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961.
M. Beck U. Vogt I. Will A. Liero H. Stiel W. Sandner T. Wilhein 《Optics Communications》2001,190(1-6):317-326
We describe the development of a table top soft X-ray source based on a laser produced plasma. The plasma is produced by a Nd:YLF pulse-train laser which delivers pulse trains of up to 400 pulses each of about 25 ps duration. Number and energy of the micropulses are fully computer controlled adjustable for an optimum interaction with a rotating solid target. Spectral, spatial and temporal characteristics of the X-ray emission from Mylar and copper targets have been studied. A calibrated back-illuminated CCD camera together with a slit grating spectrograph were utilized for the measurement of the absolute soft X-ray photon fluxes. The temporal measurements were performed using a streak camera while the plasma size was measured with a zone plate. An application of the system in a X-ray absorption experiment is shown. The advantages of the system in view of possible optical pump and soft X-ray probe experiments will be discussed. 相似文献
962.
An optical frequency comb generator (OFCG) at 1064 nm with a modulation frequency of 2 GHz is developed for an accurate optical frequency link between iodine absorption lines near 532 nm. With the OFCG, we have measured frequency differences between seventeen 127I2 transitions with a measurement uncertainty of about 240 Hz (relatively 4.3×10−13), which is mainly contributed from the frequency repeatability of iodine-stabilized Nd:YAG lasers. The measured transitions provide an attractive frequency reference network and are excellent candidates for the practical realization of the meter. 相似文献
963.
用相对论多组态 (HXR)方法 ,详细计算了类Ne氪离子 4d 2 p类Na 3l4l′双电子伴线波长和强度因子 ,并模拟了实验光谱 ,解释了最新利用激光气体靶产生的 0 .5 2 5~ 0 .5 5 5nm范围的氪X Ray光谱 ,计算结果与实验符合得相当好。此外 ,还讨论了组态相互作用对双电子伴线结构的影响。 相似文献
964.
Abstract. Shock tubes often experience temperature and pressure nonuniformities behind the reflected shock wave that cannot be neglected
in chemical kinetics experiments. Because of increased viscous effects, smaller tube diameters, and nonideal shock formation,
the reflected-shock nonidealities tend to be greater in higher-pressure shock tubes. Since the increase in test temperature
() is the most significant parameter for chemical kinetics, experiments were performed to characterize in the Stanford High Pressure Shock Tube using infrared emission from a known amount of CO in argon. From the measured change
in vibrationally equilibrated CO emission with time, the corresponding ddt (or for a known time interval) of the mixture was inferred assuming an isentropic relationship between post-shock temperature
and pressure changes. For a range of representative conditions in argon (24–530 atm, 1275–1900 K), the test temperature 2
cm from the endwall increased 3–8 K after 100 s and 15–40 K after 500 s, depending on the initial conditions. Separate pressure measurements using a shielded piezoelectric transducer confirmed
the isentropic assumption. An analytical model of the reflected-shock gas dynamics was also developed, and the calculated
's agree well with those obtained from experiment. The analytical model was used to estimate the effects of temperature and
pressure nonuniformities on typical chemical kinetics measurements. When the kinetics are fast (s), the temperature increase is typically negligible, although some correction is suggested for kinetics experiments lasting
longer than 500 s. The temperature increase, however, has a negligible impact on the measured laser absorption profiles of OH (306 nm) and
CH (216 nm), validating the use of a constant absorption coefficient. Infrared emission experiments are more sensitive to temperature
and density changes, so nonuniformities should be taken into account when interpreting ir-emission data.
Received 25 April 2000 / Accepted 8 September 2000 相似文献
965.
应用几何光学近似理论模型计算了激光相位多普勒系统中微粒的光散射特性,得到了散射光强与粒径关系、检测器表现的散射光强分布、相位差与粒径特性中的非线性跃变以及检测器形状对特性的影响。 相似文献
966.
967.
激光对分子振动态的控制与量子Fredkin逻辑门 总被引:1,自引:1,他引:0
基于激光相干合成分子的局域模振动态,提出利用激光对分子振动态的控制实现量子Fredkin逻辑门的功能,并对方案的特点及可行性进行分析. 相似文献
968.
Zhang Xiaofang Wang Baoguang Jiang Chengzhi He Shunzhong Chen Lincai Zhang Xiaoyuan 《Chinese Journal of Lasers》2001,10(2):97-101
1 Foreword DopplerfrequencyshiftandinterferencefrequencymixingmustbeproducedintheopticalsystemofalongitudinaldisplacementmeasurementsystembasedonlaserDopplereffect.Inatypicaldifferentialopticalsystem ,theobjectmustbelocatedinthefocalplaneoflenstoensur… 相似文献
969.
利用激光溅射法直接产生了锰/磷、钛/磷二元团簇正、负离子MxPy^±(M=Mn、Ti) ,并用串级飞行时间质谱仪研究了团簇离子的组成与激光光解规律。实验表明钛与磷间成簇的能力强于锰与磷间成簇的能力,且MPy^+(M=Ti、Mn)团簇离子系列表现出峰强度了胡所含磷原子数目的奇偶性变化,这可能与P4结构的特殊稳定性有关。激光光解实验表明,失去中性P2、P4的通道为主要光解通道。随着团簇离子的生长,锰/磷团簇正离子逐渐由富磷簇向富金属簇过渡,钛/磷则趋向于形成钛原子数目与磷原子数目接近相等的团簇正离子,而二者与磷形成的团簇负离子MxPy^-(M=Mn、Ti) 逐渐趋向于x ≈ y,随样品中磷含量增加,锰/磷易形成富磷簇,钛/磷的组成趋向不改变。 相似文献
970.
激光促进甲醇在杂多化合物上的表面反应 总被引:1,自引:0,他引:1
利用红外光谱 (IR)、程序升温脱附 (TPD)和激光促进表面反应 (L SSR)技术 ,研究了甲醇吸附于杂多化合物 H3PMo1 2 O40 · x H2 O、H3PW1 2 O40 · x H2 O、H6 PMo6 W6 O40 · x H2 O表面上所形成体系的振动结构、化学吸附形态和光促表面反应规律 .实验结果表明 ,在各固体材料表面上甲醇同时发生分子吸附和解离吸附 ,且在室温条件下体系即发生显著的光促表面反应 ;与甲醇吸附强度和吸附量相比 ,反应体系的振动结构对 L SSR效率起着更重要的作用 .根据表征和反应结果 ,分析了体系中活性物种的产生途径 ,并给出了反应机理的模型 相似文献