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951.
952.
Y. Srivastava A. Widom E. Sassaroli 《Zeitschrift fur Physik C Particles and Fields》1995,66(4):601-605
Relativistic propagators, the natural tools in field theory to describe the space-time development of a quantum system, are used to study correlations and interferences present in the neutral kaon system due to time-reversal violations. The method allows for a general wave-packet treatment of the problem. While standard results are obtained for singleK decays, quite different results are derived for the interference phase in two kaon decays such as those at DAΦNE. 相似文献
953.
954.
Srubabati Goswami Raghavan Rangarajan K. Agashe A. Bandyopadhyay K. Bhattacharya B. Brahmachari C. Burgess E. J. Chun D. Choudhury P. K. Das A. Dighe R. Godbole S. Goswami N. Gupta M. Kaplinghat D. Indumathi J. Forshaw Y. Y. Keum B. Layek D. Majumdar N. Mahajan P. Mehta R. N. Mohapatra N. Mondai S. More Y. Nir S. Pakvasa M. K. Parida M. Ravikumar G. Rajasekaran P. Ramadevi R. Rangarajan S. D. Rindani D. P. Roy P. Roy N. Sahu A. Samanta Y. Shadmi A. M. Srivastava S. Uma Sankar R. Vaidya U. Yajnik 《Pramana》2004,63(6):1391-1405
This is the report of neutrino and astroparticle physics working group at WHEPP-8. We present the discussions carried out
during the workshop on selected topics in the above fields and also indicate progress made subsequently. The neutrino physics
subgroup studied the possibilities of constraining neutrino masses, mixing and CPT violation in lepton sector from future
experiments. Neutrino mass models in the context of Abelian horizontal symmetries, warped extra dimensions and in the presence
of triplet Higgs were studied. Effect of threshold corrections on radiative magnification of mixing angles was investigated.
The astroparticle physics subgroup focused on how various particle physics inputs affect the CMBR fluctuation spectrum, and
on brane cosmology. This report also contains an introduction on how to use the publicly available code CMBFAST to calculate
the CMBR fluctuations. 相似文献
955.
We show that cosmic strings moving through the plasma at the time of a first-order quark-hadron transition in the early universe
generate baryon inhomogeneities, which can survive till the nucleosynthesis epoch. We find out how these inhomogeneities actually
affect the calculated values of the light element abundances. Recently a wealth of observational data from various experiments
have helped to reduce the uncertainties in the values of these abundances. Using these we show that it is possible to derive
constraints in the presence of cosmic strings during the quark-hadron transition. 相似文献
956.
Shinoo SrivastavaSeema Srivastava Shyam SinghVishwambhar Dayal Gupta Vijai Prakash Gupta 《European Polymer Journal》2002,38(7):1423-1434
A study of the normal modes of vibration and their dispersion in polyurydilic acid (polyU) is reported using Wilson's GF Matrix method as modified by Higgs. This is done for the `bare' as well as for the helix `loaded' with uracil. Confusion that has prevailed regarding the assignments of the observed modes at 810 and 572 cm−1 is cleared and it is shown that the so called bare helix (polyU-U) has a different minimum energy state and hence spectrally different. Dispersion of the normal modes in the two helices shows marked differences which are characteristic of the extent of electrical/mechanical coupling along the chain and between the chain and the base. Values predicted for the heat capacity as a function of temperature for polyU is also reported. 相似文献
957.
D. Sinha S. Ghosh A. Srivastava V. G. Dedgaonkar K. K. Dwivedi 《Radiation measurements》1997,28(1-6):145-148
The effect of Gamma radiation in Polyallydiglycol carbonate (PADC) detectorrs has been studied in the dose range of 100–106 Gy. Some of the properties like bulk-etch rate, track-etch rate, activation energy for bulk and track-etching have been found out for different gamma doses from 60Co Source in PADC. The experimental results are presented and discussed. 相似文献
958.
Pande S. S. Borkar S. P. Prafulla S. Srivastava V. D. Behare A. Mukhopadhyay P. K. Ghodgaonkar M. D. Kataria S. K. 《Pramana》2004,63(2):459-463
Linear position sensitive detectors (PSDs) are widely used to configure neutron diffractometers and other instruments. Necessary
front-end electronics and a data acquisition system [1] is developed to cater to such instruments built around the Dhruva
research reactor in BARC. These include three diffractometers with multiple PSDs and four with single PSD. The front-end electronics
consists of high voltage units, preamplifiers [2],shaping amplifiers, ratio ADCs (RDC) [3]. The data acquisition system consists
of an interface card and software. Commercially available hardware like temperature controller or stepper motor controller
connected over GPIB or RS232 are also integrated in the data acquisition system. The data acquisition is automated so that
it can continue unattended for control parameter like temperature, thus enabling optimum utilization of available beam time.
The instrumentation is scalable and can be easily configured for various instrumental requirements. The front-end electronics
and the data acquisition system are described here. 相似文献
959.
An experimental study was undertaken to determine the effect of corrosive environments on the strength of adhesive joints
between pairs of glass-fiber-reinforced-plastic (GRP) plates and plates of GRP bonded to aluminum (Al). Two corrosive agents,
each in three concentrations, were used: sulphuric acid (30, 50 and 60 percent) and sodium chloride (15, 20 and 25 percent).
The results indicate a loss of strength with immersion time that levels off after a certain time. This loss of strength was
more severe for the sulphuric acid than for sodium chloride. Ultrasonic attenuation of the adhesive joints was also monitored
and it was found to increase with the immersion time, suggesting that the corrosion created inhomogenieties in the bond. The
loss of strength and the increase in ultrasonic attenuation were both greater for greater concentrations of each of the corrosive
agents. 相似文献
960.