全文获取类型
收费全文 | 842篇 |
免费 | 29篇 |
国内免费 | 3篇 |
专业分类
电工技术 | 40篇 |
综合类 | 1篇 |
化学工业 | 183篇 |
金属工艺 | 14篇 |
机械仪表 | 25篇 |
建筑科学 | 7篇 |
能源动力 | 39篇 |
轻工业 | 74篇 |
水利工程 | 2篇 |
石油天然气 | 1篇 |
无线电 | 53篇 |
一般工业技术 | 151篇 |
冶金工业 | 173篇 |
原子能技术 | 35篇 |
自动化技术 | 76篇 |
出版年
2023年 | 9篇 |
2022年 | 13篇 |
2021年 | 24篇 |
2020年 | 15篇 |
2019年 | 16篇 |
2018年 | 13篇 |
2017年 | 17篇 |
2016年 | 23篇 |
2015年 | 20篇 |
2014年 | 20篇 |
2013年 | 59篇 |
2012年 | 38篇 |
2011年 | 52篇 |
2010年 | 38篇 |
2009年 | 36篇 |
2008年 | 40篇 |
2007年 | 28篇 |
2006年 | 27篇 |
2005年 | 25篇 |
2004年 | 21篇 |
2003年 | 29篇 |
2002年 | 8篇 |
2001年 | 13篇 |
2000年 | 12篇 |
1999年 | 15篇 |
1998年 | 74篇 |
1997年 | 33篇 |
1996年 | 28篇 |
1995年 | 18篇 |
1994年 | 13篇 |
1993年 | 12篇 |
1992年 | 3篇 |
1991年 | 7篇 |
1990年 | 6篇 |
1989年 | 2篇 |
1988年 | 5篇 |
1987年 | 5篇 |
1986年 | 4篇 |
1985年 | 4篇 |
1983年 | 4篇 |
1980年 | 2篇 |
1978年 | 4篇 |
1977年 | 7篇 |
1976年 | 10篇 |
1975年 | 5篇 |
1973年 | 4篇 |
1972年 | 4篇 |
1971年 | 2篇 |
1970年 | 1篇 |
1968年 | 1篇 |
排序方式: 共有874条查询结果,搜索用时 515 毫秒
51.
Hideki Katagiri Takeshi Uno Kosuke Kato Hiroshi Tsuda Hiroe Tsubaki 《Expert systems with applications》2013,40(2):563-574
This paper considers multiobjective linear programming problems (MOLPP) where random fuzzy variables are contained in objective functions and constraints. A new decision making model optimizing possibilistic value at risk (pVaR) is proposed by incorporating the concept of value at risk (VaR) into possibility theory. It is shown that the original MOLPPs involving random fuzzy variables are transformed into deterministic problems. An interactive algorithm is presented to derive a satisficing solution for a decision maker (DM) from among a set of Pareto optimal solutions. Each Pareto optimal solution that is a candidate of the satisficing solution is exactly obtained by using convex programming techniques. A simple numerical example is provided to show the applicability of the proposed methodology to real-world problems with multiple objectives in uncertain environments. 相似文献
52.
Haruhisa Kato Kohei Mizuno Manabu Shimada Ayako Nakamura Kayori Takahashi Kenji Hata Shinichi Kinugasa 《Carbon》2009,47(15):3434-3440
The slow diffusion of Tween80 surfactant molecules in a single-walled carbon nanotube (SWCNT) aqueous dispersion was directly observed using the pulsed field gradient nuclear magnetic resonance method. The slow diffusion of Tween80 molecules was attributed to the strongly adsorbed molecules on the SWCNTs in the aqueous dispersion. The amount of bound Tween80 molecules was estimated to be approximately 12% of the total amount of Tween80 molecules, contributing to the stability of the SWCNT aqueous dispersion. Using dynamic light scattering and total organic carbon measurements, this SWCNT/Tween80 aqueous dispersion was found to be very stable for at least 3 weeks. The observed zeta potentials of this SWCNT dispersion are between −10 and 0 mV, indicating that the stability of the SWCNTs in the Tween80 solution was maintained by steric interactions between the small amount of adsorbed Tween80 molecules on the SWCNTs, while the effect of electrostatic interactions between adsorbed Tween80 was minimal. This proposed method to investigate the amount of bound Tween80 molecules on SWCNTs has potential benefits in the field of the production of functional materials and nano-toxicity assessments. 相似文献
53.
Our purpose was to determine whether intrauterine sonography with high-frequency, real-time miniature transducer (20 MHz) is useful for the diagnosis of gynecologic disorders. The study consisted of 37 women: 8 normal volunteers, 2 with molar pregnancy, 4 fibromyoma, 4 endometrial polyp, 1 intrauterine adhesion, 1 septate uterus, 5 atypical hyperplasia, 8 endometrial cancer, and 4 with cervical cancer. Comparison of diagnostic efficacy for gynecologic disorders between transvaginal and intrauterine sonography was made. The probe was easily introduced into the endometrial cavity in all patients. No notable complications were encountered. In subjects with a normal uterus, higher resolution for endometrial texture was obtained with intrauterine sonography than with transvaginal scanning. In patients with molar pregnancy, typical vesicular echoes were clearly identified. In patients with fibromyoma, myoma nodules were not clearly visualized because of poor attenuation of ultrasound. In subjects with endometrial polyp, intrauterine adhesion, and septate uterus, intrauterine lesions were clearly identified. In patients with atypical hyperplasia, high echogenicity of the endometrium was characterized. Myometrial invasion of the endometrial cancer was estimated correctly in 6 of 8 patients (75%). Intrauterine sonography could clearly detect early cervical invasion of the cervical cancer in all 4 patients, but transvaginal sonography could not do it. Intrauterine sonography with a high-frequency, real-time miniature transducer might be a useful diagnostic modality in gynecologic disorders, especially in the evaluation of early cervical cancer, endometrial cancer, and possibly in infertility practice. 相似文献
54.
Takachio N. Iwashita K. Hata S. Onodera K. Katsura K. Kikuchi H. 《Microwave Theory and Techniques》1990,38(12):1900-1905
A balanced receiver for multigigabit-per-second coherent optical transmission systems is described. A balanced optical receiver with a frequency bandwidth of 23 GHz is achieved by connecting an InGaAs twin-p-i-n photodiode to a 0.5-30.0 GHz GaAs monolithic distributed amplifier fabricated with a soldier bump flip-chip interconnection technique. An experiment which demonstrated that this receiver has the potential for use in 10-Gb/s optical CPFSK (continuous-phase frequency shift keying) heterodyne detection systems was conducted 相似文献
55.
Kosuke Nagaya Sadahiko Takeda Yoshitaka Nakata 《International journal for numerical methods in engineering》1986,23(6):1081-1099
This paper is concerned with the method for solving the vibration problem of coil springs of arbitrary shape. In the analysis the exact field transfer matrix is derived from the solution of the fundamental equation of the three-dimensional curved beam theory. The transfer matrix is given by combining this field transfer matrix and the point transfer matrix. The analysis derives the frequency equation which is applicable to coil springs of general shape. Numerical calculations have been carried out for hyperboloidal springs and barrel springs. Experimental tests also have been carried out to verify the present results. 相似文献
56.
57.
S. Fujino H. Tokunaga S. Hata E. Saiz A. P. Tomsia 《Journal of Materials Science》2005,40(9-10):2499-2503
A graded glass coating for Vitallium®, a Co-Cr alloy, has been prepared using a simple enameling technique. The composition of the glasses has been tailored to match the thermal expansion of the alloys. The optimum glass composition and firing conditions (temperature and time) needed to fabricate homogeneous coatings with good adhesion to the alloy were determined. The final coating thickness ranged between 25 and 60 μm. Coatings fired under optimum conditions do not delaminate during indentation tests of adhesion. Excellent adhesion to the alloy has been achieved through the formation of 100 nm thick interfacial chromium-oxide (CrOx) layers. The graded glass (consisting of BIG and 6P50 layers) can be successfully coated to a Co-Cr alloy, and forms hydroxyapatite (HA) on the coating surface when immersed in a simulated body fluid (SBF) for 30 days. 相似文献
58.
Katsura K. Hayashi T. Ohira F. Hata S. Iwashita K. 《Lightwave Technology, Journal of》1990,8(9):1323-1327
A flip-chip interconnection technique using small solder bumps instead of conventional wire bonding for high-speed broadband photoreceivers is described. The technique achieves interconnection with low parasitic elements, no damage to devices, and easy assembly. A photoreceiver composed of a broadband p-i-n photodiode and a laser-speed GaAS metal-semiconductor field-effect transistor (MESFET) preamplifier connected using solder bumps that are about 26 μm in diameter, with a frequency response of over 22 GHz at 1.55 μm, is demonstrated. This confirms the effectiveness of the solder bump interconnection technique for future high-speed broadband optical modules 相似文献
59.
Araki T. Nishima H. Hata H. Yamaguchi H. Yamauchi T. Miyashita M. 《Power Delivery, IEEE Transactions on》1998,13(3):718-727
Technologies for the after-laying test of long-distance SF6 gas insulated transmission line (GIL) have been developed for the detection of partial discharge (PD) and contact defects. We constructed a long (168 m) test line in a deep tunnel and clarified the propagation characteristics of PD signals through the GIL as well as the spatial sensitivity and S/N characteristics of PD sensors for locating metallic particles. We have also proposed the application of a fiber-optic temperature distribution sensor for locating contact defects and confirmed the validity of this sensor for the GIL test line 相似文献
60.
Takeshi Kikuchi Makio Mogi Iichiro Okabe Kosuke Okada Hisashi Goto Yasuyuki Sasaki Takeki Fujimura Mitsuo Fukuda Akio Mitani 《International journal of molecular sciences》2015,16(10):24111-24126
Periodontal disease is caused by dental plaque biofilms, and the removal of these biofilms from the root surface of teeth plays a central part in its treatment. The conventional treatment for periodontal disease fails to remove periodontal infection in a subset of cases, such as those with complicated root morphology. Adjunctive antimicrobial photodynamic therapy (aPDT) has been proposed as an additional treatment for this infectious disease. Many periodontal pathogenic bacteria are susceptible to low-power lasers in the presence of dyes, such as methylene blue, toluidine blue O, malachite green, and indocyanine green. aPDT uses these light-activated photosensitizer that is incorporated selectively by bacteria and absorbs a low-power laser/light with an appropriate wavelength to induce singlet oxygen and free radicals, which are toxic to bacteria. While this technique has been evaluated by many clinical studies, some systematic reviews and meta-analyses have reported controversial results about the benefits of aPDT for periodontal treatment. In the light of these previous reports, the aim of this review is to provide comprehensive information about aPDT and help extend knowledge of advanced laser therapy. 相似文献