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861.
本研究分析MRI测量胫骨结节-股骨滑车凹间距(tibial tuberosity-trocholear distance,TT-TG)、髌骨高度(patellar height,PH)、股骨滑车沟角(sulcus angle,SA)、滑车沟深度(sulcus depth,SD),与一次性髌骨外侧脱位(transient lateral patellar dislocation,TLPD)患者诊断及分型的关系。将2018年1月~2019年2月我院收治的50例TLPD患者作为观察组,50例膝关节正常者作为对照组。采用1.5 T MRI测量受试者TT-TG、PH、SA、SD水平,分析各指标单独应用及联合应用的诊断价值,并探讨其与临床分型的关系。结果显示,观察组TT-TG、PH、SA水平均明显高于对照组(P<0.05),观察组SD水平明显低于对照组(P<0.05);TT-TG、PH、SA及SD指标的联合应用可明显提高TLPD诊断的敏感度、特异度及准确度(P<0.05),且联合应用时AUC面积明显大于各指标单独应用,差异存在统计学意义(P<0.05);随着患者Dejour分型恶化,患者TT-TG、PH及SA水平均明显升高,SD水平随之明显降低(P<0.05);TT-TG、PH、SA及SD是影响TLPD患者临床分型的独立性影响因素(P<0.05)。研究结果表明,采用1.5 T MRI对TLPD患者的TT-TG、PH、SA、SD进行测量可有效提高临床诊断价值,且TT-TG、PH、SA、SD是影响患者临床分型的独立性影响因素。 相似文献
862.
Mariavitalia Tiddia Martin P. Seah Alex G. Shard Guido Mula Rasmus Havelund Ian S. Gilmore 《Surface and interface analysis : SIA》2020,52(6):327-334
Secondary ion mass spectrometry studies have been made of the removal of the degraded layer formed on polymeric materials when cleaning focused ion beam (FIB)-sectioned samples comprising both organic and inorganic materials with a 30-keV Ga+ FIB. The degraded layer requires a higher-than-expected Ar gas cluster ion beam (GCIB) dose for its removal, and it is shown that this arises from a significant reduction in the layer sputtering yield compared with that for the undamaged polymer. Stopping and Range of Ions in Matter calculations for many FIB angles of incidence on flat polymer surfaces show the depth of the damage and of the implantation of the Ga+ ions, and these are compared with the measured depth profiles for Ga+-implanted flat polymer surfaces at several angles of incidence using an Ar+ GCIB. The Stopping and Range of Ions in Matter depth and the measured dose give the sputtering yield volume for this damaged and Ga+-implanted layer. These, and literature yield values for Ga+ damaged layers, are combined on a plot showing how the changing sputtering yield is related to the implanted Ga density for several polymer materials. This plot contains data from both the model flat poly(styrene) surfaces and FIB-milled sections showing that these 2 surfaces have the same yield reduction. The results show that the damaged and Ga+-implanted layer's sputtering rate, after FIB sectioning, is 50 to 100 times lower than for undamaged polymers and that it is this reduction in sputtering rate, rather than any development of microtopography, that causes the high Ar+ GCIB dose required for cleaning these organic surfaces. 相似文献
863.
Lu LIN 《数学学报(英文版)》2005,21(3):585-592
In the nonparametric regression models, the original regression estimators including kernel estimator, Fourier series estimator and wavelet estimator are always constructed by the weighted sum of data, and the weights depend only on the distance between the design points and estimation points. As a result these estimators are not robust to the perturbations in data. In order to avoid this problem, a new nonparametric regression model, called the depth-weighted regression model, is introduced and then the depth-weighted wavelet estimation is defined. The new estimation is robust to the perturbations in data, which attains very high breakdown value close to 1/2. On the other hand, some asymptotic behaviours such as asymptotic normality are obtained. Some simulations illustrate that the proposed wavelet estimator is more robust than the original wavelet estimator and, as a price to pay for the robustness, the new method is slightly less efficient than the original method. 相似文献
864.
本文介绍了单形深度函数理论,通过改进夏普指数公式,利用单形深度函数中位数稳健性的特点,将单形深度函数中位数应用于改进的夏普指数公式,对国内的封闭式基金进行了排名与评级,并将其与中信星级和样本星级进行了对比.最后,通过定义基金业绩偏离度提出将其用于评价基金捕捉市场机遇的能力的观点. 相似文献
865.
R. Haakenaasen T. Colin H. Steen L. Trosdahl-Iversen 《Journal of Electronic Materials》2000,29(6):849-852
Ion milling has been used to type convert molecular beam epitaxy vacancy-doped CdxHg1−xTe, and electron beam induced current measurements have been performed to study the pn-junction depth dependence on milling
time, milling current and vacancy concentration. The junction depth seems to initially increase linearly with time for depths
up to ∼ 4 μm, then possibly as the square root of time at larger depth. For given x, the depth increases with decreasing vacancy
concentration. For the same annealing temperature, high x samples have lower carrier concentration and greater junction depth
than low x samples. Up to 4 μm, junction depth is proportional to milling current density as well as milling time. 相似文献
866.
867.
简述了计算全息光栅扫描器的特点和优点, 以及它有可能成为解决CO2 激光成像雷达的激光扫描这一关键技术的有效途径, 并给出当蚀刻深度为λ/4 = 2-65 μm 时, 传统的加工工艺受到的障碍及给出新的加工工艺和明显的实验效果。最后给出要想使计算全息光栅扫描器成为真正满足CO2激光成像雷达扫描技术的实用型光栅扫描器, 及其在理论和加工工艺上的发展趋势 相似文献
868.
869.
Kazumichi Matsumiya 《Optical Review》2006,13(1):39-45
An impression of a surface seen through holes is created when one fuses dichoptic pairs of discs with one member of each pair
black and the other white. This is referred to as the ‘sieve effect’. This stimulus contains no positional disparities. The
impression of depth in the sieve effect is most evident when the size, contrast, and rim thickness of rivalrous patterns are
such as to produce exclusive rivalry. I investigated how long it took for the sieve effect to recover from exclusive rivalry
suppression. The magnitude of perceived depth in the effect was measured after exclusive rivalry suppression of one half-image
of the sieve-effect stimulus. The results showed that the sieve effect takes approximately 630 ms to recover from exclusive
rivalry suppression, compared with 200 ms for disparity-based stereopsis. Considered together with the previous report [Matsumiya
and Howard: Invest. Ophthalmol. Visual Sci. 42 (2001) S403] that the sieve effect is positively correlated with the rate of exclusive rivalry, these findings suggest that
the effect and exclusive rivalry are processed in the identical channel. 相似文献
870.