全文获取类型
收费全文 | 914篇 |
免费 | 3篇 |
专业分类
电工技术 | 21篇 |
化学工业 | 82篇 |
金属工艺 | 24篇 |
机械仪表 | 63篇 |
建筑科学 | 4篇 |
矿业工程 | 3篇 |
能源动力 | 6篇 |
轻工业 | 2篇 |
水利工程 | 16篇 |
石油天然气 | 55篇 |
无线电 | 60篇 |
一般工业技术 | 230篇 |
冶金工业 | 222篇 |
原子能技术 | 77篇 |
自动化技术 | 52篇 |
出版年
2021年 | 9篇 |
2020年 | 6篇 |
2019年 | 17篇 |
2018年 | 17篇 |
2017年 | 16篇 |
2016年 | 31篇 |
2015年 | 10篇 |
2014年 | 23篇 |
2013年 | 31篇 |
2012年 | 19篇 |
2011年 | 23篇 |
2010年 | 18篇 |
2009年 | 24篇 |
2008年 | 21篇 |
2007年 | 25篇 |
2006年 | 29篇 |
2005年 | 18篇 |
2004年 | 18篇 |
2003年 | 22篇 |
2002年 | 17篇 |
2001年 | 22篇 |
2000年 | 19篇 |
1999年 | 13篇 |
1998年 | 49篇 |
1997年 | 39篇 |
1996年 | 25篇 |
1995年 | 22篇 |
1994年 | 18篇 |
1993年 | 17篇 |
1991年 | 12篇 |
1989年 | 6篇 |
1988年 | 9篇 |
1986年 | 6篇 |
1985年 | 7篇 |
1984年 | 10篇 |
1983年 | 7篇 |
1981年 | 12篇 |
1980年 | 11篇 |
1979年 | 13篇 |
1978年 | 12篇 |
1977年 | 24篇 |
1976年 | 41篇 |
1975年 | 18篇 |
1974年 | 12篇 |
1973年 | 13篇 |
1972年 | 8篇 |
1971年 | 11篇 |
1970年 | 7篇 |
1968年 | 6篇 |
1966年 | 9篇 |
排序方式: 共有917条查询结果,搜索用时 453 毫秒
1.
2.
Albul V. I. Bychkov V. B. Gusev K. E. Demidov V. S. Demidova E. V. Kurchanov A. F. Luk'yashin V. E. Sokolov A. Yu. 《Measurement Techniques》2003,46(8):810-814
A monitor is proposed based on ultrasonic production when ionizing radiation passes through a medium. The recording element is a 0.2 mm aluminum plate mounted in a ceramic acoustic converter AC in the form of a wedge of thickness 2 mm. The low plate thickness minimizes the beam parameter distortion, while special technology used in the AC provides high sensitivity. The device has been calibrated in the proton beam from the ITEP accelerator at 200 MeV with 2·109–6·1010 particles in a pulse and a pulse length of 70 nsec. 相似文献
3.
J.-P. Han S.M. Koo E.M. Vogel E.P. Gusev C. DEmic C.A. Richter J.S. Suehle 《Microelectronics Reliability》2005,45(5-6):783
Anomalous threshold voltage roll-up behavior, commonly referred as reverse short channel effect (RSCE), has been observed in high-k (HfO2 on SiON buffer, Al2O3 on SiON buffer) gated submicron nMOSFETs, while the SiO2 or SiON control samples show normal short channel effect (SCE) behavior. The possible causes such as inhomogeneous channel doping profile and gate oxide thickness variation near S/D ends have been ruled out. The results indicate that interface trap density that dependents on channel length is the main cause of the RSCE observed here. In addition, oxide charge also plays a role. 相似文献
4.
AA Bakova BD Brondz OA Fedorkina VA Gusev AI Gordienko IuS Krivoshein IuL Krivorutchenko TG Prokopenko IA Popov 《Canadian Metallurgical Quarterly》1994,39(4):187-189
The possibilities of using influenza A (Leningrad) 385/80 (H3N2) virus matrix protein-specific FITC-labeled D8 monoclonal antibodies in immunofluorescence assays were investigated. The virus antigen accumulation was detected in chorioallantoic cells of chick embryos. Exhibiting the type-specific properties, the fluorescent antibodies stain the perinuclear space, cytoplasmic membrane, and granular structures in the cytoplasm of infected cells. The haemagglutination test tires in the corresponding specimens were at least 1:16. 相似文献
5.
OBJECTIVE: To evaluate the discrepancy index between the clinical and histological diagnosis and the prevalence of epithelial dysplasia and carcinoma in 45 patients with potentially malignant epithelial oral lesions (PMEL). PATIENTS AND METHODS: We submitted 45 patients with PMEL to clinical examination and obtained a biopsy from each. The results of histological diagnosis were compared to the clinical diagnosis. RESULTS: Clinical diagnosis showed that the most common PMEL was leukoplakia followed by lichen planus and by actinic cheilitis associated with leukoplakia. The most common site was the buccal mucosa. Histological diagnosis revealed that 46.7% of the PMEL were lichen planus. The discrepancy index between clinical and histological diagnosis was 24.4%. The higher discrepancy index occurred among leukoplakias. The prevalence of epithelial dysplasia and carcinoma was 17.8%. CONCLUSIONS: We conclude that all PMEL should be submitted to a microscopic analysis because the discrepancy between clinical and histological diagnosis was present in a quarter of these lesions. Otherwise, the epithelial dysplasia and carcinoma were more frequent in the leukoplakias. 相似文献
6.
G. M. Gusev X. Kleber U. Gennser D. K. Maude J. C. Portal D. I. Lubyshev P. Basmaji M. de P. A. Silva J. C. Rossi Yu. V. Nastaushev M. R. Baklanov 《Solid-state electronics》1996,40(1-8):441-446
Electron scattering by a single barrier is predicted to reveal singularities as the magnetic field is changed, because the number of electron collisions with the barrier dramatically increases as chaotic orbits around the barrier are changed into periodic orbits. To test this experimentally we have measured the magnetoresistance of AlGaAs/GaAs heterostructures with a two-dimensional electron gas and a lateral lattice containing a macroscopic number of oval-shaped antidots fabricated using electron lithography. Reproducible fluctuations in the magnetoresistance are observed at low field, which are due to the oscillations of the number of electron collisions with the antidots. The number of collisions N before the electron escapes from the antidot has been calculated as a function of B in an electric field. The position of the maxima in N(B) obtained from calculations and experiment are in reasonable agreement. 相似文献
7.
8.
Translated from Khimicheskoe i Neftyanoe Mashinostroenie, No. 3, pp. 20–22, March, 1991. 相似文献
9.
IuA Magakian EM Karalova LO Abroian SA Karapetian 《Canadian Metallurgical Quarterly》1997,39(8):705-710
Cytophotometry of rat blood erythroid cells during anaemia, induced by phenylhydrazin (4-8 days from the beginning of injections), revealed that all forms of bone marrow containing haemoglobin were thrown into the blood. On its peak (4th day), the greatest contribution in blood haemoglobinization (50%) is made by microcytes. From the 5th day and up to the end of the restoration period the important role in this process is played by macrocytes. From the 6th day the role of normocytes increases, whose contribution by 8th day reaches 70% of the whole haemoglobin amount in blood. In contrary to anaemizated birds, whose erythroid cells ripen in blood, in rats all the transformations of erythron during anaemia are accomplished in bone marrow. 相似文献
10.
VA Khil'ko VR Gofman AT Grechko LA Glaznikov IuA Shulev 《Canadian Metallurgical Quarterly》1997,(3):35-37
This paper presents the information on the early period of an explosive head trauma and trauma to the auditory system. Different types of hearing impairment, the staging of the pathological process were determined along with various immunological and biochemical changes occurring in this group of patients. The results of the study call for necessity of the early ENT observation of all patients in whom an explosive trauma is suspected. 相似文献