全文获取类型
收费全文 | 46篇 |
免费 | 0篇 |
专业分类
化学工业 | 13篇 |
无线电 | 1篇 |
一般工业技术 | 7篇 |
冶金工业 | 24篇 |
自动化技术 | 1篇 |
出版年
2020年 | 1篇 |
2019年 | 1篇 |
2018年 | 1篇 |
2015年 | 1篇 |
2013年 | 1篇 |
2005年 | 1篇 |
1998年 | 7篇 |
1997年 | 2篇 |
1996年 | 1篇 |
1995年 | 1篇 |
1993年 | 4篇 |
1990年 | 1篇 |
1984年 | 1篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1978年 | 2篇 |
1977年 | 2篇 |
1976年 | 4篇 |
1975年 | 1篇 |
1968年 | 1篇 |
1965年 | 1篇 |
1961年 | 2篇 |
1958年 | 1篇 |
1957年 | 2篇 |
1947年 | 1篇 |
1945年 | 2篇 |
1944年 | 1篇 |
1940年 | 1篇 |
排序方式: 共有46条查询结果,搜索用时 0 毫秒
1.
Alfred C. Marmor Administration for Documentation U.S. Patent Trademark Office William S. Lawson Director Office of Technology Assessment Forecast U.S. Patent Trademark Office John F. Terapane Senior Analyst Office of Technology Assessment Forecast U.S. Patent Trademark Office 《World Patent Information》1979,1(1):15-23
Often overlooked is the wealth of information in patents that makes patents useful to public policy making agencies and corporate management, among others. The source of this information is the bibliographic and classification data associated with each patent. much of which is required by law and hence is extremely accurate. These data serve to fingerprint the increment of technological activity disclosed in a patent. Possible ways of using the data include: — identification of emerging technologies — Monotoring foreign activity — identification of “actors” in the technology — tracking applications and impacts of a technologyThe objective of the technology assessment and forecast program of the United States Patent and Trademark Office is to stimulate the use of the patent file of the Office. The Office of Technology Assessment and Forecast (OTAF), which administers the program has assembled a master data base covering all U.S. patents. It periodically updates this base and adds new data items to it. 相似文献
2.
3.
4.
JB Marmor 《Canadian Metallurgical Quarterly》1998,168(6):540-543
To evaluate the use of high-resolution magnetic resonance imaging (MRI) for the differentiation of skin tumors in the maxillofacial region, 60 patients (25 female) were examined in a 1.5-T whole-body MR imager with a 2.5-cm surface coil. Plain transverse T1-(TR 500 ms, TE 25 ms), T2-(2200 ms, TE 80 ms), fat-(TR 500 ms, TE 28 ms), and water-suppressed (TR 500 ms, TE 38 ms) SE sequences were used. Following the application of the paramagnetic contrast agent Gd-DTPA, transverse T-weighted and fat suppression sequences were repeated. Before and after contrast administration, tumor signal intensities and percent contrast enhancement were determined by a ROI technique. All tumors were classified by standard histologic technique and evaluated with regard to their response to contrast medium. Quantitative evaluation was performed by three independent radiologists. Additionally, signal- and contrast-to-noise ratios were calculated for each tumor type. All MRI findings were compared with histology. Significant contrast enhancement occurred in most tumors; malignant tumors displayed inhomogeneous enhancement. The optimal pulse sequences for tumor delineation are plain T1-weighted, water-suppressed, and contrast-enhanced fat-suppressed sequences. Tumors could not be specified by signal intensities or percent contrast enhancement, and CNR did not allow for malignant lesions to be differentiated from benign tumors. High-resolution MRI proved to be an adequate method for imaging skin tumors and their inner structure. Tumor typing was not possible by either contrast-administration or modification of sequence parameters. In this regard, further innovations in contrast agent design seem to be necessary. 相似文献
5.
PURPOSE: Normal retina is firmly attached to the retinal pigment epithelium, but the force of this adhesion drops precipitously within the first 2-3 min after enucleation. The purpose was to study metabolic factors that might be relevant to this postmortem failure of adhesion. METHODS: Dutch rabbit retina was manually peeled from the retinal pigment epithelium on strips of enucleated eyecup within a 37 degrees C bath. Retinal adhesiveness was measured by observing the amount of retinal pigment epithelium that remained adherent to the retina. RESULTS: Autologous whole blood in place of salt solution retarded the decrease in adhesiveness. A solution of hemoglobin alone was similarly effective, whereas methemoglobin solution failed to help the persistence of retinal adhesion. Bubbling oxygen into the salt solution and circulating it to avoid oxygen depletion at the tissue boundary also proved effective at sustaining retinal adhesiveness. Eyes made ischemic in vivo for 5 min or longer, by elevating intraocular pressure, showed virtually no retinal adhesion when enucleated immediately thereafter. However, eyes made ischemic for 10 min, but allowed to regain circulation for 5 min before enucleation, showed a return of retinal adhesiveness to 80% of normal. CONCLUSIONS: Oxidative metabolism is critical to the maintenance of retinal adhesiveness, and the effects of oxygen deprivation on adhesion are reversible within a certain time period. 相似文献
6.
7.
8.
Fessenden Peter Lee Eric R. Anderson Thomas L. Strohbehn John W. Meyer John L. Samulski Thaddeus V. Marmor Jane B. 《IEEE transactions on bio-medical engineering》1984,(1):126-135
A system employing six planar ultrasound transducers has been utilized for preclinical and pilot clinical studies with the aim of producing therapeutic heating preferentially at depth. The array consists of six 7 cm diameter PZT-4 disks mounted on a spherical shell section with a 26 cm radius of curvature. The crystals operate at different frequencies a few kilohertz above their fundamental frequencies of approximately 350 kHz for near-field peak suppression, and each has a few percent modulation to minimize standing wave effects. In water, the system can be focused to produce a high intensity region near the isocenter with a full width half maximum of approximately 1.5 cm in all directions. In attenuating tissue, the high intensity region is closer to the array of transducers by a few centimeters. For heating of realistic tumors at depth, small wedges are used to rotate the transducer axes a few degrees away from the radial direction, yielding a waist rather than a single point where the individual beam central axes come closest to each other. The waist is 3-6 cm in diameter, producing, ideally, ellipsoidal shaped temperature distributions centered deep in perfused tissue. Quantitative power deposition profile mapping, as well as qualitative studies using liquid crystal sheets, have been performed in water phantoms to characterize the system for different transducer orientations. 相似文献
9.
10.