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461.
Tin diselenide single crystals have been grown by the physical vapour transport (PVT) method. Optical absorption studies give an indirect allowed transition at 1.03 eV at room temperature. The electrical resistivity parallel and perpendicular to c-axis, mobility and carrier concentration have been determined. Dependence of resistivity parallel to c-axis on temperature gives an activation energy of 0.072 eV. Growth spirals observed for the first time on the as grown faces of these crystals are also presented here.  相似文献   
462.
Curcumin (CUR) has been studied for its biomedical applications due to its active biological properties. However, CUR has limitations such as poor solubility, low bioavailability, and rapid degradation. Thus, CUR was nanoformulated with the application of polymeric micelle. Previous studies of CUR-loaded Pluronic F127 nanoformulation (NanoCUR) were generally prioritized toward cancer cells and its therapeutic values. There are reports that emphasize the toxicity of CUR, but reports on the toxicity of NanoCUR on embryonic developmental stages is still scarce. The present study aims to investigate the toxicity effects of NanoCUR on the embryonic development of zebrafish (Danio rerio). NanoCUR was synthesized via thin film hydration method and then characterized using DLS, UV-Vis, FTIR, FESEM, and XRD. The toxicity assessment of NanoCUR was conducted using zebrafish embryos, in comparison to native CUR, as well as Pluronic F127 (PF) as the controls, and ROS assay was further carried out. It was revealed that NanoCUR showed an improved toxicity profile compared to native CUR. NanoCUR displayed a delayed toxicity response and showed a concentration- and time-dependent toxicity response. NanoCUR was also observed to generate a significantly low reactive oxygen species (ROS) compared to native CUR in ROS assay. Overall, the results obtained highlight the potential of NanoCUR to be developed in clinical settings due to its improved toxicity profile compared to CUR.  相似文献   
463.
A numerical scheme is constructed for the problems in which the diffusion and convection parameters (?1 and ?2 , respectively) both are small, and the convection and source terms have a jump discontinuity in the domain of consideration. Depending on the magnitude of the ratios , and two different cases have been considered separately. Through rigorous analysis, the theoretical error bounds on the singular and regular components of the solution are obtained separately, which shows that in both cases the method is convergent uniformly irrespective of the size of the parameters ?1, ?2 . Two test problems are included to validate the theoretical results.  相似文献   
464.
Urinary tract infections (UTIs) are considered to be the most common infections worldwide, having an incidence rate of 40−60% in women. Moreover, the prevalence of this disorder in adult women is 30 times more than in men. UTIs are usually found in many hospitals and clinical practice; as disorders, they are complicated and uncomplicated; in uncomplicated cases, there is no structural or functional abnormality in the urogenital tract. However, obstruction, retention of urine flow and use of catheters increase the complexity. There are several bacteria (e.g., E. coli, Klebsiella pneumoniae, Proteus vulgaris, etc.) successfully residing in the tract. The diagnosis must not only be accurate but rapid, so early detection is an important step in the control of UTIs caused by uropathogens. The treatment of UTIs includes appropriate antimicrobial therapy to control the infection and kill the causal microbes inside the body. A long-time usage of antibiotics has resulted in multidrug resistance causing an impediment in treatment. Thus, alternative, combinatorial medication approaches have given some hope. Available treatments considered Homeopathic, Ayurvedic, Unani, and other herbal-based drugs. There are new upcoming roles of nanoparticles in combating UTIs which needs further validation. The role of medicinal plant-based nanotechnology approaches has shown promising results. Therefore, there must be active research in phyto-based therapies of UTIs, such as Ayurvedic Biology.  相似文献   
465.
A nonsimilar boundary layer analysis is presented for the problem of mixed convection in power-law type non-Newtonian fluids along a vertical plate with power-law surface heat flux distribution. The mixed convection regime is divided into two regions, namely, the forced convection dominated regime and the free convection dominated regime. The two solutions are matched. Numerical results are presented for the details of the velocity and temperature fields. A discussion is provided for the effect of viscosity index on the surface heat transfer rate. Received on 13 October 1998  相似文献   
466.
Aphis craccivora Koch is a polyphagous and major pest of leguminous crops causing significant damage by reducing the yield. Repeated application of synthetic insecticides for the control of aphids has led to development of resistance. Therefore, the present study aimed to screen the insecticidal activity of root/stem extracts/fractions, and pure molecules from Cissampelos pareira Linnaeus against A. craccivora for identification of lead(s). Among root extract/fractions, the n-hexane fraction was found most effective (LC50 = 1828.19 mg/L) against A. craccivora, followed by parent extract (LC50 = 2211.54 mg/L). Among stem extract/fractions, the n-hexane fraction (LC50 = 1246.92 mg/L) was more effective than the water and n-butanol fractions. Based on GC and GC-MS analysis, among different compounds identified in the n-hexane fraction of root and stem, ethyl palmitate (known to possess insecticidal activity) was present in the highest concentration (24.94 to 52.95%) in both the fractions. Among pure molecules, pareirarineformate was found most effective (LC50 = 1491.93 mg/L) against A. craccivora, followed by cissamine (LC50 = 1556.31 mg/L). Parent extract and fractions of C. pareira possess promising activity against aphid. Further, field bio-efficacy studies are necessary to validate the current findings for the development of botanical formulation.  相似文献   
467.
468.
Abstract

One of the highly emerging and an important aspect of organic chemistry is the metal and organo-complex promoted synthesis of the heterocycles. The methodologies used earlier for its synthesis were less approachable to the organic chemist due to their high cost, highly sophisticated instrumentation and problematic methods. For both stereoselective and regioselective synthesis of fused five-membered O-containing heterocycles, cyclic reactions that are metal and organo-complex promoted have been known to be very efficient. The present review article covers the different applications of metals and organo-complexes in the formation of fused five-membered oxygen containing fused heterocycles. The fascinating research that has been done in this area is enclosed in this review.  相似文献   
469.
Journal of Sol-Gel Science and Technology - Highly crystalline nanotubes/nanoplates of pure and Ag-doped anatase-titania (TiO2) having high aspect-ratio have been synthesized, without the...  相似文献   
470.
A combined experimental and quantum chemical study of Group 7 borane, trimetallic triply bridged borylene and boride complexes has been undertaken. Treatment of [{Cp*CoCl}2] (Cp*=1,2,3,4,5‐pentamethylcyclopentadienyl) with LiBH4 ? thf at ?78 °C, followed by room‐temperature reaction with three equivalents of [Mn2(CO)10] yielded a manganese hexahydridodiborate compound [{(OC)4Mn}(η6‐B2H6){Mn(CO)3}2(μ‐H)] ( 1 ) and a triply bridged borylene complex [(μ3‐BH)(Cp*Co)2(μ‐CO)(μ‐H)2MnH(CO)3] ( 2 ). In a similar fashion, [Re2(CO)10] generated [(μ3‐BH)(Cp*Co)2(μ‐CO)(μ‐H)2ReH(CO)3] ( 3 ) and [(μ3‐BH)(Cp*Co)2(μ‐CO)2(μ‐H)Co(CO)3] ( 4 ) in modest yields. In contrast, [Ru3(CO)12] under similar reaction conditions yielded a heterometallic semi‐interstitial boride cluster [(Cp*Co)(μ‐H)3Ru3(CO)9B] ( 5 ). The solid‐state X‐ray structure of compound 1 shows a significantly shorter boron–boron bond length. The detailed spectroscopic data of 1 and the unusual structural and bonding features have been described. All the complexes have been characterized by using 1H, 11B, 13C NMR spectroscopy, mass spectrometry, and X‐ray diffraction analysis. The DFT computations were used to shed light on the bonding and electronic structures of these new compounds. The study reveals a dominant B?H?Mn, a weak B?B?Mn interaction, and an enhanced B?B bonding in 1 .  相似文献   
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