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991.
吕林女 《武汉理工大学学报(材料科学英文版)》2009,24(1):140-144
Fly ash (FA) and ground granulated blast-furnace slag (GGBFS) were added to improve the performances of regenerated binding
materials (RBM) which refer to dehydrated phases with rebinding ability of waste hardened cement paste. Flowability tests,
compressive strength tests, SEM, TG-DSC, and non-evaporable water content tests were employed to study the performances of
the combined binding materials and the interactions between RBM, FA, and GGBFS. Results show that adding FA or GGBFS can improve
the workability of RBM paste, and GGBFS has positive effects on strength of RBM. Pozzolanic reactions happen between RBM,
FA, and GGBFS. And the activation effect of RBM to FA and GGBFS is superior to that of P.O grade-32.5 cement, especially at
earlier ages, because of the high reactive f-CaO existing in RBM. On the advantages of the synergetic effects of RBM and pozzolanic admixtures such as FA and GGBFS, new
combined binding materials can be prepared by blending them together.
Funded by the National Science Foundation of China(No. 50508034) 相似文献
992.
何庆复 《武汉理工大学学报(材料科学英文版)》2009,24(3):428-431
Behaviour of hardening and serration yield of a Fe-Ni-Cr alloy under isothermal cycling (ISC) and out-phase TMF was studied
on the basis of varied hysteresis loops. Cycling hardening and serrated yielding for ISC depend on the temperature and the
total strain range, stronger hardening with serrated yielding at higher strain range under ISC at 600 °C, but no hardening
and serrated yielding occurred under ISC at 800 °C. Stronger hardening with stress serration occurred at the thermal path
going to the lowest temperature, no stress serration occurred at the highest temperature under the out-phase. The hardening
also depends on the total strain range, higher total strain range with lower cycling temperature resulted in a stronger hardening
and remarkable serration yielding behavior. Weaker hardening without serrated yielding occurred at near 800 °C may due to
an obvious cycling stress drop under out-phase TMF. Change in the shape of the hysteresis loops also expresses the degree
of the damage of the tested alloy under out-phase and ISC. 相似文献
993.
贺海燕 《武汉理工大学学报(材料科学英文版)》2009,24(3):359-362
Fatigue-free Bi3.2La0.8Ti3O12 ferroelectric thin films were successfully prepared on p-Si (100) substrates using metalorganic solution deposition process. The orientation and formation of 5-layers thin films
were studied under different processing conditions using XRD. Experimental results indicate that increase in annealing time
at 700 °C after preannealing for 10 min at 400 °C can remarkably increase (200)-orientation of the films derived from the
precursor solutions with two contents of citric acid. Meanwhile, high content of citric acid increases the film thickness
and is conducive to the a-orientation of the films with the preannealing, and low concentration of the solution is conducive to the c-orientation of
the films without the preannealing. 相似文献
994.
基于广义AIC和RPC的OFDM航空信道估计算法 总被引:1,自引:0,他引:1
文章通过对航空信道的分析,指出其稀疏信道特征,使用普通算法对此信道进行信道估计会引入高阶矩阵运算,为加快收敛速度、降低实现难度,文中提出了一种利用GAIC(generalized Akaike information criterion)准则和RPC(repeated phase-rotated Chu)训练序列的OFDM航空信道LS(1east squares)估计方法,该方法利用GAIC准则确定信道模型的阶次及抽头位置,为减小信道估计的运算复杂度,引入RPC序列作为训练序列,既满足了LS(least squares)估计,又大大简化了计算复杂度.文章针对具体应用给出文中算法的性能仿真结果,证明了此算法可避免高阶矩阵运算,节约了大量权值可忽略抽头所引入的资源占用和计算量,且显著减小估计误差,可更好跟踪快变的稀疏信道. 相似文献
995.
Corrosion behavior and corrosion products of a low-alloy weathering steel in Qingdao and Wanning 总被引:3,自引:0,他引:3
A newly developed low-alloy weathering steel has been exposed in two coastal sites (Qingdao in the north,Wanning in the south) in China for one year.The samples in Wanning corroded far more seriously than those in Qingdao.The rust layer formed on the steel was analyzed by X-ray diffraction (XRD),scanning electron microscopy (SEM),N2 adsorption approach,polarization curves,and electrochemical impedance spectroscopy (EIS).The rust formed in Qingdao contains more X-ray amorphous compounds and is more compact than that formed in Wanning.Cr and Cu are enriched in the rust layer near the steel matrix,and the phenome-non is more obvious in Qingdao than in Wanning.The rust layer formed in Qingdao suppresses the anodic and cathodic reaction more remarkably than that formed in Wanning does.The rust layer formed in Qingdao possesses a higher ability to block the per-meation of chloride ions than that formed in Wanning does. 相似文献
996.
K.C. Mills 《北京科技大学学报(英文版)》2009,16(3):261-264
Crystallization properties play an important role in keeping a smooth running of continuous casting process and high sur-face quality of cast strands. To reduce fluorine pollution in slag, a new type of CaO-SiO2-Na2O (CSN) based mold flux was studied. The solidification and crystallization properties, including crystallization temperature, crystallization ratio and solidification minera-graphy, were measured, which were compared with the CaO-SiO2-CaF2 (GF) mold flux. The results show that the crystallization performance is equal to the high fluoride mold powder and CSN can be used for peritectic steel grades sensitive to longitudinal cracking in continuous casting. 相似文献
997.
C/C-SiC composites with SiC island distribution were prepared via a new processing route. The fabrication process mainly included
silicon infiltration by ultrasonic vibration, chemical vapor deposition (CVD), siliconizing, liquid phase impregnation and
carbonization. The wear and friction properties were tested by an MM-1000 wet friction machine. The results show that SiC
phases are mainly distributed between carbon fibers and pyrocarbons as well as among the pryocarbons. The dynamic friction
coefficient of the composites decreases gradually from 0.126 to 0.088 with the increase of the surface pressure from 0.5 to
2.5 MPa at the same rotary speed. Furthermore, under the constant surface pressure, the dynamic friction coefficient increases
from 0.114 to 0.126 with the increase of the rotary speed from 1 500 to 2 500 r/min. However, the coefficient decreases to
0.104 when the rotary speed exceeds 4 500 r/min. During the friction process, the friction coefficient of C/C-SiC composite
is between 0.088 and 0.126, and the wear value is zero after 300 times brake testing.
Foundation item: Project(2006CB600901) supported by the Major State Basic Research and Development Program of China; Project(0991015) supported
by Guangxi Science Found, China; Project(200808MS083) supported by Guangxi Education Department Found 相似文献
998.
Calcium phosphate film was prepared by electrochemical deposition technology. Subsequently, the alkaline treatment process
of calcium phosphate film in 0.1 mol/L NaOH solution was monitored on real time by the piezoelectric quartz crystal impedance
(PQCI) technique. The variations of morphology and composition for the alkaline treatment products were characterized by scanning
electron microscopy (SEM), Fourier transform infrared (FT-IR) and X-ray diffraction (XRD), respectively. The dynamic variations
of calcium phosphate can be characterized by the change of equivalent circuit parameters. The results show that the forming
process of hydroxyapatite (HA) is composed of three stages: (1) acidic calcium phosphate dissolution; (2) phase transformation;
and (3) HA formation. Furthermore, the correlative kinetic equations and parameters are obtained by fitting the static capacitance
(C
s)—time curves.
Foundation item: Project(2005CB623901) supported by the Major State Basic Research and Development Program of China 相似文献
999.
Failure mode and strength anisotropic characteristic of stratified rock mass under uniaxial compressive situation 总被引:1,自引:1,他引:0
A stratified rock mass model was founded by FLAC3D. The failure mode and anisotropic characteristic of strength for stratified rock mass were analyzed. The analysis results
show that the numerical simulation can visually reflect the failure modes of rock samples under different inclination angles
β of structural plane. The stiffness of rock sample before peak strength changes in the compressive procedure. With the increase
of β, the compressive strength σ
c of rock sample decreases firstly and then increases; when β is in the range of 20°–30° and 80°–90°, σ
c has the largest sensitivity to β; while β falls in the range of 30°–70°, σ
c varies little. When ϕ
j
<β<90° (β
j
is friction angle of structure plane), the results obtained from numerical simulation and theoretical analysis are in almost
the same values; while β⩽ ϕ
j
or β=90°, they are in great different values. The results obtained from theoretical analysis are obvious larger than those from
numerical simulation; and the results from numerical simulation can reflect the difference of compressive strength of rock
samples for the two situations of β⩾ ϕ
j
and β=90°, which is in more accordance with the real situation.
Foundation item: Project (50099620) supported by the National Natural Science Foundation of China 相似文献
1000.
以不含抗氧化荆的精炼大豆油为原料,研究了加入蔗糖酯对其氧化稳定性的影响,结果表明:在低温时(烘箱法),HLB13的蔗糖酯具有一定的延缓大豆油氧化的作用,其中0.5‰添加量(质量分数)时延缓氧化效果最好;高温条件下(110℃)HLB13、HLB11、HLB9的蔗糖酯在不同浓度条件下有一定的加速氧化作用. 相似文献