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721.
Shukla Arpit Parmar Paritosh Kapoor Gitanjali Goswami Dweipayan Jha Chaitanya Kumar Patel Baldev Saraf Meenu 《Molecular diversity》2022,26(1):555-568
Molecular Diversity - Microbes possess a tremendous potential to interact with their surroundings and have continued to shape the future of all life forms existing on earth. Of all the groups of... 相似文献
722.
Amin Sk. Abdul Ghosh Kalyan Singh Samayaditya Qureshi Insaf Ahmed Jha Tarun Gayen Shovanlal 《Molecular diversity》2022,26(1):215-228
Molecular Diversity - Novel coronavirus disease 2019 (COVID-19) emerges as a serious threat to public health globally. The rapid spreading of COVID-19, caused by severe acute respiratory syndrome... 相似文献
723.
In this paper, we have explored and extended the use of frequency selective surface towards the terahertz regime of the electromagnetic spectrum where interesting applications such as imaging, sensing and communication exist. We have discussed a synthesis technique to design the single square loop frequency selective surface (SSLFSS) at 150 and 300 GHz which have found suitable application in the fast analysis and fabrication of the frequency selective surface. Moreover, the analytical results have been supported by the CST Microwave Studio and Ansoft HFSS commercial simulators. We have discussed the angular insensitivity of the SSLFSS at 150 GHz as well as 300 GHz. However, the specific problems arise at terahertz frequencies as compared to the radio and microwave frequencies are the ohmic losses. The proposed analysis has been extended from 100 GHz to 350 GHz to discuss the ohmic and dielectric losses. We have also discussed the other important issues which are very much significant in the terahertz regime of the spectrum such as skin depth and surface roughness. 相似文献
724.
A new four-step synthetic procedure has been developed to prepare 3,3-dimethyl-4-morpholino-3,4-dihydrocoumarins from substituted salicylaldehydes, morpholine, and isobutyraldehyde. It involves aminal formation, deamination, enamine formation, hetero-Diels–Alder reaction, hydrolysis, and oxidation. The aminal formation, subsequent one-pot domino deamination, enamine formation, and hetero-Diels–Alder reaction were achieved in microwave-assisted catalyst-free conditions. The following hydrolysis and oxidation steps, performed conventionally, gave quantitative yields. 相似文献
725.
S. Sugandhi V. M. Joshi S. K. Jha R. M. Tripathi 《Journal of Radioanalytical and Nuclear Chemistry》2014,302(3):1345-1348
The observed 137Cs content in bottom sediment and benthic species of Mumbai off coast varied between 2–370 \( {\text{Bq kg}}_{{ ( {\text{dry)}}}}^{ - 1} \) and <0.08–0.4 \( {\text{Bq kg}}_{{ ( {\text{wet)}}}}^{ - 1} \) respectively. The annual estimated ingestion dose to ‘general public’ due to consumption of benthic species is 0.02 µSv y?1, which is infinitesimally smaller, in comparison to average annual human exposure of 3.01 mSv and also to the internationally accepted public dose limit of 1,000 µSv y?1. 相似文献
726.
Nandini Vallavoju Dr. Sermadurai Selvakumar Dr. Steffen Jockusch Prof. Dr. Mukund P. Sibi Prof. Dr. Jayaraman Sivaguru 《Angewandte Chemie (International ed. in English)》2014,53(22):5604-5608
Can photocatalysis be performed without electron or energy transfer? To address this, organo‐photocatalysts that are based on atropisomeric thioureas and display lower excited‐state energies than the reactive substrates have been developed. These photocatalysts were found to be efficient in promoting the [2+2] photocycloaddition of 4‐alkenyl‐substituted coumarins, which led to the corresponding products with high enantioselectivity (77–96 % ee) at low catalyst loading (1–10 mol %). The photocatalytic cycle proceeds by energy sharing via the formation of both static and dynamic complexes (exciplex formation), which is aided by hydrogen bonding. 相似文献
727.
Gaoyuan Ma Dr. Jun Deng Prof. Dr. Mukund P. Sibi 《Angewandte Chemie (International ed. in English)》2014,53(44):11818-11821
Can organocatalysts that incorporate fluxional groups provide enhanced selectivity in asymmetric transformations? To address this issue, we have designed chiral 4‐dimethylaminopyridine (DMAP) catalysts with fluxional chirality. These catalysts were found to be efficient in promoting the acylative kinetic resolution of secondary alcohols and axially chiral biaryl compounds with selectivity factors of up to 37 and 51, respectively. 相似文献
728.
Dadi Niranjan Kumar Anik Roy Amarkant Jha Arvind Sambasivan Dr. G. Harikrishnan 《Chemphyschem》2014,15(18):4006-4010
The dimensionally restricted, diffusion‐driven volumetric change of almost flat nucleated surface nanobubbles hosted on dispersed nanoscale surfaces is proposed as the probable mechanism of heterogeneous bubble generation during polymer–nanoscale‐nucleant suspension foaming. By conducting numerical simulations, this hypothesis is used to predict the final bubble sizes upon polymeric foaming with nanoscale nucleants and to compare them with reported experimentally determined values. The volumetric change in the bubble hosted on the miniscule surface is envisaged to occur due to two parallel diffusion processes: 1) through the contact line of the bubble cap with the surface, and 2) through the curved gas–polymer interface. The foaming conditions determine the direction and molar rate of both these diffusions. The mechanism explains the relative nucleating efficiency of nanoscale surfaces experimentally observed during reactive and nonreactive polymeric foaming by predicting the growth or dissolution of the bubble. In the case of nonreactive thermoplastic foaming, the size of the bubbles released to the bulk from the nanoscale surface varies in a near linear fashion with respect to the size of the nucleants, limited to a maximum nucleant size. Beyond this maximum, the size of bubble generated is independent of the nucleant size. However, increase in the initial nanoscopic contact angle does not significantly affect the bubble size upon detachment from the surface. 相似文献
729.
Effect of gamma irradiation on X‐ray absorption and photoelectron spectroscopy of Nd‐doped phosphate glass
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V. N. Rai Parasmani Rajput S. N. Jha D. Bhattacharyya B. N. Raja Shekhar U. P. Deshpande T. Shripathi 《Journal of synchrotron radiation》2016,23(6):1424-1432
X‐ray absorption near‐edge structure (XANES) and X‐ray photoelectron spectroscopy (XPS) of Nd‐doped phosphate glasses have been studied before and after gamma irradiation. The intensity and the location of the white line peak of the L3‐edge XANES of Nd are found to be dependent on the ratio O/Nd in the glass matrix. Gamma irradiation changes the elemental concentration of atoms in the glass matrix, which affects the peak intensity of the white line due to changes in the covalence of the chemical bonds with Nd atoms in the glass (structural changes). Sharpening of the Nd 3d5/2 peak profile in XPS spectra indicates a deficiency of oxygen in the glasses after gamma irradiation, which is supported by energy‐dispersive X‐ray spectroscopy measurements. The ratio of non‐bridging oxygen to total oxygen in the glass after gamma radiation has been found to be correlated to the concentration of defects in the glass samples, which are responsible for its radiation resistance as well as for its coloration. 相似文献
730.
Jha PC Rinkevicius Z Agren H Seal P Chakrabarti S 《Physical chemistry chemical physics : PCCP》2008,10(19):2715-2721
The present work aims to establish the utility of dispersion-corrected density functional theory for potential energy curves of the benzene dimer, a problem that has received significant attention for a long time. The interaction energies of parallel-stacked, T-shaped and parallel-displaced benzene dimer configurations have been evaluated using both dispersion- and normal gradient-corrected Perdew-Burke-Ernzerhof functionals along with Dunning's augmented correlation-consistent polarized valence triple-zeta (aug-cc-pVTZ) basis functions and compared with explicit correlation methods. The potential energy curves for the parallel-stacked and parallel-displaced benzene dimers are in excellent agreement with highly accurate coupled cluster (CCSD(T)) results, while for the T-shaped benzene dimer the dispersion-corrected results show a distinct deviation, being closer in that case to the MP2 level of results. The overestimation of interaction energy in the T-shaped dimer may be attributed to the presence of a permanent dipole moment in this configuration and indicates a structural dependence of the dispersion-corrected density functional method. 相似文献