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191.
Stievater TH Li X Steel DG Gammon D Katzer DS Park D Piermarocchi C Sham LJ 《Physical review letters》2001,87(13):133603
Transient nonlinear optical spectroscopy, performed on excitons confined to single GaAs quantum dots, shows oscillations that are analogous to Rabi oscillations in two-level atomic systems. This demonstration corresponds to a one-qubit rotation in a single quantum dot which is important for proposals using quantum dot excitons for quantum computing. The dipole moment inferred from the data is consistent with that directly obtained from linear absorption studies. The measurement extends the artificial atom model of quantum dot excitonic transitions into the strong-field limit, and makes possible full coherent optical control of the quantum state of single excitons using optical pi pulses. 相似文献
192.
We present a theory to further a new perspective of proactive control of exciton dynamics in the quantum limit. Circularly polarized optical pulses in a semiconductor nanodot are used to control the dynamics of two interacting excitons of opposite polarizations. Shaping of femtosecond laser pulses keeps the quantum operation within the decoherence time. Computation of the fidelity of the operations and application to the complete solution of a minimal quantum computing algorithm demonstrate in theory the feasibility of quantum control. 相似文献
193.
Summary Piperidine reacts with the FeCI(o-H2NC6H4CO2)2 · H2O, (1) and FeCl(o-HOC6H4CO2)2 · H2O, (2), to give the piperidinido-N complexes, Fe(NC5H10)(o-H2NC6H4CO2)2 and Fe(NC5H10)(o-OC6H4CO2), respectively. n-Butylamine and pyridine, combine with (1) and (2) either by removal of water or by formation of simple addition compounds or chelate rings. The i.r. spectra, molar conductances, magnetic moments, molecular weights and thermal decompositions of some of these products have been studied. 相似文献
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196.
Ghulam Abbas Kandhro Tasneem Gul Kazi Sirajuddin Naveed Kazi Hassan Imran Afridi Muhammad Baial Arain Jameel Ahmed Baig Abdul Qadir Shah Sham Kumar Wadhwa Faheem Shah 《Russian Journal of Electrochemistry》2011,47(12):1355-1362
Iodine deficiency affects a substantial portion of the world’s population, provoking severe health problems as well as important
economic losses to the region in which this condition is found. In present study, evaluated the levels of urinary iodide (UI)
and thyroid hormone status in female hypothyroid patients (HPs) and control subjects of same age group 16–30 years. The UI
in HPs was measured by means of a Potentiometric method after microwave-assisted acid digestion, and compared the results
with those obtained by the Sandell-Kolthoff method. The validity and accuracy was checked by using certified reference materials.
The significantly lower concentration of iodide in the urine samples of the female goiter patients were observed as compared
to control/referents subjects (p < 0.001). Serum thyroid status thyroid stimulating hormone, free triiodothyronine and free thyroxin were significantly lower
in female patients as compared to control females (p < 0.003). The proposed method was relatively rapid, precise, accurate, efficient, as well as cost effective by using inexpensive
equipment. 相似文献
197.
F.C. Sham Y.H. Huang L. Liu Y.S. Chen Y.Y. Hung T.Y. Lo 《Infrared Physics & Technology》2010,53(1):1-9
Infrared thermography is a rapid, non-invasive and full-field technique for non-destructive testing and evaluation (NDT&E). With all the achievements on IR instrumentation and image processing techniques attained, it has been extended far beyond simple hot-spot detection and becomes one of the most promising NDT&E techniques in the last decades. It has achieved increasing acceptance in different sectors include medical imaging, manufacturing component fault detection and buildings diagnostic. However, one limitation of IR thermography is that the testing results are greatly affected by object surface emissivity. Surface with various emissivities may lead to difficult discrimination between area of defect and area with different emissivity. Therefore, many studies have been carried out on eliminating emissivity, for example, the time derivative approach, lock-in processing and differential contrast measurements. In these methods, sequence of themo-data/images are recorded and being processed in order to eliminate differences of emissivity. Another problem of IR thermography is that any obstruction may limit stimulations and imaging which leads to the observation of unclear defect image. To solve this problem, this paper proposes an algorithm based on the principle of computerized tomography which permits the reconstruction of unavailable/partially available temperature distribution of the affected area using the measured surrounding temperature field. In the process, a set of imaginary rays are projected from many different directions across the area. For each ray, integration of the temperature derivatives along the ray is equals to the temperature difference between the boundary points intercepted by the ray. Therefore, a set of linear equations can be established by considering the multiple rays. Each equation expresses the unknown temperature derivatives in the affected area in terms of the measured boundary temperature data. Solution of the set of simultaneous equations yields unknown thermal distribution in the area which needs to be reconstructed. Based on the proposed computerized tomography reconstruction (CTR) technique, deviated temperature data due to missing temperature data hidden by obstacle can be reconstructed. With further development, this technique may have the potential to be applied in the reconstruction of any smooth physical fields like phase information in optical techniques. 相似文献