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991.
P.G. Ranjith S.K. Choi M. Fourar 《International Journal of Rock Mechanics and Mining Sciences》2006,43(2):216-223
An experimental study using a triaxial apparatus was used to analyze the two-phase flow patterns in jointed rock specimens. Rock specimens having a single natural fracture were tested for two-phase flow of water and air. Triaxial tests were conducted to characterize the two-phase flow through fractured granite specimens at low confining pressures. It was found that for a relatively smooth joint (JRC<6), bubble flow pattern occurred within the rock joint when the gas velocity is below 15 m/s. The average velocity of water usually varied between 0.1 and 0.5 m/s for bubble flow patterns. In this velocity range, air bubbles were able to form along the joint walls or to be randomly displaced within the water phase. When the gas velocity inside the rock joint exceeded 22 m/s, the flow patterns took annular form for non-zero capillary pressures (i.e., injected gas pressure is not equal to injected water pressure). At elevated (>0.25 MPa) gas injection pressures, the gas occupied the main part of the fracture and the liquid was able to flow as an unstable film forming an annular flow along the joint. When the annular flow developed, the mixture flow pattern was independent of the air flow velocity. This was due to the fact that once the injected air velocity reached a critical value (i.e., 20 m/s), water velocity inside the joint was negligible for a given confining pressure and injected water pressure. Further increase in inlet air pressures developed a single-phase air flow with no water flow. 相似文献
992.
Jiun-Haw Lee Xinyu Zhu Yi-Hsin Lin Wing Kit Choi Tien-Chun Lin Sheng-Chih Hsu Hoang-Yan Lin Shin-Tson Wu 公伟刚 朱正龙 周立 《现代显示》2006,(10):30-36
一种高环境对比度(A-CR)和大开口率的显示器已经从理论上证明,并通过把一个正常显黑反射型显示器(NB-RLCD)和一个有机电致发光器件(OLED)堆垛的实验加以证明。这种前后双置(以下称为tandem型)的器件组合可以分别在明亮或昏暗的环境下切换NB-RLCD模式或OLED模式。RLCD的正常显黑特性也可以提升OLED模式工作时的A-CR性能。为了在RLCD模式下获得更好的图像品质,一个复杂并且具有传输功能的结构被用于消除镜面反射和提高可视角至CR﹥2:1超过55°的锥面可视角度。另外,这样的结构也可以提高OLED49.4%的表面量子效率。在我们的实验里,忽略环境亮度因素并使A-CR保持在100:1以上。 相似文献
993.
The field emission characteristics of an oxidized porous polysilicon (OPPS) were investigated with a Pt/Ti multilayer electrode,
which showed highly efficient and stable electron emission characteristics compared with those of conventional Au/NiCr electrodes.
The thin Ti layer played an important role in promoting the adhesion of Pt to SiO2 surface and the distribution of the electric field on the OPPS surface. Additionally, the Ti layer efficiently blocked the
diffusion of emitter metal, which resulted in more reliable emission characteristics. 相似文献
994.
Yi Kai Zhou Sung Woo Choi Shigeya Kimura Shuichi Emura Shigehiko Hasegawa Hajime Asahi 《Journal of Superconductivity and Novel Magnetism》2007,20(6):429-432
GaGdN layers were grown at temperatures below 300°C by radio-frequency plasma-assisted molecular beam epitaxy on sapphire
substrates. GaGdN samples with high Gd concentration as high as 12.5% were obtained by lowering the growth temperature. X-ray
diffraction results showed no obvious secondary phase, which means that the phase separation can be suppressed by the growth
at low temperatures. All samples, including those grown at room temperature, showed ferromagnetic characteristics. Photoluminescence
emission was observed, though spectra exhibit broad and sharp luminescence bands related to many kinds of defects. It is suggested
that electrons coming from defects, especially, nitrogen vacancy, stabilize ferromagnetism, and that the carrier-induced ferromagnetism
occurs in the low-temperature-growth GaGdN. 相似文献
995.
In this paper, we report on the design, fabrication, and test of a passive pressure transensor. The sensor uses the self-resonant frequency modulation of an integrated coil to detect the pressure variations. This modulation is generated by the relative displacement of a ferrite core attached to a silicone rubber membrane. This scheme simplifies the packaging of the passive transensor by removing the requirement for a separate capacitor to form the resonator. A 30-turn 1.7-/spl mu/H coil having dimensions of 3/spl times/3 mm/sup 2/ is used in a prototype design yielding a sensitivity of 9.6 kHz/kPa with a cylindrical ferrite core of 0.95-mm diameter and 0.5-mm height. We also present a theoretical model of the sensor that shows good agreement with the experimental data. This model can be a useful tool for further optimization of the senors. 相似文献
996.
KS Choi JJ Nah CU Choi YJ Ko HJ Sohn G Libeau SY Kang YS Joo 《Canadian Metallurgical Quarterly》2003,96(1):1-16
An experimental competitive enzyme-linked immunosorbent assay (morbillivirus cELISA) using a recombinant N antigen (rRPV N) expressed in a baculovirus and a ruminant morbillivirus (RPV and PPRV)-specific monoclonal antibody (P-13A9) was developed for simultaneous detection of rinderpest virus (RPV) and peste des petits ruminants virus (PPRV) antibodies and its diagnostic performance was evaluated. A set of known reference antisera against RPV and PPRV belonging to different lineages, experimental sera from cattle vaccinated for a RPV of Asian lineage, and field sera from cattle and sheep/goat populations known to be positive (West Africa) and negative (Korea) for RPV and PPRV were used for the evaluation. Morbillivirus cELISA results on the panel of experimental RPV and PPRV antisera showed high correlation (r=0.97) between the whole virus and the rRPV N antigens, suggesting that the rRPV N contains a ruminant morbillivirus-specific antigenic determinant recognized by the P-13A9 and it may be suitable as an ELISA antigen in place of the whole virus. Morbillivirus cELISA detected anti-RPV and anti-PPRV antibodies in all reference RPV and PPRV antisera containing VN titers >/=1:8, suggesting that the assay can simultaneously detect antibodies against RPV and PPRV. Anti-RPV antibody was detected by morbillivirus cELISA in vaccinated cattle as early as the VNT and continued to be detectable by both the cELISA and the VNT until termination of the study. When applied to field samples from Africa, morbillivirus cELISA showed good agreement with a RP cELISA kit (kappa value of 0.86) in bovine sera and with a peste des petits ruminant cELISA kit (kappa value of 0.81) in caprine/ovine sera. Usefulness of morbillivirus cELISA using the rRPV N protein was discussed. 相似文献
997.
Byoung-Ho Choi Alexander Chudnovsky Kalyan Sehanobish 《International Journal of Fracture》2007,145(1):81-88
Stress corrosion cracking (SCC) in engineering thermoplastics is commonly observed in the form of a microcrack colony within
a surface layer of degraded polymer exposed to a combined action of mechanical stresses and chemically aggressive environment.
A probabilistic modeling of SCC initiation is briefly discussed. A deterministic modeling of slow stress corrosion (SC) crack
growth process is developed using Crack Layer (CL) theory. Numerical solution of SC crack growth equations is discussed. Comparison
of the kinetics of cracks driven by SC and by stress only is presented. Conventional plot of SC crack growth rate vs. the
stress intensity factor is constructed and analyzed. An algorithm for conservative estimation of lifetime of engineering thermoplastic
subject to a combination of mechanical stresses and chemically aggressive environment is discussed. 相似文献
998.
999.
Do Haeng Hur Myung Sik Choi Uh Chul Kim Jung Ho Han 《Nuclear Engineering and Design》2003,220(1):916-16
The effect of temperature on magnetite dissolution and corrosion behavior was evaluated in ethylenediaminetetraacetic acid (EDTA)-based solvents for iron oxide chemical cleaning of nuclear steam generators at temperatures ranging from 93 to 150 °C. Magnetite dissolution was drastically accelerated as the temperature was raised to 150 °C, while the amount of corrosion was controlled well within an allowable limit. Periodic venting and excessive EDTA concentration in the solvents were expected to be very effective in dissolving hard tube sheet sludge piles. The linear polarization (LP) method was also suitable to monitor the changes of corrosion rates and process conditions such as venting. 相似文献
1000.
I. Bita T. Choi M. E. Walsh H. I. Smith E. L. Thomas 《Advanced materials (Deerfield Beach, Fla.)》2007,19(10)
A novel method for producing large‐area 3D nanostructured quasicrystalline materials uses 2D multiple exposure lithography to produce an octagonal quasiperiodic surface‐relief template (background image). A replica in polydimethylsiloxane is then used as a phase mask to create 3D bicontinuous axial quasicrystalline SU‐8 epoxy nanostructures (see insets), as reported on p. 1403 by Ion Bita, Edwin Thomas, and co‐workers. 相似文献