全文获取类型
收费全文 | 592篇 |
免费 | 6篇 |
国内免费 | 13篇 |
专业分类
电工技术 | 69篇 |
综合类 | 1篇 |
化学工业 | 146篇 |
金属工艺 | 24篇 |
机械仪表 | 23篇 |
建筑科学 | 8篇 |
能源动力 | 26篇 |
轻工业 | 38篇 |
水利工程 | 2篇 |
石油天然气 | 1篇 |
无线电 | 62篇 |
一般工业技术 | 91篇 |
冶金工业 | 71篇 |
原子能技术 | 17篇 |
自动化技术 | 32篇 |
出版年
2022年 | 8篇 |
2021年 | 6篇 |
2020年 | 3篇 |
2019年 | 9篇 |
2018年 | 8篇 |
2017年 | 4篇 |
2016年 | 6篇 |
2015年 | 4篇 |
2014年 | 7篇 |
2013年 | 29篇 |
2012年 | 20篇 |
2011年 | 37篇 |
2010年 | 23篇 |
2009年 | 26篇 |
2008年 | 12篇 |
2007年 | 18篇 |
2006年 | 25篇 |
2005年 | 17篇 |
2004年 | 19篇 |
2003年 | 12篇 |
2002年 | 15篇 |
2001年 | 15篇 |
2000年 | 24篇 |
1999年 | 16篇 |
1998年 | 36篇 |
1997年 | 24篇 |
1996年 | 19篇 |
1995年 | 5篇 |
1994年 | 18篇 |
1993年 | 13篇 |
1992年 | 10篇 |
1991年 | 7篇 |
1990年 | 8篇 |
1989年 | 6篇 |
1988年 | 11篇 |
1987年 | 8篇 |
1986年 | 10篇 |
1985年 | 13篇 |
1984年 | 11篇 |
1983年 | 6篇 |
1982年 | 8篇 |
1981年 | 7篇 |
1980年 | 5篇 |
1979年 | 5篇 |
1978年 | 3篇 |
1977年 | 3篇 |
1976年 | 2篇 |
1975年 | 3篇 |
1973年 | 2篇 |
1972年 | 2篇 |
排序方式: 共有611条查询结果,搜索用时 15 毫秒
121.
A Maruyama K Murabayashi M Hayashi H Nakano S Isaji S Uehara T Kusuda S Miyahara A Kondo H Nakano T Yabana 《Canadian Metallurgical Quarterly》1998,28(12):1319-1322
We report herein the unusual case of a 66-year-old woman found to have adenocarcinoma arising in a tailgut cyst. The patient had been observed for 6 months following the discovery of a presacral cystic mass measuring 10 x 9 cm for which she had refused surgery. The serum tumor marker, carcinoembryonic antigen, became slightly elevated, and diagnostic imaging distinctly revealed a tumorous lesion with papillary projection into the cyst lumen. The cystic mass was then excised through the transsacral approach. The pathological findings were compatible with moderately differentiated adenocarcinoma arising in a tailgut cyst. This entity is extremely rare, and only six cases, including our own, have been reported in the English literature. Early complete excision is advised because it is almost impossible to determine for certain whether presacral cystic masses are benign or malignant prior to surgery. 相似文献
122.
Two restriction endonucleases (ENases) were found by screening 38 standard phage strains of Salmonella (S.) Enteritidis. An isoschizomer of SacII ENase that recognizes the sequence 5'-CCGC/GG-3' was identified in S. Enteritidis PT14b, and an isoschizomer of XmaIII ENase (5'-C/GGCCG-3') was found in S. Enteritidis PT16. It is of special interest that the recognition specificities of all known ENases in Salmonella, including those of the S. Enteritidis ENases, are very similar to each other. 相似文献
123.
Goro Isoyama Yoshikazu Miyahara Seiji Asaoka Akira Mikuni Hiroshi Nishimura Kazuo Soda 《Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment》1984,227(3):593-597
A new magnet lattice, named “variable emittance”, for an electron storage ring dedicated to synchrotron radiation is proposed. The lattice has a high flexibility to meet the requirements for a high performance undulator as well as for conventional synchrotron radiation from a bending magnet. Tune shifts due to magnet imperfections were simulated and it is found that the periodic solution of the optics is stable enough except for a very high tune region. The effects of undulators and wigglers on the stored beam were studied and a correction for the tune shift is found necessary for high field wigglers. 相似文献
124.
The "imaging plate" is a highly sensitive image recording plate for X-ray radiography, which is coated with photo-stimulable phosphor. The imaging plate is exposed to electrons in a transmission electron microscope. Its fundamental properties (sensitivity, dynamic range and sharpness) have been estimated in detail. Also, the image quality of the imaging plate for some specimens in a transmission electron microscope has been estimated. As a result, it has been ascertained that the imaging plate has superior properties and high practicability as an image recording material in a transmission electron microscope. 相似文献
125.
126.
Katsunari Oikawa Takuya Ota Yousuke Imano Toshiro Omori Ryosuke Kainuma Kiyohito Ishida 《Journal of Phase Equilibria and Diffusion》2006,27(1):75-82
Phase equilibria and martensitic and magnetic phase transformations of the β phase in the Co−Ni−Ga system have been investigated.
It has been shown that the β phase is in equilibrium with the α-phase over a wide range compositions at 600–1100°C. The β
phase exhibits both a paramagnetic-ferromagnetic transition and a thermoelastic martensitic transition from B2 to L10 structure. The Curie temperature T
C
increases with decreases with decreasing Ni content and with increasing Ga content. The composition region of the β phase
exhibiting the thermoelatstic martensitic transformation from ferromagnetic austenite is located near the α+β two-phase region.
T
C
and M
s
of α+β two-phase alloys increase with increasing annealing temperature.
This paper was presented at the International Symposium on User Aspects of Phase Diagrams, Materials Solutions Conference
and Exposition. Columbus, Ohio, 18–20 October, 2004. 相似文献
127.
In order to solve the problem of the bowing phenomenon in the tentering process of film, the stretching and thermosetting conditions were examined with a poly(ethylene terephthalate) film. The simulated and experimental results confirmed that decreasing or preventing the transmission to the next thermosetting zone of the longitudinal force generated by the transverse stretching, and then restretching the film in the thermosetting zone, effectively reduces the bowing distortion. The following effects were observed: (1) Once the film is cooled after stretching it in a tenter, the different patterns of its deformation behavior can be obtained. The bowing distortion changes remarkably with the temperature of film and the length of the cooling zone. (2) When the temperature of the cooling zone is not higher than the glass transition point, the effect of the cooling zone in reducing the bowing distortion is at its maximum. The longer the cooling zone is, the less the bowing distortion becomes. However, it becomes almost constant when the length of the cooling zone is at least twice the width of the film. (3) When the cooling zone is set up between the stretching and thermosetting zones, the bowing distortion is almost independent of the thermosetting temperature. (4) Relaxation and restretching in the transverse direction in the thermoseting zone influence the bowing distortion: greater relaxation results in greater bowing distortion and greater restretching results in the less bowing distortion. © 1994 John Wiley & Sons, Inc. 相似文献
128.
Shoji Watanabe Tsutomu Fujita Kyoichi Suga Toshiro Yokoyama 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》1975,25(10):733-736
New cyclohexenyl alkenyl ketones are prepared by the reaction of various methyl cyclohexenyl carboxylates and vinylmagnesium chloride; for example, 1-(4′-methyl-3′-cyclohexene-1′-yl)-1-oxo-4-pentene is obtained from methyl 4-methyl-3-cyclohexene-1-carboxylate and vinylmagnesium chloride. 相似文献
129.
130.
Viscoelastic properties of polypropylene melts filled with small (0.15 μm) and large (4.0 μm) CaCO3 particles have been measured. The effects of particle size, loading, and rheological history on the dispersion of particles have been investigated. The dispersion of particles was found to decisively influence the viscoelastic properties of these filled polymers. The systems filled with large particles exhibit a relatively stable viscoelastic behavior. The small particle-filled polymers with low loading are stable similarly to the large particle-filled system. For the system filled with 30 wt% small particles, there appears a “second plateau” in the storage modulus G′ curve in low frequency region and the height of the second plateau depends strongly on the rheological history. The results are interpreted in terms of the formation of an internal structure of particles. It was found that the internal structure of particles is broken up by a steady shear flow and the dispersion of particles is changed. 相似文献