全文获取类型
收费全文 | 834篇 |
免费 | 35篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 45篇 |
综合类 | 1篇 |
化学工业 | 250篇 |
金属工艺 | 30篇 |
机械仪表 | 15篇 |
建筑科学 | 20篇 |
矿业工程 | 1篇 |
能源动力 | 22篇 |
轻工业 | 78篇 |
水利工程 | 4篇 |
石油天然气 | 1篇 |
无线电 | 54篇 |
一般工业技术 | 118篇 |
冶金工业 | 84篇 |
原子能技术 | 16篇 |
自动化技术 | 131篇 |
出版年
2023年 | 8篇 |
2022年 | 4篇 |
2021年 | 15篇 |
2020年 | 11篇 |
2019年 | 19篇 |
2018年 | 21篇 |
2017年 | 19篇 |
2016年 | 20篇 |
2015年 | 16篇 |
2014年 | 25篇 |
2013年 | 45篇 |
2012年 | 35篇 |
2011年 | 63篇 |
2010年 | 48篇 |
2009年 | 40篇 |
2008年 | 43篇 |
2007年 | 39篇 |
2006年 | 41篇 |
2005年 | 16篇 |
2004年 | 33篇 |
2003年 | 31篇 |
2002年 | 30篇 |
2001年 | 11篇 |
2000年 | 15篇 |
1999年 | 14篇 |
1998年 | 49篇 |
1997年 | 25篇 |
1996年 | 21篇 |
1995年 | 10篇 |
1994年 | 13篇 |
1993年 | 15篇 |
1992年 | 12篇 |
1991年 | 10篇 |
1990年 | 6篇 |
1989年 | 6篇 |
1986年 | 7篇 |
1985年 | 3篇 |
1984年 | 1篇 |
1983年 | 4篇 |
1982年 | 4篇 |
1981年 | 3篇 |
1980年 | 1篇 |
1977年 | 6篇 |
1976年 | 1篇 |
1975年 | 1篇 |
1974年 | 3篇 |
1973年 | 3篇 |
1969年 | 1篇 |
1966年 | 1篇 |
1957年 | 1篇 |
排序方式: 共有870条查询结果,搜索用时 31 毫秒
1.
Increasing the reaction temperature of the living cationic polymerization of isobutylene is crucial for industrial production due to the cost of refrigeration. The reaction temperature increase was achieved with an accelerated reaction rate using a flow reaction system. The polymerization conditions, including the flow reactor design, were based on the results of kinetic studies. Utilizing a milli‐scale flow reactor, polyisobutylene, which has a narrow molecular weight distribution, was obtained within a considerably short residence time at a high temperature. Furthermore, it was confirmed that the value of Mw/Mn correlates with the product of the Reynolds number and the angle of collision. 相似文献
2.
The effect of humidity during storage on the crosslinking reactions of isocyanate groups was investigated with attenuated total reflectance Fourier transform infrared spectroscopy with pressure‐sensitive adhesives composed of poly[ethyl acrylate‐co‐(2‐ethylhexyl acrylate)‐co‐(2‐hydroxyethyl methacrylate)] as a base resin and polyisocyanate as a crosslinker. A peak‐resolving analysis of the amide II region revealed four bands. According to an analysis of the Fourier transform infrared spectra of the model compounds, these four bands were assigned to free urethane linkages, hydrogen‐bonded urethane linkages, free urea linkages, and hydrogen‐bonded urea linkages. As expected, storage under humid conditions led to the formation of free and hydrogen‐bonded urea linkages corresponding to the promotion of isocyanate consumption. Peak resolution of the amide II region was found to be a reasonable way of monitoring urethane and urea linkages during crosslinking reactions. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 3039–3045, 2003 相似文献
3.
Masatsune Kato Takaaki Aoki Takashi Noji Yasuhiro Ono Yoji Koike Tomoyuki Hikita Yoshitami Saito 《Journal of Superconductivity and Novel Magnetism》1994,7(1):37-38
We have investigated the relation between the crystal structure and superconductivity in La1.9Bi0.1CuO4+δ , in which the phase separation observed in La2CuO4+δ is suppressed. A phase diagram in theT?δ plane is given for La1.9Bi0.1CuO4+δ with excess oxygen. For very smallδ values, the crystal structure is orthorhombic, and an orthorhombic-tetragonal phase transition occurs markedly atδ ~ 0.03 in the measured temperature range between 13 and 293 K. Superconductivity is observed in the range of 0.04<δ<0.11. This is clear evidence thathigh-T c superconductivity also appears in the tetragonal phase. 相似文献
4.
Hiroshi Ohta Tomoyuki Hirota Abdur Rahim 《The International Journal of Advanced Manufacturing Technology》2007,33(1-2):36-41
This paper analyzes a multi-product production / inventory system where demands for each item arrive according to a Poisson
process and the production time for each product has an Erlang distribution. The paper proposes an optimality condition that
specifies whether each product should be produced make-to-stock or make-to-order. In the event a product should be produced
make-to-stock, an approach for computing the optimal base-stock level is proposed. Numerical examples are given for illustrative
purpose. 相似文献
5.
T Doi S Takemura H Onodera M Ueda M Deguchi R Nakahara N Ichio S Nakanishi N Seto K Yanagida M Kondo 《Canadian Metallurgical Quarterly》1997,46(11):1108-1113
One of the anaphylatoxins, C5a, is known to increase the expression of the complement receptors, CR1 and CR3, on PMNs which play important roles in the phagocytosis. We measured the expression of these receptors before and after the stimulation with C5a and C5a-receptors (C5aR) on PMNs in patients with systemic lupus erythematosus (SLE). PMNs from 16 patients and 11 normal controls were tested. All the patients with SLE were administered with prednisolone orally and were in the inactive stage. The CR1 expression in SLE was significantly weak (p < 0.01) before and after stimulation with 4.55 nM (50 micrograms/ml) of C5a. There was no significant difference of CR3 expression before stimulation. However, after the stimulation with C5a, the increase of CR3 on PMNs from SLE was significantly small (p < 0.01). C5aR on PMNs showed no difference between the two groups. However, the expression of C5aR was significantly suppressed in patients treated with a high dosage of prednisolone (> = 10 mg/day) compared to those with a low dosage of prednisolone (< 10 mg/day). There was no significant difference of CR1 and CR3 expression between these groups. It is concluded that the increase of CR1 and CR3 on PMNs by C5a in small in SLE, of which impaired increase is not due to C5aR on PMNs, and that the expression of C5aR is suppressed by prednisolone. 相似文献
6.
Thi Thi Nge Makiko Yamaguchi Naruhito Hori Akio Takemura Hirokuni Ono 《应用聚合物科学杂志》2002,83(5):1025-1035
Polyelectrolyte complex based on chitosan and acrylic acid monomer by photoinitiated free‐radical polymerization in the absence of crosslinker showed a large transition in swelling in response to changes in pH of surrounding medium. Their ability to swell arises from polyelectrolyte interactions and molecular structure of the complex. The main properties of interest that related to the molecular structure, swelling volumes, glass transition temperature, and elastic modulus of the complex were investigated. The effect of water content, the only variable in the sample component, played an important role in molecular structure of the complex and as a consequence, the extent of intermolecular linkage, especially amide bonds which in turn governed the degree of swelling of the polyelectrolyte complex in this study. The decreased degree of swelling and higher temperature shift of glass transition temperature was found with increased water content, whereas increased modulus of elasticity of dry complex was found in lower water content of synthesis component. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 1025–1035, 2002 相似文献
7.
Cardiac arrest occurred in a male Labrador Retriever dog weighing 27.8 kg during induction to anesthesia. Immediately after the failure of resuscitation by the external cardiac compression, thoracotomy was performed and open chest direct current (DC) counter shocks were applied with routine emergency medications. Then the dog recovered consciousness. Although cardiac rhythm just after resuscitation was sinus tachycardia with paroxysmal supraventricular tachycardia, multifocal ventricular arrhythmia occurred 2 hr after resuscitation. This arrhythmia might be the result from reversible cardiac lesions due to DC counter shock. 相似文献
8.
Tomoyuki Koga Shinya Kingetsu Nobuyuki Higashi 《International journal of molecular sciences》2021,22(9)
Self-assembly of artificial peptides has been widely studied for constructing nanostructured materials, with numerous potential applications in the nanobiotechnology field. Herein, we report the synthesis and hierarchical self-assembly of collagen-mimetic peptides (CMPs) bearing various aromatic groups at the N-termini, including 2-naphthyl, 1-naphtyl, anthracenyl, and pyrenyl groups, into nanofibers. The CMPs (R-(GPO)n: n > 4) formed a triple helix structure in water at 4 °C, as confirmed via CD analyses, and their conformations were more stable with increasing hydrophobicity of the terminal aromatic group and peptide chain length. The resulting pre-organized triple helical CMPs showed diverse self-assembly into highly ordered nanofibers, reflecting their slight differences in hydrophobic/hydrophilic balance and configuration of aromatic templates. TEM analysis demonstrated that 2Np-CMPn (n = 6 and 7) and Py-CMP6 provided well-developed natural collagen-like nanofibers and An-CMPn (n = 5–7) self-assembled into rod-like micelle fibers. On the other hand, 2Np-CMP5 and 1Np-CMP6 were unable to form nanofibers under the same conditions. Furthermore, the Py-CMP6 nanofiber was found to encapsulate a guest hydrophobic molecule, Nile red, and exhibited unique emission behavior based on the specific nanostructure. In addition to the ability of CMPs to bind small molecules, their controlled self-assembly enables their versatile utilization in drug delivery and wavelength-conversion nanomaterials. 相似文献
9.
Effects of magnetic field and hydrostatic pressure on martensitic transformations in some ferrous and nonferrous alloys have
been studied. The studies clarified the effects of magnetic field and hydrostatic pressure on martensitic transformation start
temperature, magnetoelastic martensitic transformation, morphology of martensites and transformation kinetics of athermal
and isothermal transformations. That is, transformation start temperatures of all the ferrous alloys examined increase with
increasing magnetic field, but those of non-ferrous, such as Ti-Ni and Cu-Al-Ni shape memory alloys, are not affected. On
the other hand, transformation start temperature decreases with increasing hydrostatic pressure in some ferrous alloys, but
increases in Cu-Al-Ni alloys. The magnetic field and hydrostatic pressure dependences of the martensitic start temperature
are in good agreement with those calculated by the equations proposed by our group. In the work on the Fe-Ni-Co-Ti alloy,
we found that magnetoelastic martensitic transformation appear. In addition, several martensite plates grow nearly parallel
to the direction of applied magnetic field in the specimen of an Fe-Ni alloy single crystal. Moreover, we found that the isothermal
process in an Fe-Ni-Mn alloy changes to the athermal one under magnetic field and the athermal process changes to the isothermal
one under hydrostatic pressure. Based on the facts, a phenomenological theory is constructed, which unifies the two transformation
processes. 相似文献
10.
Nobuhiro Iwasa Tomoyuki Mayanagi Noriaki Ogawa Kentaro Sakata Nobutsune Takezawa 《Catalysis Letters》1998,54(3):119-123
Pd and Pt supported on ZnO, Ga2O3 and In2O3 exhibit high catalytic performance for the steam reforming of methanol, CH3OH+H2OCO2+3HH2, and the dehydrogenation of methanol to HCOOCH3, 2CH3OHHCOOCH3+2HH2. Combined results with temperature-programmed reduction (TPR) and XRD method revealed that Pd–Zn, Pd–Ga, Pd–In, Pt–Zn, Pt–Ga and Pt–In alloys were produced upon reduction. Over the catalysts having the alloy phase, the reactions proceeded selectively, whereas the catalysts having metallic phase exhibited poor selectivities. 相似文献