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151.
Ozone (O3) generation in a dielectric barrier discharge (DBD) reactor driven by a pulsed power supply was investigated at atmospheric pressure and room temperature. An O3 generation efficiency model is established in which discharge power, O2 concentration, gas flow rate, and volume of the discharge space are included. Constants in the O3 generation efficiency model were obtained by fitting the model with experiment results. O3 concentration can be simply calculated from the energy density and initial O2 concentration. Comparison on O3 concentrations from calculation with references is given. 相似文献
152.
发动机是军舰上的重要部件之一,其稳定性对军舰的正常航行具有重要影响。以舰用发动机关键部件(主泵轴承)为具体研究对象,提出了基于功率谱包络能量和支持向量机相结合的故障诊断方法。首先获取了大量可表征舰用发动机主泵轴承健康状态的振动加速度信息,对其进行功率谱分析,获得其功率谱的包络能量;以获取的舰用发动机主泵轴承功率谱的包络能量构建特征向量,并设计基于SVM的舰用发动机主泵轴承故障诊断模型,对主泵轴承的故障进行诊断研究。研究结果表明,采用基于功率谱包络能量和SVM相结合的舰用发动机关键部件故障诊断方法,可以很好实现主泵轴承的故障诊断效能,为舰用发动机主泵轴承故障诊断的工程应用奠定了基础。 相似文献
153.
研究了绿色硫细菌中捕光天线复合物Fenna-Matthews-Olson的一个子单元和反应中心的能量传递.通过细菌叶绿素分子的能量和耦合强度,构建了包含反应中心的哈密顿量及约化模型.通过级联运动方程研究了不同分子间和反应中心的激子布居演化.计算了Fenna-Matthews-Olson及其约化模型的二维三阶光子回波谱,获得能量传榆过程中不同激子态间的相干性.结果表明在能量捕获过程中,Fenna-Matthews-Olson复合物存在冗余结构. 相似文献
154.
为延长稀有气体卤化物准分子激光器工作气体使用寿命,在原有供气设备基础上增加了工作气体实时补给技术.该技术采用FPGA控制系统将逐步提高放电电压、补充卤素气体和更换部分混合气体等操作有效组合起来.随着激光脉冲能量的下降,逐步提高放电电压;当放电电压达到最大值时,开始补充卤素气体,并恢复放电电压;当补充卤素气体效果不明显时,更换部分混合工作气体.将该技术应用于医用型ArF准分子激光器中进行实验研究,结果表明:在没有使用工作气体实时补给技术的情况下,激光器累计工作14.38 h后,输出单脉冲激光能量下降了17.2%;采用工作气体实时补给技术后,激光器输出能量下降速率明显降低,累计工作14.38 h,其单脉冲能量下降率能控制在3%范围内.因此,采用该技术可延长激光器工作气体的使用寿命、提高输出激光能量稳定性、减少停机次数并降低运行成本. 相似文献
155.
采用改进的坩埚下降法成功地生长了Tm/Yb共掺氟化钇锂单晶. 该单晶体具有每吸收一个蓝色光子并能发射出2个1000 nm近红外光子的下转换发光效应. 测定了样品的激发光谱、发射光谱和荧光衰减曲线. 在465 nm蓝光激发下观察到由Yb3+:2F5/2→2F7/2能级跃迁所致的960~1050 nm 波段的发射带,此发光带源于Tm3 对Yb3 离子的能量下转换过程. 应用Inokuti-Hirayama模型,研究了晶体的能量转换过程,结果表明Tm3 向Yb3 的能量传递是一个电偶极子相互作用机制过程. 当Tm3 与Yb3 离子的掺杂浓度为0.49mol%与5.99mol%时,单晶的量子剪裁效率达到最大值167.5%. 相似文献
156.
We investigate the energy structure of colloidal CdS nanocrystals by measuring the UV–vis absorption spectra. Nanocrystals were synthesized by sol–gel method in a gelatin matrix in the size range from 2.5 to 3.9 (±0.2) nm. In order to interpret the UV–vis absorption spectra we calculate the energy spectrum of electron quasi-stationary states using the model of open nanocrystal as well as the hole stationary spectrum in a two-band approach. It is shown that the main contribution to the absorption spectrum is made by interband transitions 1S3/2→1Se and 1P3/2→1Pe, and its shape is determined by the size distribution of nanoparticles. For this system the estimated values of the effective masses of the heavy hole and light hole are 1.44m0 and 0.28m0, respectively. 相似文献
157.
Hopkinson non-penetrating low-speed impact test was carried out on Kevlar flexible fabrics. The impact basin was formed by the clay on the back of the fabric, and the ultimate deformation of the fabric was recorded completely. The 3D shape of the clay impact basin was measured by fringe projection profilometry and converted into the impact basin volume. At the same time, the relationship between the indentation volume and the deformation energy of the clay was calibrated using the clay intrusion test. The clay impact basin volume is then converted into the residual energy of the flexible fabric subjected to the low-speed impact, and a new index of the impact basin volume is established to evaluate the energy absorption efficiency of fabric under the low-speed impact. Finally, combined with the deformation of single-layer fabric, the stress wave propagation in the impact deformation process of fabric is discussed, which is helpful to understand the impact energy absorption mechanism of flexible fabric. 相似文献
158.
Surface group-rich titanium carbide nanosheets (TCNSs) were successfully fabricated by simply etching Ti3AlC2 powders and used as dielectric fillers to promote the dielectric and energy storage performances of poly (vinylidene fluoride-hexafluoropropylene) (PVDF-HFP)-based composites. The PVDF-HFP/TCNS composites realize a high dielectric constant and low dielectric loss of 16.3 and 0.034 at 102 Hz, respectively. Importantly, a high energy storage density (Ue) of 0.367 J cm−3 at 900 kV cm−1 and a high energy storage efficiency (η ≥ 78.9%) at a TCNS content of only 0.5 wt% are obtained, which indicates that incorporating TCNS is an efficient route in enhancing Ue while maintaining a high level η of the PVDF-HFP-based composites. According to detailed characterization results, a mechanism related to the reduction of lamellar crystals in the PVDF-HFP matrix is suggested. The above mechanism restricts the movement of polymer chains near the filler-matrix interface and is proposed to be responsible for the outstanding dielectric and energy storage performances. Consequently, this work provides a simple and effective method for fabricating highly efficient energy storage nanocomposites. 相似文献
159.
Yingying Wang Zhuangdong Yuan Yunjie Guo Xuxiao Ma Zitong Meng Jingquan Sha Haifeng Zhang 《无机化学与普通化学杂志》2020,646(20):1696-1701
Two dinuclear LnIII-based clusters, namely [Dy2L2(NO3)2(DME)4] ( 1 ) and [Gd2L2(NO3)2(DME)4] ( 2 ) [H2L = (E)-2-((2-hydroxybenzylidene)amino)phenol] were obtained under hydrothermal condition. Two LnIII ions are bridged by two phenolic hydroxyl oxygen atoms, and the distances of them are 3.829 Å (Dy1–Dy1A) and 3.860 Å (Gd1–Gd1A). Two Dy1–O–Dy1A and Gd1–O–Gd1A angles are 109.4° and 109.8°, respectively. Magnetic studies reveal a weak antiferromagnetic interaction between Gd ions in complex 2 , and single-molecule magnet behavior for 1 with Ueff = 49.9 K and τ0 = 1.54 × 10–6 s. 相似文献
160.