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991.
Ali Hemmatifar Mohammad Said Saidi Arman Sadeghi Mahdi Sani 《Microfluidics and nanofluidics》2013,14(1-2):265-276
Dielectrophoresis (DEP) is an electrokinetic phenomenon which is used for manipulating micro- and nanoparticles in micron-sized devices with high sensitivity. In recent years, electrode-based DEP by patterning narrow oblique electrodes in microchannels has been used for particle manipulation. In this theoretic study, a microchannel with triangular electrodes is presented and a detailed comparison with oblique electrodes is made. For each shape, the behavior of particles is compared for three different configurations of applied voltages. Electric field, resultant DEP force, and particle trajectories for configurations are computed by means of Rayan native code. The separation efficiency of the two systems is assessed and compared afterward. The results demonstrate higher lateral DEP force, responsible for particle separation, distributed wider across the channel width for triangular shape electrodes in comparison with the oblique ones. The proposed electrode shape also shows the ability of particle separation by attracting negative DEP particles to or propelling them from the flow centerline, according to the configuration of applied voltages. A major deficiency of the oblique electrodes, which is the streamwise variation of the lateral DEP force direction near the electrodes, is also eliminated in the proposed electrode shape. In addition, with a proper voltages configuration, the triangular electrodes require lower voltages for particle focusing in comparison with the oblique ones. 相似文献
992.
Davood Iranshahi Ali Mohammad Bahmanpour Ehsan Pourazadi Mohammad Reza Rahimpour 《加拿大化工杂志》2012,90(5):1102-1111
In this study, the operating conditions of an axial flow spherical reactor have been optimised using a reliable optimisation technique and the results are compared with the results of non‐optimised conditions. The dynamic behaviour of the reactor has been considered in the optimisation process and orthogonal collocation method has been used in order to solve the obtained equations from mathematical modelling of the process. The goal of this study is to maximise the aromatics and hydrogen production rate. Therefore, the objective function is the combination of two terms which include the production rate of the mentioned components. The catalyst distribution for each reactor, the inlet pressure of the system, Length per radius for each reactor, the naphtha feed molar flow rate and the hydrogen mole fraction in the recycle stream as well as the inlet temperature of each reactor have been optimised in this study. © 2011 Canadian Society for Chemical Engineering 相似文献
993.
994.
Ganjefar Soheil Afshar Mohammad Sarajchi Mohammad Hadi Shao Zhufeng 《International Journal of Control, Automation and Systems》2018,16(5):2405-2420
International Journal of Control, Automation and Systems - In this study, a new controller method based on wavelet neural adaptive proportional plus conventional integral-derivative (WNAP+ID)... 相似文献
995.
Mohammad Hossein Aboonasr Shiraz Mehran Rezaei Fereshteh Meshkani 《Korean Journal of Chemical Engineering》2016,33(12):3359-3366
Mesoporous nanocrystalline nickel-alumina promoted catalysts with high surface area were prepared by microemulsion (ME) method and employed in dry reforming of methane reaction. The catalysts were characterized by X-ray diffraction (XRD), Brunauer-Emmett-Teller surface area analysis (BET), temperature programmed reduction (TPR) and temperature programmed oxidation (TPO) techniques. The results showed that the prepared catalysts had high porosity with great surface area and small crystallite size. Among the K2O, MgO, CaO and BaO promoters, the MgO promoter showed considerable effect on catalytic performance and coke suppression of catalyst. 相似文献
996.
Annealed ZnO thin film at 400 °C for two hours was deposited on a glass substrate by using pulsed laser deposition (PLD). The structural properties of the annealed ZnO thin film were studied by XRD, TEM and SEM. Gas sensing properties for different gases such as H2 and LPG were investigated. Applying XRD the size of the nanocrystals is found to be 10.61 nm. SEM of the thin film consisted of many grains distributed uniformly throughout the surface. An annealed ZnO thin film sensor showed the typical n-type semiconducting behavior in the case of H2 and LGP gases at low and high operating temperature range, respectively. When working at 50 and 140 °C the sensor exhibits very good dynamic response–recovery characteristics to H2 and LGP, respectively. These results along with a simple fabrication process demonstrate that the annealed ZnO thin film at 400 °C for two hours is promising for developing low cost and high performance H2 and LPG sensors. The low cost of the sensor element fabrication, high H2 and LPG sensitivity, fast response and quick recovery make the entire fabrication process a front-runner and cost-effective for the production of annealed ZnO thin film H2 and LPG sensors. 相似文献
997.
Construction of mechanically stabilized earth (MSE) walls in multi-tiered configurations is a promising solution for increasing the height of such walls. The good performance of this type of walls after recent major earthquakes was reported in a number of technical studies. In the present study, an experimental approach was adopted to compare the seismic performance of single-tiered and multi-tiered MSE walls using physical modeling and through conducting a series of uniaxial shaking table tests. To do so, several geogrid-reinforced soil walls with wrap-around facing (i.e., three-, two-, and single-tiered) with a total height of 10 m were designed in the form of prototypes of 1-m-height wall models. The step-wise intensified sinusoidal waves were applied to the models in 14 typical forms. Comparing the shaking table test results confirmed the post-earthquake advantages of multi-tiered MSE walls. The results revealed that tiered walls exhibited better behaviors under earthquake loading in terms of the seismic stability of the wall, displacement of the wall crest, horizontal displacement of the wall facing, deformation mode and failure mechanism of the wall, settlement of backfill surface, and seismic acceleration responses. 相似文献
998.
999.
Mohammad Taraz Mohammad‐Reza Khatami Maryam Hajiseyedjavadi Amir Farrokhian Mohsen Amini Hossein Khalili Alireza Abdollahi Simin Dashti‐Khavidaki 《Hemodialysis international. International Symposium on Home Hemodialysis》2013,17(3):382-390
Elevated proinflammatory cytokines have been attributed to poor sleep quality in patients receiving hemodialysis. This is the first investigation about the relationship between sleep quality and circulating levels of antiinflammatory markers in these patients. A total of 72 patients who were receiving maintenance hemodialysis were enrolled in this cross‐sectional study. The Pittsburgh Sleep Quality Index (PSQI) was used to measure sleep quality. Patients were divided into two groups: good sleepers (PSQI score < 5) and poor sleepers (PSQI score ≥ 5). Assessments were made for serum biochemical parameters (albumin, parathyroid hormone), inflammatory (interleukin [IL]‐6, tumor necrosis factor‐alpha [TNF‐α], and high‐sensitivity c‐reactive protein [hs‐CRP] ) and antiinflammatory (IL‐10) markers. Fifty‐four patients (75%) were classified as poor sleepers. Poor sleepers showed significantly lower levels of serum IL‐10 and higher serum triglyceride and parathyroid hormone concentrations. These patients were more likely to have more comorbidities. The global PSQI score was significantly correlated with serum IL‐10 (p = 0.03) and triglyceride levels (p = 0.01). Multivariate logistic regression analysis showed a direct correlation between PSQI and having comorbidities (p = 0.011, odds ratio [OR] = 3.918; confidence interval 95% [CI] = 2.742–19.031), between PSQI and serum triglyceride (p = 0.027, OR = 1.027 [95% CI = 1.007–1.048] ), and an inverse correlation between PSQI and serum IL‐10 level (p = 0.021, OR = 0.424 [95% CI = 0.195–0.922]). Reduced circulating levels of the antiinflammatory cytokine IL‐10 were significantly associated with poor sleep quality in hemodialysis patients. Factors including serum IL‐10 and triglyceride concentrations and having comorbidities may predict patients prone to poor sleep quality. 相似文献
1000.
Mujtahid Kaavessina Ilias Ali Rabeh H. Elleithy S. M. Al-Zahrani 《Journal of Polymer Research》2012,19(2):9818-12
Differential Scanning Calorimetry (DSC) was used to evaluate the crystallization behavior of poly(lactic acid) and its blends
with elastomer. It has been observed that the cold crystallization temperature of the blends decreased as the weight fraction
of elastomer increased as well as the onset temperature of cold crystallization also shifted to lower temperature. In non-isothermal
crystallization experiments, the crystallinity of poly(lactic acid) increased with a decrease in the heating and cooling rate.
The melt crystallization of poly(lactic acid) appeared in the low cooling rate (1, 5 and 7.5 °C/min). The presence of low
elastomer tends also to increase the crystallinity of poly (lactic acid). The DSC thermogram at ramp of 10 °C/min showed the
maximum crystallinity of poly(lactic acid) is 36.95% with 20 wt% elastomer contents in blends. In isothermal crystallization,
the cold crystallization rate increased with increasing crystallization temperature in the blends. The Avrami analysis showed
that the cold crystallization was in two stages process and it was clearly seen at low temperature. The Avrami exponent (n)
at first stage was varying from 1.59 to 2 which described a one-dimensional crystallization growth with homogeneous nucleation,
whereas at second stage was varying from 2.09 to 2.71 which described the transitional mechanism to three dimensional crystallization
growth with heterogeneous nucleation mechanism. The equilibrium melting point of poly(lactic acid) was also evaluated at 176 °C. 相似文献