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161.
Toward multiple maximum power point estimation of photovoltaic systems based on semiconductor theory
Jen‐Cheng Wang Yu‐Li Su Kun‐Chang Kuo Jyh‐Cherng Shieh Joe‐Air Jiang 《Progress in Photovoltaics: Research and Applications》2015,23(7):847-861
Environmental conditions, such as temperature, non‐uniform irradiation, and solar shading, deeply affect the characteristics of photovoltaic (PV) modules in PV‐assisted generation systems. Several local maximum power points (MPPs) are found in the power–voltage curve of PV systems constructed by series/parallel‐connected PV modules under partially shaded conditions. The characteristics of PV systems change unpredictably when multiple MPPs occur, so the actual MPP tracking (MPPT) becomes a difficult task. Conventional MPPT methods for the PV systems under partially shaded conditions cannot quickly find the actual MPP such that the optimal utilization of PV systems cannot be achieved. Based on the p–n junction semiconductor theory, we develop a multipoint direct‐estimation (MPDE) method to directly estimate the multiple MPPs of the PV systems under partially shaded conditions and to cope with the mentioned difficulties. Using the proposed MPDE method, the multiple MPPs of the PV systems under partially shaded conditions can be directly determined from their irradiated current–voltage and power–voltage characteristic curves. The performances of the proposed MPDE method are evaluated by examining the characteristics of multiple MPPs of PV systems with respect to different shading strengths and numbers of the shaded PV modules and also tested using the field data. The experimental results demonstrate that the proposed MPDE method can simply and accurately estimate the multiple MPPs of the PV systems under partially shaded conditions. The optimization of MPP control models and the MPPT for PV systems could be achieved promisingly by applying the proposed method. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
162.
Hongfei Cheng Kuo Li Qinfu Liu Shuai Zhang Xiaoguang Li Ray L. Frost 《Journal of Thermal Analysis and Calorimetry》2014,117(3):1231-1239
The thermal decomposition process of kaolinite–potassium acetate intercalation complex has been studied using simultaneous thermogravimetry coupled with Fourier-transform infrared spectroscopy and mass spectrometry (TG-FTIR-MS). The results showed that the thermal decomposition of the complex took place in four temperature ranges, namely 50–100, 260–320, 320–550, and 650–780 °C. The maximal mass losses rate for the thermal decomposition of the kaolinite–potassium acetate intercalation complex was observed at 81, 296, 378, 411, 486, and 733 °C, which was attributed to (a) loss of the adsorbed water, (b) thermal decomposition of surface-adsorbed potassium acetate (KAc), (c) the loss of the water coordinated to potassium acetate in the intercalated kaolinite, (d) the thermal decomposition of intercalated KAc in the interlayer of kaolinite and the removal of inner surface hydroxyls, (e) the loss of the inner hydroxyls, and (f) the thermal decomposition of carbonate derived from the decomposition of KAc. The thermal decomposition of intercalated potassium acetate started in the range 320–550 °C accompanied by the release of water, acetone, carbon dioxide, and acetic acid. The identification of pyrolysis fragment ions provided insight into the thermal decomposition mechanism. The results showed that the main decomposition fragment ions of the kaolinite–KAc intercalation complex were water, acetone, carbon dioxide, and acetic acid. TG-FTIR-MS was demonstrated to be a powerful tool for the investigation of kaolinite intercalation complexes. It delivers a detailed insight into the thermal decomposition processes of the kaolinite intercalation complexes characterized by mass loss and the evolved gases. 相似文献
163.
Jun-Wei Chen Yu-Yi Kuo Kuan-Ting Chen Chao-Ran Wang Chih-Yu Chao 《Molecular Crystals and Liquid Crystals》2015,611(1):139-145
We demonstrate that the supramolecular structure can be formed through the fibrous self-assembly of the polyfluorene-based polymer F8BT in liquid crystal (LC) 5CB. With the utility of alignment layer, the F8BT molecules can be aligned and formed oriented polymer network. We found that the presence of oriented polymer network makes twisted nematic LC exhibit excellent electro-optical properties (EO) of driving voltage reduction and EO bump peak elimination. The polyfluorene-based supramolecular structure provides the function of stabilizing LC molecules. We consider this functional self-assembled network has potential to apply in various devices for the ability of improving performance in operating property. 相似文献
164.
meso‐Ester and Carboxylic Acid Substituted BODIPYs with Far‐Red and Near‐Infrared Emission for Bioimaging Applications 下载免费PDF全文
Yong Ni Prof. Lintao Zeng Dr. Nam‐Young Kang Prof. Kuo‐Wei Huang Prof. Liang Wang Zebing Zeng Prof. Young‐Tae Chang Prof. Jishan Wu 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(8):2301-2310
A series of meso‐ester‐substituted BODIPY derivatives 1–6 are synthesized and characterized. In particular, dyes functionalized with oligo(ethylene glycol) ether styryl or naphthalene vinylene groups at the α positions of the BODIPY core ( 3 – 6 ) become partially soluble in water, and their absorptions and emissions are located in the far‐red or near‐infrared region. Three synthetic approaches are attempted to access the meso‐carboxylic acid (COOH)‐substituted BODIPYs 7 and 8 from the meso‐ester‐substituted BODIPYs. Two feasible synthetic routes are developed successfully, including one short route with only three steps. The meso‐COOH‐substituted BODIPY 7 is completely soluble in pure water, and its fluorescence maximum reaches around 650 nm with a fluorescence quantum yield of up to 15 %. Time‐dependent density functional theory calculations are conducted to understand the structure–optical properties relationship, and it is revealed that the Stokes shift is dependent mainly on the geometric change from the ground state to the first excited singlet state. Furthermore, cell staining tests demonstrate that the meso‐ester‐substituted BODIPYs ( 1 and 3 – 6 ) and one of the meso‐COOH‐substituted BODIPYs ( 8 ) are very membrane‐permeable. These features make these meso‐ester‐ and meso‐COOH‐substituted BODIPY dyes attractive for bioimaging and biolabeling applications in living cells. 相似文献
165.
María José Heras‐Ojea Daniel Reta Mañeru Lidia Rosado Dr. Juan Rubio Zuazo Dr. German R. Castro Subrata Tewary Dr. Gopalan Rajaraman Dr. Guillem Aromí Dr. Erika Jiménez Dr. E. Carolina Sañudo 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(33):10439-10445
The new diimine fluorescent ligand ACRI‐1 based on a central acridine yellow core is reported along with its coordination complex [Co2( ACRI‐1 )2] ( 1 ), a fluorescent weak ferromagnet. Due to the strong fluorescence of the acridine yellow fluorophore, it is not completely quenched when the ligand is coordinated to CoII. The magnetic properties of bulk complex 1 and its stability in solution have been studied. Complex 1 has been deposited on highly ordered pyrolitic graphite (HOGP) from solution. The thin films prepared have been characterized by AFM, time‐of‐flight secondary ion mass spectrometry (TOF‐SIMS), grazing incidence X‐ray diffraction (GIXRD), X‐ray absorption spectroscopy (XAS), X‐ray magnetic circular dichroism (XMCD) and theoretical calculations. The data show that the complex is robust and remains intact on the surface of graphite. 相似文献
166.
Highly Curved Bowl‐Shaped Fragments of Fullerenes: Synthesis,Structural Analysis,and Physical Properties 下载免费PDF全文
Min‐Kuan Chen Hsin‐Ju Hsin Dr. Tsun‐Cheng Wu Bo‐Yan Kang Yen‐Wei Lee Prof. Ming‐Yu Kuo Prof. Yao‐Ting Wu 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(2):598-608
Highly curved buckybowls 3 , 4 , and 5 were synthesized from planar precursors, fluoranthenes 8 , benzo[k]fluoranthenes 10 and naphtho[1,2‐k]‐cyclopenta[cd]fluoranthenes 12 , respectively, using straightforward palladium‐catalyzed cyclization reactions. These fluoranthene‐based starting materials were easily prepared from 1,8‐bis(arylethynyl)naphthalenes 6 . Both buckybowls 3 and 4 are fragments of C60, whereas 5 is a unique subunit of C70. The curved structures were identified by X‐ray crystallography, and they are deep bowls. The maximum π‐orbital axis vector (POAV) pyramidalization angle in both 3 and 4 is 12.8°. Such a high curvature is very rarely obtained. Buckybowls 5 are less curved than the others because they have a lower density of five‐membered rings, analogous to the tube portion of C70. Cyclopentaannulation increases the bowl depths of 3 and 4 , but not the maximum POAV pyramidalization angle. Among the eight buckybowls studied herein, five form polar crystals. The bowl‐to‐bowl inversion dynamics of these buckybowls can be classified into two types; one has a planar transition structure, whereas the other has an S‐shaped transition structure. A larger longitudinal length of these buckybowls corresponds to a stronger preference for the latter. The photophysical properties of these buckybowls were examined and compared with those of C60 and C70. Buckybowls 5 have absorption bands at wavelengths greater than 450 nm, which are similar to those of C70. The chiral resolution of the mono‐substituted buckybowl 4 ac was also studied by using HPLC with a chiral column. 相似文献
167.
Marcel Scheepstra Dr. Lidia Nieto Dr. Anna K. H. Hirsch Dr. Sascha Fuchs Dr. Seppe Leysen Chan Vinh Lam Leslie in het Panhuis Prof. Dr. Constant A. A. van Boeckel Dr. Hans Wienk Prof. Dr. Rolf Boelens Dr. Christian Ottmann Dr. Lech‐Gustav Milroy Prof. Dr. Luc Brunsveld 《Angewandte Chemie (International ed. in English)》2014,53(25):6443-6448
168.
Zhibo Liu Maral Pourghiasian Mark Alex Radtke Joseph Lau Dr. Jinhe Pan Gemma M. Dias Dr. Donald Yapp Dr. Kuo‐Shyan Lin Prof. Dr. Francois Bénard Prof. Dr. David M. Perrin 《Angewandte Chemie (International ed. in English)》2014,53(44):11876-11880
A new zwitterionic organotrifluoroborate is appended to three radiosynthons that afford undergo facile bioconjugation to several clinically relevant peptides and one enzyme inhibitor. Molecularly complex bioconjugates are 18F‐labeled in a single aqueous step in rapid time (<15 min) without HPLC purification to afford tracers in good yields (>200 mCi, 20–40 %) at high specific activity (≥3 Ci/μmol) and at >98 % purity. PET imaging shows in vivo stability and tumor uptake. 相似文献
169.
Gwo-Geng Lin Dar-Jong Lin Li-Jung Wang Ting-Wei Kuo 《Research on Chemical Intermediates》2014,40(6):2259-2268
In this study, carbon dioxide was used as a foaming agent for common plastics, such as acrylonitrile–butadiene–styrene (ABS) polymer, polystyrene (PS), polypropylene (PP), high-density polyethylene (HDPE), and high impact polystyrene (HIPS). Carbon dioxide was first absorbed by the sample plastics placed within a pressure vessel at various pressure levels and absorption time intervals. The Henry’s constant of the absorbed carbon dioxide in the plastics was determined. The diffusion coefficient of carbon dioxide in polymer was also identified by curve-fitting with the relationship between the absorbed amount and time. The results showed that ABS, PS, and HIPS absorbed more gas than did PP and HDPE, because PP and HDPE exhibit higher crystallinity. Generally, a polymer can take up saturation absorption of gas under higher pressure. After absorption, the foaming process occurred at various temperatures and time intervals. The cell structure, density, and size of the plastic foams were then investigated using scanning electron microscopy. A longer foaming period and higher temperature increase the size of the cell and decrease the cell density (the number of bubbles per unit volume). A dense skin layer without bubbles appeared directly adjacent to the surface of the foamed plastics. Its thickness decreased if the foaming process took place at higher temperatures. 相似文献
170.
We have performed Photoreflectance (PR), Raman Scattering (RS), and Photoluminescence (PL) experiments to characterize the In0.52Al0.48As surface exposed to plasma by a gas mixture of CH4/H2/Ar, PR spectra indicate that RIE (plasma) causes defects such as nonradiative recombination centers, scattering centers, and defects leading to the decrease of signal intensity, broaden line width and red shift of the transitions by increasing the rf power. In the Raman scattering study, RIE causes defects against InAs-like and AlAs-like LO modes vibration. As the rf power increased, the maximum of two LO modes shifts towards lower frequency and the line shape becomes increasingly asymmetric. Also, the intensity degrades gradually by disorder and point defects with increasing rf power. The PL transition energies show a red-shift with increasing the rf power. In addition, the spectral feature broadens, and the intensity decreases with rf power higher than 200 w. The consistence of the PL, PR, and RS results indicate that these three methods can be used as sensitive probes to evaluate the near surface damage of the epilayer. 相似文献