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191.
This paper presents a tunable hybrid brillouin-erbium fiber laser system with a maximum tuning range of more than 36.7 nm. The system was configured in a ring set-up with another fiber laser used as the brillouin pump at about 8 mW maximum launched power. Stable Stokes signals at an average of about 0.08 nm wavelength shift were observed across the tuning range. The dependency of the Stokes signal tuning range on the laser's spectral gain is also elaborated.  相似文献   
192.
Since the adult mammalian heart has limited regenerative capacity, cardiac trauma, disease, and aging cause permanent loss of contractile tissue. This has fueled the development of stem cell-based strategies to provide the damaged heart with new cardiomyocytes. Bone marrow-derived mesenchymal stem cells (BM-MSCs) are capable of self-renewal and differentiation into cardiomyocytes, albeit inefficiently. MicroRNAs (miRNAs, miRs) are non-coding RNAs that have the potential to control stem cell fate decisions and are employed in cardiac regeneration and repair. In this study, we tested the hypothesis that overexpression of miR-499a induces cardiomyogenic differentiation in BM-MSCs. Human BM-MSCs (hBM-MSCs) were transduced with lentiviral vectors encoding miR-499a-3p or miR-499a-5p and analyzed by immunostaining and western blotting methods 14 days post-transduction. MiR-499a-5p-transduced cells adopted a polygonal/rod-shaped (myocyte-like) phenotype and showed an increase in the expression of the cardiomyocyte markers α-actinin and cTnI, as cardiogenic differentiation markers. These results indicate that miR-499a-5p overexpression promotes the cardiomyogenic differentiation of hBM-MSCs and may thereby increase their therapeutic efficiency in cardiac regeneration.  相似文献   
193.
The antioxidant activities of crude extract fractions using Hexane, Chloroform, Ethyl Acetate, Butanol and Water of Clematis orientalis and Clematis ispahanica were investigated. 1,1-diphenyl-2-picryl-hydrazyl (DPPH) assay and the ferric reducing/antioxidant potential (FRAP) were used to evaluate the antioxidant capacity. The total phenolics were found to be 4.37–9.38 and 1.32–11.37 mg gallic acid equivalents (GAE)/g in different fractions for C. orientalis and C. ispahanica, respectively. The ethyl acetate fraction of C. orientalis and chloroform fraction of C. ispahanica showed the highest DPPH and FRAP activities at a concentration of 300 μg/mL. The predominant phenolic compounds identified by HPLC in C. orientalis were Resorcinol (603.5 μg/g DW) in chloroform fraction and Ellagic acid (811.7 μg/g DW) in chloroform fraction of C. ispahanica.  相似文献   
194.
In this paper, we introduced pyridinyl benzimidazol (PBI) as an easy-to-handle and bidentate N-chelating ligand that promote clean synthesis of 3,5-disubstituted isoxazoles in the presence of copper acetate as catalyst. This catalytic approach initiates with the hydroxyamination of aldehydes followed by chlorination and then generation of nitrile oxide which subsequently undergoes click-type [3 + 2]-dipolar cycloaddition with alkynes to give isoxazoles. This method provides an alternative green process to construct isoxazole derivatives.  相似文献   
195.
196.
The aim of the recent research was to investigate the anti-breast cancer effects of silver nanoparticles using Phoenix dactylifera seed ethanolic extract (AgNPs). After preparation of Phoenix dactylifera seed extract, GC/MS was performed to detect the compounds. The findings indicated that 9-Octadecenoic acid (Z)- methyl ester (40.95%) and Dodecanoic acid methyl ester (20%) were the most frequent constituents found in P. dactylifera. These nanoparticles were spherical with a size range of 17-19 nm and characterized using various analytical techniques including UV–Vis absorption spectroscopy to determine the presence of AgNPs in the solution. We studied functional groups of P. dactylifera extract in the reduction and capping process of AgNPs by FT-IR, crystallinity and FCC planes by X-ray diffraction (XRD) pattern and surface morphology, shapes, and size of AgNPs by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). DPPH free radical scavenging test was used to test the antioxidant properties of P. dactylifera and AgNPs, which revealed high antioxidant potential similar to butylated hydroxy toluene (BHT) as the positive control. The results of cytotoxicity analysis indicated that P. dactylifera and AgNPs were toxic for MCF-7 cells. In vivo design, induction of breast cancer was done by 7,12-Dimethylbenz[a] anthracene (DMBA) in 50 animals. After 10 days, the animals were randomly divided into six subgroups, including healthy control, untreated control, two groups receiving the P. dactylifera at 2 and 6 mg/kg and two groups receiving the AgNPs at 2 and 6 mg/kg concentrations. Both doses of P. dactylifera and AgNPs (especially AgNPs6) significantly (p ≤ 0.05) reduced the weight and volume of liver, mammary gland, kidney, spleen, ALP, AST, ALT, GGT, cholesterol, LDL, triglyceride, total and conjugated bilirubin, urea, creatinine, glucose, ferrous, ferritin, erythropoietin, GR, IL1, IL6, IL12, IL18, IFNY, and TNFα and increased HDL, total protein, albumin, WBC, lymphocyte, neutrophils, platelet, RBC, Hb, PCV, MCV, MCH, MCHC, SOD, CAT, GPx, IL4, IL5, IL10, IL13, and IFNα compared to the untreated group. Moreover, P. dactylifera and AgNPs (especially AgNPs6) significantly (p ≤ 0.05) treated breast cancer with reduction of organs free of metastasis compared to the untreated group. Seemingly, the AgNPs can be used for the treatment of breast cancer.  相似文献   
197.
Nanobiotechnology is a capable technology that deals with nanomaterials in several scientific domains such as medicine, chemistry, nanotechnology, and biotechnology. In this scale, remarkable differences are seen in many properties of materials that are not observed on a larger scale. In this regard, pharmacologists have tried to synthesize many supplements and drugs from the nanoparticles. The present study confirms the ability of aqueous extract of Hibiscus sabdariffa grown under in vitro condition for the biosynthesis of gold nanoparticles (AuNPs). Also, in this study, we revealed the anti-acute myeloid leukemia activity of AuNPs compared to daunorubicin in a leukemic rodent model. These nanoparticles were characterized by fourier-transform infrared spectroscopy (FT-IR) spectroscopy, ultraviolet–visible spectroscopy (UV–Vis.), X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), and transmission electron microscopy (TEM) analysis. TEM and FE-SEM images exhibited a uniform spherical morphology and diameters of 15-45 nm for the biosynthesized nanoparticles. In vivo design, induction of acute myeloid leukemia was done by 7,12-Dimethylbenz[a]anthracene (DMBA) in 75 mice. Then, the animals were randomly divided into six subgroups, including HAuCl4, H. sabdariffa, AuNPs, daunorubicin, untreated, and control. AuNPs similar to daunorubicin, significantly (P ≤ .05) reduced the pro-inflammatory cytokines (IL1, IL6, IL12, IL18, IFNY, and TNFα), and the total white blood cell (WBC), blast, monocyte, neutrophil, eosinophil, and basophil counts and enhanced the anti-inflammatory cytokines (IL4, IL5, IL10, IL13, and IFNα) and the platelet, lymphocyte, and red blood cell (RBC) parameters as compared to the untreated mice. By quantitative real-time polymerase chain reaction, sphingosine-1-phosphate receptor-1 and sphingosine-1-phosphate receptor-5 mRNA expression in lymphocytes were significantly (P ≤ .05) raised by treating the leukemic mice with the AuNPs and daunorubicin. In vitro design, 2,2-diphenyl-1-picrylhydrazyl (DPPH) test revealed similar antioxidant potentials for daunorubicin and AuNPs. Besides, AuNPs similar to daunorubicin had low cell viability dose-dependently against Murine C1498, Human HL-60/vcr, and 32D-FLT3-ITD cell lines without any cytotoxicity on HUVEC cell line. In conclusion, the results of chemical characterization confirm that the H. sabdariffa flower can be used to produce gold nanoparticles with a remarkable amount of anti-acute myeloid leukemia effect.  相似文献   
198.
Journal of Radioanalytical and Nuclear Chemistry - In the current study, dose rate and photon energy dependence of PASSAG gel dosimeter is evaluated by using MRI technique. The gel samples were...  相似文献   
199.
Polymerization of 1‐hexene was carried out using a mononuclear (MN) catalyst and two binuclear (BN1 and BN2) α‐diimine Ni‐based catalysts synthesized under controlled conditions. Ethylaluminium sesquichloride (EASC) was used as an efficient activator under various polymerization conditions. The highly active BN2 catalyst (2372 g poly(1‐hexene) (PH) mmol?1 cat) in comparison to BN1 (920 g PH mmol?1 cat) and the MN catalyst (819 g PH mmol?1 cat) resulted in the highest viscosity‐average molecular weight (Mv) of polymer. Moreover, the molecular weight distribution (MWD) of PH obtained using BN2/EASC was slightly broader than those obtained using BN1 and MN (2.46 for BN2 versus 2.30 and 1.96 for BN1 and MN, respectively). These results, along with the highest extent of chain walking for BN2, were attributed to steric, nuclearity and electronic effects of the catalyst structures which could control the catalyst behaviour. Differential scanning calorimetry showed that the glass transition temperatures of polymers were in the range ? 58 to ?81 °C, and broad melting peaks below and above 0 °C were also observed. In addition, longer α‐olefins (1‐octene and 1‐decene) were polymerized and characterized, for which higher yield, conversion and molecular weight were observed with a narrower MWD. The polymerization parameters such as polymerization time and polymerization temperature showed a significant influence on the productivity of the catalysts and Mv of samples.  相似文献   
200.
Present study used ecofriendly, cost efficient and easy method for synthesis of silver nanoparticles (Ag NPs) at the room temperature by Thymus Kotschyanus extract as reducing and capping agent. Various analytical technique including UV–Vis absorption spectroscopy determined presence of Ag NPs in the solution, the functional groups of Thymus Kotschyanus extract in the reduction and capping process of Ag NPs are approved by FT‐IR, crystallinity with the fcc plane approved from the X‐ray diffraction (XRD) pattern, energy dispersive spectroscopy (EDS) determined existence of elements in the sample, surface morphology, diverse shapes and size of present Ag NPs were showed by using scanning electron microscopy (SEM), atomic force microscopy (AFM) and high resolution transmission electron microscopy (HRTEM). Beginning and end destroy temperature of present silver nanoparticles were determined by thermal gravimetric spectroscopy (TGA). In addition, antibacterial, antioxidant and cytotoxicity properties of Ag NPs were studied. Agar disk and agar well diffusion are the methods to determined antibacterial properties of synthesized Ag NPs. Also MIC (Minimum Inhibitory Concentration) and MBC (Minimum Bactericidal Concentration) were recognized by macro broth dilution assay. DPPH free radical scavenging assay was used for antioxidant property and compare to butylated hydroxytoluene (BHT) as standard antioxidant that showed high antioxidant activity more than BHT. Synthesized Ag NPs have great cell viability in a dose depended manner and demonstrate that this method for synthesis silver nanoparticles provided nontoxic. The average diameter of synthesized Ag NPs was about 50–60 nm.  相似文献   
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