全文获取类型
收费全文 | 890篇 |
免费 | 22篇 |
国内免费 | 7篇 |
专业分类
电工技术 | 50篇 |
综合类 | 4篇 |
化学工业 | 260篇 |
金属工艺 | 34篇 |
机械仪表 | 28篇 |
建筑科学 | 20篇 |
矿业工程 | 1篇 |
能源动力 | 47篇 |
轻工业 | 77篇 |
无线电 | 50篇 |
一般工业技术 | 160篇 |
冶金工业 | 31篇 |
原子能技术 | 55篇 |
自动化技术 | 102篇 |
出版年
2022年 | 4篇 |
2021年 | 9篇 |
2019年 | 9篇 |
2018年 | 16篇 |
2017年 | 10篇 |
2016年 | 14篇 |
2015年 | 15篇 |
2014年 | 13篇 |
2013年 | 50篇 |
2012年 | 40篇 |
2011年 | 64篇 |
2010年 | 29篇 |
2009年 | 33篇 |
2008年 | 42篇 |
2007年 | 35篇 |
2006年 | 44篇 |
2005年 | 40篇 |
2004年 | 28篇 |
2003年 | 29篇 |
2002年 | 25篇 |
2001年 | 19篇 |
2000年 | 18篇 |
1999年 | 29篇 |
1998年 | 14篇 |
1997年 | 19篇 |
1996年 | 17篇 |
1995年 | 13篇 |
1994年 | 17篇 |
1993年 | 12篇 |
1992年 | 7篇 |
1991年 | 19篇 |
1990年 | 9篇 |
1989年 | 9篇 |
1988年 | 4篇 |
1987年 | 12篇 |
1986年 | 18篇 |
1985年 | 13篇 |
1984年 | 20篇 |
1983年 | 11篇 |
1982年 | 12篇 |
1981年 | 11篇 |
1980年 | 6篇 |
1979年 | 16篇 |
1978年 | 13篇 |
1977年 | 9篇 |
1976年 | 7篇 |
1975年 | 2篇 |
1974年 | 2篇 |
1973年 | 2篇 |
1967年 | 2篇 |
排序方式: 共有919条查询结果,搜索用时 15 毫秒
71.
Hisaaki Yagi Fumi Ninomiya Masahiro Funabashi Masao Kunioka 《International journal of molecular sciences》2009,10(9):3824-3835
Anaerobic biodegradation tests of poly(lactic acid) (PLA) powder were done at the thermophilic (55 °C) and mesophilic temperature (35 °C) under aquatic conditions [total solid concentrations of the used sludge were 2.07% (at 55 °C) and 2.24% (at 35 °C)] using a newly developed evaluation system. With this system, the evolved biogas is collected in a gas sampling bag at atmospheric pressure. This method is more convenient than using a pressure transducer or inverted graduated cylinder submerged in water. PLA was degraded about 60% in 30 days, about 80% in 40 days and about 90% in 60 days at 55 °C. On the other hand, the PLA degradation started in 55 days at 35 °C and degradation rate was much slower than at 55 °C. 相似文献
72.
73.
Yuko Hamabe Ryoko Matsuura Akinori Jyo Masao Tamada Akio Katakai 《Reactive and Functional Polymers》2009,69(1):1-8
Bifunctional fibers containing phosphonate and sulfonate were derived from chloromethylstyrene grafted polyolefin fibers (PPPE-g-CMS) by phosphorylation and subsequent sulfonation reactions. It was clarified that phosphorylation of PPPE-g-CMS by Arbusov reaction is more suitable than one by the reaction with PCl3 in the presence of AlCl3, because the latter damaged fibers and gave phosphinate groups in addition to phosphonate ones. Then, bifunctional fibers containing phosphonate and sulfonate groups were prepared by sulfonation of monofunctional phosphonate fibers obtained via Arbusov reaction with chlorosulfonic acid. The metal ion selectivity of the bifunctional fibers was governed by both phosphonate and sulfonate groups. In addition, bifunctional fibers gave much more excellent kinetic performances in column-mode uptake of Cu(II) than the monofunctional phosphonate fibers and resin. 相似文献
74.
The front steering angle control and its integration with the direct yaw moment control are suggested to enhance the handling performance for heavyduty vehicles based on a 3D vehicle modelThe doublecostf unction LQR methodology (DLQR) which extends the concept and the applicable field of LQR to express the practical requirements more plainly,is proposed to determine the control input value:compensation value of front steering angle in the optimal model A simple autotuning proportion controller is employed in direct yaw moment control to regulate the moment timely The simulation results show that front steering angle control using DLQR,has good ability to achieve the desired steering output in the different running conditionsDLQR is more powerful to balance many factors effectively based on the explicit mathematics expression of the physics of the problem than LQR does 相似文献
75.
76.
77.
Phase relations associated with the aluminum blast furnace: Aluminum oxycarbide melts and Al-C-X (X=Fe,Si) liquid alloys 总被引:2,自引:0,他引:2
Harumi Yokokawa Masao Fujishige Seiichi Ujiie Masayuki Dokiya 《Metallurgical and Materials Transactions B》1987,18(2):433-444
The thermodynamic properties and the phase relations were evaluated and estimated for the Al-O-C, Al-Si-C, and Al-Fe-C systems
which are important to understand the chemical behavior in an aluminum blast furnace. The mixing properties of binary liquid
alloys, including metal-carbon systems, were represented by the Redlich-Kister equation. The properties of liquid Al−C and
Si−C alloys were estimated so as to be consistent with their phase diagrams. The coefficients of Al−Fe and Fe−C liquids were
evaluated from reported values for activity and enthalpy. The extrapolation to the higher order systems was made by Maggianu's
method. The aluminum oxycarbide melt was represented by a subregular solution model. In the Al-O-C system, liquid alloy/oxycarbide
melt equilibria were calculated and compared with earlier experimental results and estimates. Attempts were made to clarify
the volatilization of aluminum oxycarbide melts, and also the carbidation of liquid aluminum alloys. An empirical correlation
between the first terms of the Redlich-Kister equation for the enthalpies and the excess entropies was discussed. 相似文献
78.
Masao Taki 《IEEJ Transactions on Electrical and Electronic Engineering》2016,11(6):683-695
Research works on bioelectromagnetics in Japan are reviewed with a focus on the efforts devoted to the issue of human protection from electromagnetic field (EMF) exposures. History of this issue in Japan is briefly reviewed first for all EMF spectra. Then research works on radiofrequency (RF) EMF are summarized in more detail. The RF studies reviewed are mainly conducted in the framework of research program by the Ministry of Internal Affairs and Communications (MIC) started in 1997. Because of this program, collaborations between biology/medicine and engineering have been promoted. The results consistently show no evidence against the safety of RF‐EMF within the exposure levels of internationally accepted guidelines. © 2016 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc. 相似文献
79.
Ohmori T Morita H Tanaka M Miyauchi K Kasai D Furukawa K Miyashita K Ogawa N Masai E Fukuda M 《Journal of Bioscience and Bioengineering》2011,111(4):437-442
Rhodococcus jostii RHA1 accumulates chlorobenzoates (CBA) during the degradation of polychlorinated biphenyls (PCBs). CBA degradation is considered one of the rate-limiting steps in the complete degradation of PCBs. To reduce the accumulation of CBAs, the upper pathway enzyme genes for PCB degradation of RHA1 were introduced into a CBA-degrading bacterium, Burkholderia sp. NK8. The resulting recombinant strain exhibited no biphenyl 2,3-dioxygenase (BphA) activity encoded by bphAaAbAcAd genes, which encode the large and small subunits of the terminal oxygenase component and the ferredoxin and reductase subunits responsible for electron transfer from NADH to the large subunit. The remaining enzyme genes involved in the transformation of biphenyl to benzoate, bphB2C1D1, which encode dehydrogenase, ring-cleavage dioxygenase and hydrolase, conferred activities to NK8. To obtain the BphA activity of RHA1 in NK8, sets of BphA genes were constructed by combining the bphAaAbAcAd genes of RHA1 and bphA3A4 of Pseudomonas pseudoalcaligenes KF707, encoding the ferredoxin and reductase subunits. Hybrid derivatives of BphA containing the KF707 bphA3 conferred BphA activity to NK8, and a derivative containing the RHA1 bphAaAb and KF707 bphA3A4 genes exhibited the highest BphA activity. A plasmid containing the RHA1 bphAaAb and KF707 bphA3A4 genes plus the RHA1 bphB2C1D1 genes was constructed and introduced into NK8. The resulting recombinant strain efficiently degraded 2-, 3- and 4-chlorobiphenyls with an apparent reduction in CBA accumulation in comparison to the recombinant mutant strain, which had an insertion in the cbeA gene to inactivate CBA dioxygenase. 相似文献
80.
Yuya Tachibana Takuya Maeda Osamu Ito Yasukatsu Maeda Masao Kunioka 《International journal of molecular sciences》2009,10(8):3599-3615
We have developed a mulch sheet made by inflation molding of PLA, Ecoflex® and modified starch, which all have different biodegradabilities. A field test of use as an agricultural mulch sheet for mandarin oranges was carried out over two years. The mechanical properties of the mulch sheet were weakened with time during the field test, but the quality of the mandarin oranges increased, a result of the controlled degradation of the sheet. The most degradable modified starch degraded first, allowing control of the moisture on the soil. Accelerator mass spectroscopy was used for evaluation of the biomass carbon ratio. The biomass carbon ratio decreased by degradation of the biobased materials, PLA and modified starch in the mulch sheet. 相似文献