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971.
Saposhnikovia divaricata is a commonly used traditional Chinese medicine in treating various diseases such as pyrexia, rheumatism and headache. So far, there have been few reports on the metabolism of orally administered Saposhnikovia divaricate decoction (SDD), hindering further study on its bioactive components and their pharmacological characteristics. In the present study, ultra-performance liquid chromatography–quadrupole time-of-flight mass spectrometry (UHPLC–Q-TOFMS) was used coupled with principal component analysis (PCA) and partial least squared discriminant analysis (PLS-DA) to rapidly discover and identify the metabolites of SDD. According to the result of PLS-DA, a total of 139 ions of interest including 87 positive ions and 52 negative ions were extracted as SDD-related xenobiotics in urine. Finally, 12 and 65 compounds were identified as absorbed parent components and metabolites of SDD, respectively. Among them, 40 new metabolites were reported for the first time. Our results suggested that hydrolysis, hydroxylation, glucuronidation and sulfation are the major metabolic pathways of chromones, while hydroxylation, hydrogenation and sulfation are the main metabolic pathways of coumarins. This study is the first to explore the absorption and metabolism of SDD using UHPLC–Q-TOFMS, with results providing a basis for further study of its pharmacokinetics and discovery of its bioactive components.  相似文献   
972.
    
Circulating tumor DNA(ctDNA),carrying tumor-specific sequence mutations,is a promising biomarker for classification,diagnosis and prognosis of cancers.However,there is still a great challenge in discriminating single-base difference between ctDNA and its coexisting analogue(normal circulating DNA,ncDNA)at a serum sample.A locked nucleic acid(LNA)probe combined with a-HL nanopore sensor was designed,which achieved a high signal-to-background ratio(SBR)of^8.34 × 10^3,as well as a significant discrimination capability(~12.3 times)of single-base diffe rence.The accurate discrimination strategy is label-free,convenient,selective and sensitive,which has great potential in the early diagnosis of diseases and biomedical research fields.  相似文献   
973.
    
A metamaterial absorber is proposed that functions in the medium- (3–5 µm) and long-wavelength (8–12 µm) infrared (medium-wavelength infrared, MWIR, and long-wavelength infrared, LWIR, respectively) regions. The proposed design, which consists of periodic cells, can be tuned to achieve single-band or dual-band light absorption by changing the periodicity of the structure. Each cell forming the metamaterial absorber consists of a bottom metal plate (Al), a top metal disk (Ti), and an intermediate dielectric medium (Si or ZnS) in which a metal disk (Ti) is embedded. For a period of 0.85 µm, the absorber achieves broadband absorption in the LWIR region, with an average absorption of 92.1%. Further, the absorber shows acceptable tolerance to irradiation at oblique incidence. For a period of 2 µm, a peak absorption of 99.05% is achieved in the MWIR region, thereby providing dual-band absorption. Tuning the periodicity of the structure enhances the localized surface plasmon resonance, with the absorption mechanism explained by establishing an equivalent parallel LC circuit. The absorption properties demonstrated by the proposed metamaterial absorber are promising for thermal imaging and infrared spectroscopy.  相似文献   
974.
    
Now, there have been many different methods to calculate one-loop amplitudes. Two of them are the unitarity cut method and the generalized unitarity cut method. In this short paper, we present an explicit connection between these two methods, especially how the extractions of triangle and bubble coefficients are equivalent to each other.  相似文献   
975.
976.
    
We have investigated the pressure-induced behaviors of nitrogen confined in the zero-dimensional cavities of zeolitic imidazolate framework (ZIF)-8 using Raman spectroscopy. Pressure forces the nitrogen molecules in the pressure-transmitting medium (PTM) to enter the inner pores of ZIF-8, and two Raman bands attributed to the nitrogen molecules interacting with the framework of ZIF-8 and those approximately in the central part of the cavities surrounded by the former are observed. The confined nitrogen species transform in a different way under high pressure from those of the bulk nitrogen and the confined nitrogen in the one-dimensional inorganic channels. Both the intermolecular interaction and the host–guest interaction jointly contribute to the transformation and a highly disordered and densely compressed state of the confined nitrogen is formed at 20 GPa. A hysteresis is found when comparing the Raman spectra at low and industrially accessible pressures after a compression and decompression cycle, suggesting that the ability of ZIF-8 to storage nitrogen molecules increases. This study opens a new path toward understanding new behaviors of nitrogen in the nanostate and applications of ZIF-8 for gas storage and capture.  相似文献   
977.
    
This study presents the microplasma direct writing of copper film in the open air using a novel copper powder electrode. The powder electrode acted as a high‐voltage electrode and the precursor source. The deposition process is realized through ion sputtering of the powder in the microplasma. The bombarded copper nanoparticles were deposited and accumulated on a silicon substrate. The deposited film is composed of copper nanoparticles with sizes in the range from tens to hundreds of nanometers, and its electrical conductivity could reach 3.96 × 105 S/m. The morphologies, chemical compositions and electrical property of the thin film can be adjusted by changing the input current, and maskless film deposition with different micropatterns can be achieved by direct microplasma scanning.  相似文献   
978.
979.
    
On the heels of exacerbating environmental concerns and ever-growing global energy demand, development of high-performance renewable energy-storage and -conversion devices has aroused great interest. The electrode materials, which are the critical components in electrochemical energy storage (EES) devices, largely determine the energy-storage properties, and the development of suitable active electrode materials is crucial to achieve efficient and environmentally friendly EES technologies albeit the challenges. Two-dimensional transition-metal chalcogenides (2D TMDs) are promising electrode materials in alkali metal ion batteries and supercapacitors because of ample interlayer space, large specific surface areas, fast ion-transfer kinetics, and large theoretical capacities achieved through intercalation and conversion reactions. However, they generally suffer from low electronic conductivities as well as substantial volume change and irreversible side reactions during the charge/discharge process, which result in poor cycling stability, poor rate performance, and low round-trip efficiency. In this Review, recent advances of 2D TMDs-based electrode materials for alkali metal-ion energy-storage devices with the focus on lithium-ion batteries (LIBs), sodium-ion batteries (SIBs), potassium-ion batteries (PIBs), high-energy lithium–sulfur (Li–S), and lithium–air (Li–O2) batteries are described. The challenges and future directions of 2D TMDs-based electrode materials for high-performance LIBs, SIBs, PIBs, Li–S, and Li–O2 batteries as well as emerging alkali metal-ion capacitors are also discussed.  相似文献   
980.
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