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71.
72.
《Arabian Journal of Chemistry》2022,15(11):104302
Traditional Chinese medicine (TCM) is the key to unlock treasures of Chinese civilization. TCM and its compound play a beneficial role in medical activities to cure diseases, especially in major public health events such as novel coronavirus epidemics across the globe. The chemical composition in Chinese medicine formula is complex and diverse, but their effective substances resemble “mystery boxes”. Revealing their active ingredients and their mechanisms of action has become focal point and difficulty of research for herbalists. Although the existing research methods are numerous and constantly updated iteratively, there is remain a lack of prospective reviews. Hence, this paper provides a comprehensive account of existing new approaches and technologies based on previous studies with an in vitro to in vivo perspective. In addition, the bottlenecks of studies on Chinese medicine formula effective substances are also revealed. Especially, we look ahead to new perspectives, technologies and applications for its future development. This work reviews based on new perspectives to open horizons for the future research. Consequently, herbal compounding pharmaceutical substances study should carry on the essence of TCM while pursuing innovations in the field. 相似文献
73.
Joseph P. Sattler George J. Simonis 《International Journal of Infrared and Millimeter Waves》1984,5(4):465-473
We report the refractive indices and absorption coefficients for four beryllia (BeO) ceramic samples. These dielectric properties have been measured over the range from 4 to 18 cm–1 by use of a Michelson interferometer. The index n, follows the linear relationship n=0.6517 cm3/g×+0.7130 with density, , over the range 2.8<<3.0 g/cm3. 相似文献
74.
《Surface and interface analysis : SIA》2003,35(3):282-286
We have developed a high‐speed image processing CCD video camera for real‐time energy‐loss imaging using a conventional electron microscope with an energy‐loss imaging facility. As an initial demonstration of real‐time lock‐in energy‐loss imaging, a background‐subtracted energy‐loss image was observed by attaching the high‐speed image processing CCD video camera to an analytical electron microscope equipped with a floating‐type energy‐loss imaging analyser. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献
75.
Elena Khomko Leonid Mashlyakovskiy Claudio Tonelli 《Journal of polymer science. Part A, Polymer chemistry》2004,42(21):5354-5371
The effect of catalyst dibutyltin dilaurate (DBTDL) on the kinetics of urethane formation reactions of α,ω‐bis(hydroxy)‐terminated fluoropolyethers Fomblin® Z‐DOL TXs (FPEs) of various molecular weights and poly(oxyethylene) glycol PEG‐400 with isophorone diisocyanate (IPDI) in hexafluoroxylene (HFX) and tetrahydrofuran (THF) at 40 °C and NCO:OH = 2:1 have been studied in a broad range of catalyst (0.10–9.00) ×10?4 M and total reagents (10.0–60.1 wt %) concentrations. The rate of tin‐catalyzed second‐order reactions (with respect to diol and diisocyanate) was found to be proportional to the square root of catalyst concentration [DBTDL]0.5 both in low polar (HFX) and polar (THF) solvents. Effect of catalyst saturation was revealed for all the reaction systems at higher DBTDL concentrations as well as the appearance of the limiting catalyst concentrations Clim below which the rates of reaction were close to zero. Based on these findings new effective rate coefficients have been derived k = kcat/(C ? C) that are independent of the total reagent concentration in the range of 10.0–60.1 wt % ([OH] = 0.10–0.91 equiv/L). This new approach highlights that the rate of the tin‐catalyzed urethane formation reactions of α,ω‐bis(hydroxy)‐terminated fluoropolyethers Z‐DOL TXs with IPDI in HFX at 40 °C and NCO:OH = 2:1 increases significantly with increasing MW of FPE from 776 up to 3405. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 5354–5371, 2004 相似文献
76.
Ye Xu Dr. Huifeng Yao Lijiao Ma Ling Hong Jiayao Li Qing Liao Yunfei Zu Jingwen Wang Mengyuan Gao Prof. Long Ye Prof. Jianhui Hou 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(23):9089-9095
Decreasing the energy loss is one of the most feasible ways to improve the efficiencies of organic photovoltaic (OPV) cells. Recent studies have suggested that non-radiative energy loss ( ) is the dominant factor that hinders further improvements in state-of-the-art OPV cells. However, there is no rational molecular design strategy for OPV materials with suppressed . Herein, taking molecular surface electrostatic potential (ESP) as a quantitative parameter, we establish a general relationship between chemical structure and intermolecular interactions. The results reveal that increasing the ESP difference between donor and acceptor will enhance the intermolecular interaction. In the OPV cells, the enhanced intermolecular interaction will increase the charge-transfer (CT) state ratio in its hybridization with the local exciton state to facilitate charge generation, but simultaneously result in a larger . These results suggest that finely tuning the ESP of OPV materials is a feasible method to further improve the efficiencies of OPV cells. 相似文献
77.
Thermogravimetric analysis of hydroxyl terminated polybutadiene (HTPB) and its fractions of different molecular weights separated by preparative GPC shows two major stages of weight loss of different nature in a nitrogen atmosphere. The first stage is primarily depolymerisation, cyclisation and crosslinking of molecules and the second stage is mainly the decomposition of the residue from the first stage. The kinetic parameters, viz. activation energy E and pre-exponential factor A using four different non-isothermal integral equations show a systematic increase with increase in molecular weight for the first stage, whereas for the second stage, the effect of molecular weight on E and A values is not prominent. The increase in E and A values for the first stage is attributed to the formation of greater number of cyclised and crosslinked products from molecules of higher dimensions. Quantitative correlations between the kinetic constants and the molecular weight parameters were derived for the first stage as a quadratic curve following the equation: E or ln A = K1 − K2/M (where K1 and K2 are empirical constants whose values are different for the different molecular weight averages, viz. Mn, Mw and Mz and for the different equations). 相似文献
78.
苯乙烯-马来酸酐共聚物单分子膜的静、动态性质 总被引:3,自引:0,他引:3
对不同分子量的苯乙烯-马来酸酐共聚物(PSM)单分子膜的π-A等温线、微 分曲线进行了研究,讨论了PSM单分子膜成膜过程及分子量对膜相变的影响,并用 动态膜障振动法测定了PSM单分子膜的动态弹性,结果表明,分子链的相互作用( 如卷曲和缠结)在膜的形成中起着重要的作用,并影响膜的静、动态性质,单分子 膜的动态弹性曲线有双峰,且前者比后者小,随分子量增大,膜的凝聚性、刚性和 稳定性都增强,动态弹性都增大;且分子链的相互作用对PSM单分子性质影响增大 ,压缩过程中单分子膜的相变更明显。 相似文献
79.
80.
《Surface and interface analysis : SIA》2003,35(2):174-178
Effective energy‐loss functions for Al, Cu, Ag and Au were derived from the reflection electron energy‐loss spectroscopy (REELS) spectra for 1 keV electrons using extended Landau theory. Features of the obtained effective energy‐loss functions are close to those of optical surface energy‐loss functions, revealing the significant contribution of the low energy loss below a few tens of electron‐volts in the REELS spectrum for Cu, Ag and Au. The REELS spectra were reproduced using the newly derived effective energy‐loss functions, leading to the confirmation that this type of database of the effective energy‐loss function is very useful not only for more comprehensive understanding of the measured spectrum of surface electron spectroscopies but also for practical background subtraction in surface electron spectroscopy. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献