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241.
Nair V Vellalath S Poonoth M Suresh E 《Journal of the American Chemical Society》2006,128(27):8736-8737
Nucleophilic heterocyclic carbene-catalyzed cyclopentannulation of enals and chalcones via homoenolate has been observed for the first time. Serendipitously, the reaction lead to a very efficient synthesis of 3,4-trans-disubstituted-1-aryl cyclopentenes instead of the expected cyclopentanones. The strategy works well with thienylidene tetralone also, leading to the tricyclic cyclopentene derivative. 相似文献
242.
Amplitude and phase analysis in digital dynamic holography 总被引:1,自引:0,他引:1
Lensless in-line digital holographic interferometry has the potential for vibration analysis of objects smaller than 5 mm in diameter. This is particularly useful for dynamic characterization of microelectromechanical systems devices. To achieve this, there is a need to magnify the object wave, which is done using a diverging beam. It is observed that an increase in the object-to-CCD distance increases the sensitivity of the amplitude-modulated time-average fringes. At the same time the effect on phase information that represents the mean static deformation of a vibrating object is studied. It is also observed that a reduction in the object-to-CCD distance increases the phase sensitivity as evidenced by the double-exposure time-average fringes. The experimental observation and a theoretical explanation for this contradictory phenomenon are presented. 相似文献
243.
244.
Response of thermal source in a transversely isotropic thermoelastic half-space with mass diffusion by finite element method 下载免费PDF全文
The two-dimensional problem of generalized thermoelastic diffusion material with thermal and diffusion relaxation times is investigated in the context of Lord-Shulman theory. As an application of the problem, a particular type of thermal source is considered and the problem is solved numerically by using a finite element method. The components of displacement, stress, temperature distribution, chemical potential, and mass concentration are obtained. The resulting quantities are depicted graphically for a special model. Appreciable effect of relaxation times is observed on various resulting quantities. 相似文献
245.
Savitha Thayumanasundaram Vijay Shankar Rangasamy Jin Won Seo Jean-Pierre Locquet 《Ionics》2018,24(5):1339-1347
We report the synthesis of Li2CoSiO4 by the sol-gel method and the preparation of a composite electrode by incorporating functionalized multi-walled carbon nanotubes (fn. MWCNTs) as conductive additive. XRD pattern of the composite confirms the structural stability of Li2CoSiO4 even after the addition of fn. MWCNTs. SEM images of the composite reveal the presence of conductive bridges formed by MWCNTs between the submicron-sized particles of Li2CoSiO4. The cyclic voltammograms of the composite cathode show redox peaks with higher current density than pure Li2CoSiO4 and the current density increases with increase in sweep rate. The diffusion coefficient of lithium has been improved by the addition of fn. MWCNTs from 1 × 10?14 to 8 × 10?14 cm2/s as calculated using Randles-Sevcik equation. The charge-discharge cycling performance of both pure Li2CoSiO4 and composite cathode has been discussed. 相似文献
246.
Vijay Singh Jun-Jie Zhu Manoj Tiwari Manish Soni Mahendra Aynayas Seok-Hee Hyun R. Narayanan Manoj Mohapatra V. Natarajan 《Journal of Non》2009,355(50-51):2491-2495
Strong blue-green light emitting Eu doped SrAl2O4 phosphor was synthesized by a low-temperature initiated, self-propagating and gas producing combustion process in a very short time (<5 min). The prepared powder was characterized by X-ray diffraction, Fourier-transform infrared spectrometry and scanning electron microscopy. The excitation spectrum shows a peak at 397 nm. Upon excitation at 397 nm, the emission spectrum exhibits a well defined broad band with maximum at 493 nm corresponding to 4f65d → 4f7 transition. Electron paramagnetic resonance (EPR) measurements at X-band showed low field signals due to Eu2+ ions in SrAl2O4:Eu. 相似文献
247.
Mihai Cosmin Corobea Oana Muhulet Florin Miculescu Iulian Vaile Antoniac Zina Vuluga Dorel Florea Dumitru Mircea Vuluga Maria Butnaru Daniela Ivanov Stefan Ioan Voicu Vijay Kumar Thakur 《先进技术聚合物》2016,27(12):1586-1595
In this study, a new class of heterogeneous membranes based on cellulose acetate (CA) polymer and a complex filler clay‐silica nanowires (SiO2NWs) was investigated for potential biomedical applications. SiO2NWs were synthesized using natural clay through a facile sol–gel method and were dispersed in the polymer solution by sonication in the 1.25, 2.5, and 5% weight ratio to the CA acetate polymer. Membranes were subsequently prepared via phase inversion by precipitation of the CA polymer in water. The pristine CA membrane and SiO2NWs based nanocomposites membranes were characterized using different characterization techniques. The presence of the SiO2NWs in the CA membrane was found to significantly enhance the protein retention, water wettability and thermal as well as mechanical properties in comparison to the pristine CA membrane. Water flows studies at different temperatures and the retention of bovine serum albumin have been studied and the nanocomposite membranes were found to exhibit superior performances compared with the pristine CA membranes. SiO2NWs‐CA membranes showed a much higher stability to the water temperature change during separation than CA membranes. Morphological changes clearly revealed that the composite membrane were much more compact than the pristine CA membranes. The rabbit dermal fibroblasts cell viability in cultures after 72 hr of incubation was found to be greater than 80%. These newly synthesized composite membranes exhibit a high potential to be used for various medical applications because of their non‐cytotoxic characteristics. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
248.
Recent hardware and software advances have enabled simulation studies of protein systems on biophysically-relevant timescales, often revealing the need for improved force fields. Although early force field development was limited by the lack of direct comparisons between simulation and experiment, recent work from several labs has demonstrated direct calculation of NMR observables from protein simulations. Here we quantitatively evaluate recent molecular dynamics force fields against a suite of 524 chemical shift and J coupling ((3)JH(N)H(α), (3)JH(N)C(β), (3)JH(α)C', (3)JH(N)C', and (3)JH(α)N) measurements on dipeptides, tripeptides, tetra-alanine, and ubiquitin. Of the force fields examined (ff96, ff99, ff03, ff03*, ff03w, ff99sb*, ff99sb-ildn, ff99sb-ildn-phi, ff99sb-ildn-nmr, CHARMM27, OPLS-AA), two force fields (ff99sb-ildn-phi, ff99sb-ildn-nmr) combining recent side chain and backbone torsion modifications achieve high accuracy in our benchmark. For the two optimal force fields, the calculation error is comparable to the uncertainty in the experimental comparison. This observation suggests that extracting additional force field improvements from NMR data may require increased accuracy in J coupling and chemical shift prediction. To further investigate the limitations of current force fields, we also consider conformational populations of dipeptides, which were recently estimated using vibrational spectroscopy. 相似文献
249.
Ionic liquid catalyzed synthesis of 7-phenyl-1,4,6,7-tetrahydro-thiazolo[5,4-d]pyrimidine-2,5-diones
Prashant Singh Kamlesh Kumari Monica Dubey Vijay K. Vishvakarma Gopal K. Mehrotra Narender D. Pandey Ramesh Chandra 《Comptes Rendus Chimie》2012,15(6):504-510
A simple, green and catalyst free one pot synthesis of 7-phenyl-1,4,6,7-tetrahydro-thiazolo[5,4-d]pyrimidine-2,5-diones via a multicomponent reaction between thiazolidine-2, 4-dione (TZD), aromatic aldehyde and urea analogues is described. The ionic liquid has been used as a solvent as well as catalyst for this reaction. This reaction proceeded smoothly in good to excellent yields and offered several other advantages including short reaction time, simple experimental workup procedure and no by-products. 相似文献
250.
This paper presents anthraquinone and benzimidazole based hybrid molecular architect as the state of the art for multifunctional molecular logic circuits. The moleculator exhibits differential output behavior towards F(-), Zn(2+) and Cu(2+) ions to provide opportunities for elaboration of XOR, INHIBIT, XNOR, AND, OR, NOR, logic functions and their integrated logic functions half-adder, half-subtractor and comparator within a single molecule. These integral logic functions can be reprogrammed by self-annihilation or by another additional input in the same cell. This single molecule behaves uniquely where different logic functions can be operated and reset by using different inputs and outputs. 相似文献