全文获取类型
收费全文 | 528篇 |
免费 | 12篇 |
国内免费 | 2篇 |
专业分类
电工技术 | 38篇 |
综合类 | 2篇 |
化学工业 | 155篇 |
金属工艺 | 11篇 |
机械仪表 | 8篇 |
建筑科学 | 7篇 |
矿业工程 | 2篇 |
能源动力 | 15篇 |
轻工业 | 30篇 |
石油天然气 | 1篇 |
武器工业 | 1篇 |
无线电 | 33篇 |
一般工业技术 | 117篇 |
冶金工业 | 86篇 |
原子能技术 | 15篇 |
自动化技术 | 21篇 |
出版年
2023年 | 3篇 |
2022年 | 3篇 |
2021年 | 6篇 |
2019年 | 4篇 |
2018年 | 2篇 |
2017年 | 10篇 |
2016年 | 10篇 |
2015年 | 5篇 |
2014年 | 10篇 |
2013年 | 38篇 |
2012年 | 21篇 |
2011年 | 31篇 |
2010年 | 19篇 |
2009年 | 22篇 |
2008年 | 14篇 |
2007年 | 23篇 |
2006年 | 13篇 |
2005年 | 19篇 |
2004年 | 15篇 |
2003年 | 17篇 |
2002年 | 13篇 |
2001年 | 7篇 |
2000年 | 18篇 |
1999年 | 19篇 |
1998年 | 31篇 |
1997年 | 22篇 |
1996年 | 17篇 |
1995年 | 12篇 |
1994年 | 18篇 |
1993年 | 12篇 |
1992年 | 4篇 |
1991年 | 9篇 |
1990年 | 7篇 |
1989年 | 10篇 |
1988年 | 5篇 |
1986年 | 3篇 |
1985年 | 7篇 |
1984年 | 2篇 |
1983年 | 5篇 |
1982年 | 3篇 |
1981年 | 6篇 |
1980年 | 6篇 |
1979年 | 4篇 |
1978年 | 3篇 |
1977年 | 1篇 |
1976年 | 5篇 |
1975年 | 2篇 |
1974年 | 1篇 |
1972年 | 2篇 |
1966年 | 1篇 |
排序方式: 共有542条查询结果,搜索用时 15 毫秒
61.
Hidenori Yahiro Tatsuya ohuchi Koichi Eguchi Hiromichi Arai 《Journal of Materials Science》1988,23(3):1036-1041
The ionic conduction of oxygen in the ceria-alkaline earth oxide system was investigated as a function of temperature, partial pressure of oxygen and oxide composition, together with its crystal structure, density, and microstructure. Undoped ceria and its solid solution with alkaline earth oxides have a cubic fluorite structure. The ionic conductivity of ceria is greatly enhanced by additions of calcia and strontia, even when they are added in excess of the solubility limit. The conductivities of ceria-calcia and ceria-strontia were much higher than those of calcia-and yttria-stabilized zirconia. Up to the limit of calcia and strontia, the ionic transference number was nearly unity in the temperature range between 600 and 900°C. With an increase in calcia and strontia content, the ionic conductivity was little affected by the presence of a second phase of CaO and SrCeO3. 相似文献
62.
T Yano Y Fukuyama H Yokoyama S Kuninaka Y Terazaki T Uehara H Asoh Y Ichinose 《Canadian Metallurgical Quarterly》1998,14(2):152-155
OBJECTIVE: To determine the distribution and significance of microcalcifications in histologic sections of the prostate. DESIGN: Retrospective review of all histologic slides of completely embedded prostates from surgical specimens. MATERIALS: Randomly selected material included 266 radical prostatectomy and 10 cystoprostatectomy prostates without prostate cancer. Nonrandomly selected specimens included 26 radical prostatectomy specimens with a Gleason pattern 5 component, 24 cases with collagenous micronodules, and 8 cases previously noted to have microcalcifications within foci of prostate cancer. RESULTS: Four patterns of microcalcifications were noted in association with prostate cancer: (1) dystrophic calcification in the comedo-type necrosis of Gleason pattern 5, (2) intraluminal calcification in cribriform-type Gleason pattern 3 prostate cancer, (3) intraluminal calcification in small acinar adenocarcinoma, and (4) stromal calcification within collagenous micronodules associated with prostate cancer. Microcalcifications were noted in 32% of prostates without cancer; 1.9% of randomly selected prostates demonstrated microcalcifications associated with prostate cancer. CONCLUSIONS: Microcalcifications are less common in association with prostate cancer than with benign prostatic ducts and acini. However, intraluminal microcalcifications associated with an atypical small glandular proliferation should not be taken as unequivocal evidence of a benign process. 相似文献
63.
Involvement of superoxide and nitric oxide on airway inflammation and hyperresponsiveness induced by diesel exhaust particles in mice 总被引:1,自引:0,他引:1
HB Lim T Ichinose Y Miyabara H Takano Y Kumagai N Shimojyo JL Devalia M Sagai 《Canadian Metallurgical Quarterly》1998,25(6):635-644
We previously demonstrated that chronic intratracheal instillation of diesel exhaust particles (DEP) induces airway inflammation and hyperresponsiveness in the mouse, and that these effects were partially reversed by the administration of superoxide dismutase (SOD). In the present study, we have investigated the involvement of superoxide in DEP-induced airway response by analyzing the localization and activity of two enzymes: (1) a superoxide producer, NADPH cytochrome P-450 reductase (P-450 reductase), and (2) a superoxide scavenger, SOD, in the lungs of the exposed mice and controls. P-450 reductase was detected mainly in ciliated cells and clara cells: its activity was increased by the repeated intratracheal instillation of DEP. While CuZn-SOD and Mn-SOD were also present in the airway epithelium, their activity was significantly decreased following DEP instillation. Exposure to DEP doubled the level of nitric oxide (NO) in the exhaled air. DEP exposure also increased the level of constitutive NO synthase (cNOS) in the airway epithelium and inducible NO synthase (iNOS) in the macrophages. Pretreatment with N-G-monomethyl L-arginine, a nonspecific inhibitor of NO synthase, significantly reduced the airway hyperresponsiveness induced by DEP. These results indicate that superoxide and NO may each contribute to the airway inflammation and hyperresponsiveness induced by the repeated intratracheal instillation of DEP in mice. 相似文献
64.
F Yanagi T Akasaka S Kozuma K Ichinose K Higashi 《Canadian Metallurgical Quarterly》1998,47(11):1369-1372
Use of a transfusion pump (BP 101, Terumo, Tokyo) makes it feasible to obtain a stable and almost constant ejection volume at a flow rate of 99 ml.min-1, with no untoward effects of the intravenously placed needle and the microfilter located in the circuit. An air sensor ensures that the pump will cease operation immediately and automatically if an air bubble occurrs in the circuit. When a blood bag is conventionally connected to a connecting tube, at the maximum flow rate, one must set up a new blood bag within a few minutes, and in emergency situations with a shortage of hands, this would be unduly troublesome. When 5-7 blood bags (400 ml) is connected to 5-7 parallel connecting tubes, the pump will continuously eject blood approximately to 2000 ml at 99 ml.min-1, without replacing the blood bags. 相似文献
65.
Free malonaldehyde formed in the microsomes prepared from livers of monkey, rat, rabbit, mouse, cow, pig, dog, sheep and horse upon CCl4 oxidation was derivatized by reaction with N-methylhydrazine to form 1-methylpyrazole which was subsequently analyzed by capillary gas chromatography. Among the livers from animals tested, the monkey and rat livers produced the most malonaldehyde upon CCl4 treatment. Horse liver showed the greatest resistance to CCl4 oxidation. The gas chromatography method used in the present study exhibited an accurate and specific measurement of free malonaldehyde that might provide an understanding of the biochemical process of in vitro lipid peroxidation. 相似文献
66.
67.
Hojin Ryu Eiki Kasai Kazumasa Sugiyama Fumio Saito Yoshio Waseda Hiromichi Ohta 《Particulate Science and Technology》1993,11(3):157-164
The present paper describes the effect of grinding a kaolinite/aiuminum-trihydroxide mixture using a planetary ball mill on the structure of the ground product and the mean thermal expansion coefficients of samples sintered from the unground and ground mixtures. The size reduction of the mixture predominates in the early stage of grinding and the obtained fine particles aggregate subsequently with an increase in grinding time. The crystal structure of the mixture is collapsed easily into a disordered one, of which amount increases with an increase in grinding time. Only mullite phase was detected in the sintered body of the ground products at relatively lower temperature 1523K except for anatase as an inherent impurity, whereas corundum, cristobalite and Al-Si spinel phases besides mullite were formed in the sintered body of the unground mixture. The thermal expansion coefficients of sintered bodies of the 120 minutes-ground mixture are considerably lower than those of the unground mixture by about 10%. Consequently, the planetary milling enables us to improve the uniform mixing state at the atomic scale resulting in direct formation of mullite with high purity at relatively low temperature with a lower thermal expansion coefficient of the sintered body. 相似文献
68.
Shoji Suehiro Takeshi Yamada Thein Kyu Ken-Ichi Fujita Takeji Hashimoto Hiromichi Kawai 《Polymer Engineering and Science》1979,19(13):929-939
Dynamic x-ray diffraction is employed to scrutinize the structural origin of the α mechanical dispersion of a highdensity polyethylene having preferentially oriented rownucleated cylindritic texture around the machine direction (MD). Results indicate that the α1 dispersion is associated with two kinds of orientation processes of crystallites: (1) the orientation process involving the rotation of crystallites around the crystal b-axis (lamellar axis) dominates in the MD specimen; (2) the other process accompanying the rotation of crystallites or lamellar segments around their crystal a-axis dominates in the TD (transverse direction) specimen. The complex apparent crystal lattice compliances show no frequency dependence in the real component and no appreciable value in the imaginary component, indicating that the α1 process is definitely associated with the intercrystalline process, but not relavent to the intracrystal process. However, at elevated temperatures, the complex lattice compliances exhibit a remarkable frequency dependence, suggesting that the α2 dispersion concomitant to intracrystalline nature takes place in this time scale. The α2 dispersion was found to be more pronounced upon stretching along the lamellar axis (TD) than normal to it (MD). 相似文献
69.
Ichinose Susumu Matsuki Makoto Higuchi Kazuhito 《Industry Applications, IEEE Transactions on》1985,(1):47-52
A new solid-state scanning ink jet recording technique, called slit jet recording, is proposed. This technique uses a recording head with one slitlike ink-issuing opening having a number of recording electrodes arrayed along a horizontal scanning direction. The ink is emitted from the ink-issuing opening due to the electrical potential difference between a driven recording electrode and a counterelectrode located behind the recording paper. The ink strikes the paper and forms a recording dot. Many recording electrodes can be driven simultaneously by video signals which enhance the total copy recording speed over that for conventional techniques using a single nozzle. The head of this ink jet recording apparatus is remarkably simple in construction and can be fabricated without difficulty. Improvements in reliability and maintainability can also be expected, as the simple structure of the ink-issuing opening reduces clogging and facilitates easy cleaning as compared with other equipment having a large number of nozzles. The recording principle and characteristics and ink-issuing characteristics are described, and the results of a trial recording are presented. The results show that an ISO A4 size (210 mm x 297 mm) full-color copy can be recorded in about 30 s at an 8-dot/ mm rate. 相似文献
70.
A disposable suturing instrument is used in our surgical method for sacrospinous vault suspension to facilitate suture placement and retrieval. The pararectal space is dissected and the suturing device is placed just medial to the lateral third of the sacrospinous ligament-coccygeus muscle complex. Depression of the device's firing button advances a standard needle in a controlled circular path through the sacrospinous ligament-coccygeus muscle complex. The needle is retrieved with a straight-needle holder at a consistent location, 3 mm from the shaft of the instrument. A second suture is placed 0.5-1 cm medial to the first suture. If the holding strength for either suture is considered inadequate, the device is reloaded with the same suture and subsequent bites are taken. The procedure is completed using standard methods. In ten women treated for vaginal vault eversion, lateral dissection was completed in less than 10 minutes, and passage of two sutures through the sacrospinous ligament was accomplished in less than 2 minutes. There were no complications. One patient described mild buttock pain that resolved in 1 week. At 4-6 months' follow-up, vaginal examination with maximal straining demonstrated direct apposition of the vaginal wall to the sacrospinous ligament. 相似文献