气 | 2篇 |
无线电 | 52篇 |
一般工业技术 | 133篇 |
冶金工业 | 119篇 |
原子能技术 | 27篇 |
自动化技术 | 77篇 |
出版年
2023年 | 7篇 |
2022年 | 15篇 |
2021年 | 23篇 |
2020年 | 6篇 |
2019年 | 17篇 |
2018年 | 17篇 |
2017年 | 13篇 |
2016年 | 18篇 |
2015年 | 20篇 |
2014年 | 31篇 |
2013年 | 56篇 |
2012年 | 28篇 |
2011年 | 54篇 |
2010年 | 42篇 |
2009年 | 40篇 |
2008年 | 46篇 |
2007年 | 42篇 |
2006年 | 34篇 |
2005年 | 32篇 |
2004年 | 27篇 |
2003年 | 33篇 |
2002年 | 27篇 |
2001年 | 12篇 |
2000年 | 16篇 |
1999年 | 14篇 |
1998年 | 50篇 |
1997年 | 37篇 |
1996年 | 21篇 |
1995年 | 15篇 |
1994年 | 12篇 |
1993年 | 16篇 |
1992年 | 6篇 |
1991年 | 8篇 |
1990年 | 9篇 |
1989年 | 4篇 |
1988年 | 10篇 |
1986年 | 4篇 |
1985年 | 3篇 |
1984年 | 10篇 |
1983年 | 5篇 |
1982年 | 5篇 |
1980年 | 3篇 |
1979年 | 9篇 |
1978年 | 6篇 |
1977年 | 8篇 |
1976年 | 7篇 |
1975年 | 5篇 |
1972年 | 3篇 |
1968年 | 3篇 |
1963年 | 3篇 |
排序方式: 共有946条查询结果,搜索用时 15 毫秒
891.
T. K. Miwa 《Journal of the American Oil Chemists' Society》1963,40(7):309-313
Some of the known principles of gas-liquid chromatography are reviewed. Application of the equivalent chain length (ECL) method
to identification of complex molecules, and to prediction of structures of unknowns, is described in detail.
A laboratory of the No. Utiliz. Res. & Dev. Div., ARS, U.S.D.A. 相似文献
892.
Junichi Nishino Shigeo Ohshio Kiichiro Kamata 《Journal of the American Ceramic Society》1992,75(12):3469-3472
Aluminum-doped zinc oxide films prepared using a normal-pressure CVD (NP-CVD) method were studied as a transparent electrode material. The films were prepared on fused quartz substrates at 500°C using bis(2,4-pentanedionato)zinc and tris(2,4-pentanedionato)aluminum as source material. The transparent films, ∼0.3 μm in thickness, with a transmittance above 80% at a wavelength between 400 and 820 nm, were easily obtained. The optical band gap of the films increased from 3.3 to 3.6 eV with increasing amounts of aluminum dopant. The minimum resistivity of the film was about 4.9 × 10−5 Ω·m. 相似文献
893.
Kozo Tanabe Hideshi Hattori Tsutomu Yamaguchi Susumu Yokoyama Junichi Umematsu Yuzo Sanada 《Fuel》1982,61(4):389-390
The catalytic activity of Fe2O3for the hydrocracking of a bituminous coal at 673K increases when a small amount of SO42? is included in the catalyst. The effect of SO42? is marked in the formation of resins, stronger polar compounds and asphaltenes. 相似文献
894.
To clarify the concept framework to assess web based information systems (WIS) evolution from an information perspective instead of the usual systems perspective, and to seek for in-depth understanding of maturing patterns of WISs based on the framework, several central concepts related to the information aspect of WIS are firstly discussed, then a growth model of local government websites based on a survey study is proposed. 相似文献
895.
M Mizutani H Miwa T Takahashi K Katoh M Shikami N Katayama H Shiku K Kita 《Canadian Metallurgical Quarterly》1997,66(4):479-491
Of 832 acute leukemia patients, including 580 acute myeloblastic leukemia (AML), 197 pre-B acute lymphoblastic leukemia (ALL) and 55 pre-T ALL, 26 cases (3.1%) of CD13/CD33+CD7+CD19+ acute leukemia were found. A total of 20 patients were diagnosed as AML, two as pre-B ALL and four as pre-T ALL. Based on the relative intensity of expression of CD7 and CD19, CD13/CD33+CD7+CD19+ acute leukemia patients were subclassified into three categories. Type I (CD7 > CD19) included ten AML and four pre-T ALL, having cellular characteristics similar to CD7+ AML and CD13/CD33+CD7+ ALL. Type II (CD7 < CD19) consisted of four AML with t(8;21) and two pre-B ALL. Type III (CD7 = CD19) included six AML. CD13/CD33+CD7+CD19+ acute leukemia frequently expressed stem cell associated molecules, such as CD34 (88.5%), HLA-DR (96.2%) and mRNA for MDR1 (72.2%), GATA-2 (87.5%) and SCL (25.0%). Simultaneous expression of cytoplasmic CD3 and myeloperoxidase in some leukemia cells implies that CD13/CD33+CD7+CD19+ acute leukemia cells have the potential to differentiate into various lineages. These data suggest that a small population of acute leukemia patients with distinct phenotype, CD13/CD33+CD7+CD19+ acute leukemia, may originate from hematopoietic stem cells. 相似文献
896.
S Nakamura T Akisue H Jinnai T Hitomi S Sarkar N Miwa T Okada K Yoshida S Kuroda U Kikkawa Y Nishizuka 《Canadian Metallurgical Quarterly》1998,95(21):12249-12253
Sequence analysis of a heat-stable protein necessary for the activation of ADP ribosylation factor-dependent phospholipase D (PLD) reveals that this protein has a structure highly homologous to the previously known GM2 ganglioside activator whose deficiency results in the AB-variant of GM2 gangliosidosis. The heat-stable activator protein indeed has the capacity to enhance enzymatic conversion of GM2 to GM3 ganglioside that is catalyzed by beta-hexosaminidase A. Inversely, GM2 ganglioside activator purified separately from tissues as described earlier [Conzelmann, E. & Sandhoff, K. (1987) Methods Enzymol. 138, 792-815] stimulates ADP ribosylation factor-dependent PLD in a dose-dependent manner. At higher concentrations of ammonium sulfate, the PLD activator protein apparently substitutes for protein kinase C and phosphatidylinositol 4,5-bisphosphate, both of which are known as effective stimulators of the PLD reaction. The mechanism of action of the heat-stable PLD activator protein remains unknown. 相似文献
897.
Y Konishi M Matsumoto S Yuasa T Miwa J Nishizawa 《Canadian Metallurgical Quarterly》1994,47(9):705-708
Postoperative right ventricular function was evaluated serially by thermodilution techniques (REF-1, Edwards Laboratories) in patients who underwent aorto-coronary bypass surgery with uneventful postoperative recovery. The patients were divided into three groups depending on the location of critical stenosis of the right coronary artery. The stenosis was proximal to the right ventricular branch in group I (n = 13), distal to the right ventricular branch but proximal to the acute marginal branch in group II (n = 13) and distal to the acute marginal branch in group III (n = 11). Control (n = 20) consisted of the patients with no significant stenosis of the right coronary artery. Cardiac index, intracardiac pressures and amount of cathecolamin used during postoperative course showed no significant differences among the groups including control. With the use of cathecolamine after surgery, right ventricular ejection fraction (RVEF) rose and right ventricular volumes (RVEDV and RVESV) decreased in all the groups except for group I. These values in group I were unchanged. Thus, there were significant differences in RVEF, RVEDV and RVESV between group I and control. These results mean that right ventricular dysfunction may remain even long after occlusion of the proximal right coronary artery. 相似文献
898.
Two cases of vertebral artery injury following mild neck trauma are reported. A 52-year-old man was hospitalized with gait disturbance 7 days after mild traffic accident. Right vertebral angiogram revealed complete occlusion of the rt. vertebral artery (VA) and MR images revealed infarction in the rt. cerebellar hemisphere and rt. dorsolateral part of the medulla oblongata and revealed the thrombus in the rt. VA. He underwent anticoagulation and became asymptomatic. Angiogram 6 months later revealed the vessel to be normal. A 23-year-old man who has a habit of self-manipulation of his neck was hospitalized on the day when he experienced dysesthesia in the left part of his face and left upper and lower extremities and unsteady gait. MR images revealed multiple infarction in bilateral cerebellar hemispheres and thrombus in bilateral VAs. Bilateral vertebral angiogram revealed severe stenoses of bilateral VAs. He underwent anticoagulation and wore soft collar. Angiogram 20 days after onset revealed improvement of bilateral VA stenoses. He was discharged with no neurological deficit. It is said that vertebral artery injuries in association with head and neck trauma are relatively rare, but this condition is possible to be more common than realized, considering that the case of unilateral VA occlusion or the case with well developed collateral circulation is sometimes well tolerated for ischemia and that this condition can occur even after mild head and neck injury. The diagnosis must be established by vertebral angiogram, but MRI and MRA are very useful as ancillary methods. The therapeutic point is to prevent propagation of the thrombus and distal embolism, accordingly wearing a collar and anticoagulation are important. 相似文献
899.
B Beauvoit H Liu K Kang PD Kaplan M Miwa B Chance 《Canadian Metallurgical Quarterly》1993,23(1-3):91-109
An understanding of the optical properties of biological media and cells is essential to the development of noninvasive optical studies of tissues. Unicellular organisms offer a unique opportunity to investigate the factors affecting light propagation, since they can be manipulated in ways impossible for more complex biological samples. In this study, we examined optical absorption and scattering properties of strongly multiple scattering yeast suspensions by means of near-infrared (NIR) time-resolved spectroscopy (TRS) and a sample substitution method. We determined the critical parameters for photon migration by varying the cell organelle content, the cell ploidy, the cell size, and the concentration of suspended cells. The results indicate that the photon absorption is insensitive to cell differentiation and that the cell volume is the primary factor determining light-scattering property. 相似文献
900.
H Kawamoto S Hasegawa S Sawatari C Miwa O Morita T Hosokawa H Tanaka 《Canadian Metallurgical Quarterly》1993,37(12):991-997
Two outbreaks of non-bacterial gastroenteritis occurred in Gifu prefecture in January 1989 and in January 1991. Both outbreaks were closely related to the consumption of raw oysters, and showed similar clinical features. Small, round-structured virus particles were found in patient stools in both outbreaks by electron microscopy. The role of these particles as the causative agents of the outbreaks were strongly suggested by immune electron microscopy and/or western-blotting immunoassay. When compared with SRSV-9 (Tokyo/SRSV/86-510) reported previously (Hayashi et al, J. Clin. Microbiol., 27: 1728-1733, 1989), it was found that these viral particles were antigenically similar to SRSV-9, and had a major structural protein of 63 kilodaltons (kDa). Further, the prevalence of this agent in Gifu area was examined by western blot antibody assay using 67 serum samples collected from the inhabitants in 1991. The results indicated the circulation of the same or antigenically similar agent in this area. 相似文献