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排序方式: 共有193条查询结果,搜索用时 31 毫秒
181.
182.
Adil Shafi Ganie Sayfa Bano Saima Sultana Suhail Sabir Mohammad Zain Khan 《Electroanalysis》2021,33(1):233-248
Development of nanocomposite based electrochemical sensors for detection of toxic chemicals describes an environmentally benign strategy for monitoring the health of ecosystem. Herein, we reported in situ preparation of graphitic carbon nitride (g-C3N4) decorated Ag2S/NiFe2O4 nanocomposite sensor by facile precipitation method. The electrochemical studies demonstrated efficient electrocatalytic activity of ternary nanocomposite pasted glassy carbon electrode (g-C3N4@Ag2S/NiFe2O4/GCE) for selective detection of formaldehyde. Moreover, fabricated sensor exhibit rapid amperometric response with excellent selectivity, remarkable sensitivity (1681 μA mmol L−1 cm−2) and lower detection limit (LOD: 1.63 μmol L−1). It is noteworthy to mention that sensor exhibits good operational and long-term storage stability. 相似文献
183.
Lobana TS Sultana R Butcher RJ 《Dalton transactions (Cambridge, England : 2003)》2011,40(43):11382-11384
2-Mercapto-1-methyl-imidazoline (N(2)C(4)H(6)S) is converted at room temperature into 2-bromo-1-methyl-imidazole (N(2)C(4)H(5)Br) in presence of copper(I) bromide in acetonitrile-chloroform mixture via extrusion of sulfur as sulfate and oxidation of Cu(I) into Cu(II). 2-Bromo-1-methyl-imidazole was isolated as its self assembled tetranuclear Cu(II) cluster, [Cu(4)(η(1)-N-(N(2)C(4)H(5)Br)(4)(μ(4)-O)(μ-Br)(6)] 1 {η(1)-N-(N(2)C(4)H(5)Br) = 2-bromo-1-methyl-imidazole}. 相似文献
184.
We apply the null-geodesic method to investigate tunneling radiation of charged and magnetized massive particles from Taub-NUT-Reissner-Nordström black holes endowed with electric as well as magnetic charges in Anti-de Sitter (AdS) spaces. The geodesics of charged massive particle tunneling from the black hole is not lightlike, but can be determined by the phase velocity. We find that the tunneling rate is related to the difference of Bekenstein-Hawking entropies of the black hole before and after the emission of particles. The entropy differs from just a quarter area at the horizon of black holes with NUT parameter. The emission spectrum is not precisely thermal anymore and the deviation from the precisely thermal spectrum can bring some information out, which can be treated as an explanation to the information loss paradox. The result can also be treated as a quantum-corrected radiation temperature, which is dependent on the black hole background and the radiation particle’s energy and charges. 相似文献
185.
In the present work, indigenous coal ash taken from Sharigh, Balochistan, Pakistan was used to prepare polymer electrolyte films with PEO/PMMA/LiClO4. Coal ash was first characterized by various techniques like Surface and Porosity Analysis, SEM/energy dispersive X-ray analysis (EDX), transmission electron microscopy, Fourier transform infrared (FTIR), and XRD. Chemical composition of ash was confirmed by EDX. Then, the utility of coal ash towards fabricating PEO/PMMA/LiClO4/coal ash composites was studied in order to explore its use as an additive for polymeric blend composites. The ash incorporation into the polymeric blend composites was studied by X-ray diffraction and UV/Visible spectroscopy, while ionic conductivity measurements were undertaken by Impedance spectroscopy. Room temperature conductivity of polymeric blend composites was found to increase sharply with ash content and reached maximum at 3.3 wt.% of ash. Both direct and indirect band gap energies of polymeric blend decreased with coal ash incorporation. The decrease was at peak at 3.3 wt.% of ash. Coal ash has found to improve the performance of polymeric blends. 相似文献
186.
Nagaraju M. Patro Azmi Sultana Keiji Terao Daisuke Nakata Ayako Jo Akihito Urano Yoshiyuki Ishida Raghu N. Gorantla Vinay Pandit Kshama Devi Shishir Rohit Baljinder K. Grewal Elizabeth M. Sophia Anand Suresh Vineeth K. Ekbote Sarasija Suresh 《Journal of inclusion phenomena and macrocyclic chemistry》2014,78(1-4):471-483
In the present study investigated the effect of curcumin (CUR) alpha (α), beta (β) and gamma (γ) cyclodextrin (CD) complexes on its solubility and bioavailability. CUR the active principle of turmeric is a natural antioxidant agent with potent anti-inflammatory activity along with chemotherapeutic and chemopreventive properties. Poor solubility and poor oral bioavailability are the main reasons which preclude CUR use in therapy. Extent of complexation was β-CD complex (82 %) > γ-CD (71 %) > α-CD (65 %). Pulverization method resulted in significant enhancement of CUR (0.002 mg/ml) solubility with CUR α-CD complex (0.364 mg/ml) > CUR β-CD complex (0.186 mg/ml) > CUR γ-CD complex (0.068 mg/ml). Gibbs-free energy and in silico molecular docking studies favour formation of α-CD complex > β-CD complex > γ-CD complex. With reference to CUR, relative bioavailability of CUR α-CD, CUR β-CD and CUR γ-CD complexes were 460, 365 and 99 % respectively. CUR–CD complexes exhibited increased bioavailability with an increase in t½, tmax, Cmax, AUC, Ka, and MRT; and a decrease in Ke, clearance and Vd values. AUC increase was CUR α-CD complex > CUR β-CD complex > CUR γ-CD complex. Significant difference (p < 0.05) was observed between CUR α-CD complex and CUR γ-CD complex by one-way ANOVA and Dunnett’s post hoc test for multiple comparison analysis. Correlation observed between in vitro, in vivo and in silico methods indicates potential of in silico and in vitro methods in CD selection. 相似文献
187.
Tarlok S. Lobana Prof. Renu Sharma Rekha Sharma Razia Sultana R. J. Butcher 《无机化学与普通化学杂志》2008,634(4):718-723
Reactions of divalent Zn‐Hg metal ions with 1,3‐imidazolidine‐2‐thione (imdtH2) in 1 : 2 molar ratio have formed monomeric complexes, [Zn(η1‐S‐imdtH2)2(OAc)2] ( 1 ), [Cd((η1‐SimdtH2)2I2] ( 2 ), [Cd(η1‐S‐imdtH2)2Br2] ( 3 ), and [Hg(η1‐S‐imdtH2)2I2] ( 4 ). Complexes 1 – 4 , have been characterized by elemental analysis (C, H, N), spectroscopy (IR, 1H, NMR) and x‐ray crystallography ( 1 ‐ 4 ). Hydrogen bonding between oxygen of acetate and imino hydrogen of ligand, {N(2)–H(2C)···O(2)#} in 1 , ring CH and imino hydrogen, {C(2A)–H(2A)···Br(2)#} in 3 have formed H‐bonded dimers. Similarly, the interactions between molecular units of complexes 2 and 4 have yielded 2D polymers. The polymerization occurs via intermolecular interactions between thione sulfur and imino hydrogen, {N(2)–H(2)···S(1)#}, imino hydrogen and the iodine atom, {NH(1)···I(2)#} in 2 and imino hydrogen – iodine atom {N(2A)–H(2A)···I(2)} and I···I interaction in 4 . Crystal data: [Zn(η1‐S‐imdtH2)2(OAc)2] ( 1 ), C10H18N4O4S2Zn, orthorhombic, Pbcn, a = 9.3854(7) Å, b = 12.4647(10) Å, c = 13.2263(11) Å; V = 1547.3(2) Å3, Z = 4, R = 0.0280 [Cd((η1‐S‐imdtH2)2I2] ( 2 ), C6H12CdI2N4S2, orthorhombic, Pnma, a = 13.8487(10) Å, b = 14.4232(11) Å, c = 7.0659(5) Å; Z = 4, V = 1411.36(18) Å3, R = 0.0186. 相似文献
188.
Aerial parts of Skimmia laureola yielded a new fatty ester, (+)-skimmilaureol (1), and a new triterpene 16-29-dihydroxy, 20-ene cyclolaudenol (2). Five known compounds, namely, O-methyl-cyclolaudenol (3), (R)-7-methoxy-6-(3'-hydroxy-2'R-methoxy-3'-methyl butyl)coumarin (4), (+)-(S)-psi-ribalinine (5), (R)-(+)-ribalinine (6) and methyl isoplatydesmine (7), previously isolated from this plant were subjected to enzymatic bioassays for the first time. Compounds 3 and 4 were found to be prolyl endopeptidase inhibitors with IC(50) 8.21 +/- 0.407 and 39.63 +/- 1.502 microM, respectively, while compounds 5-7 were found to be acetyl-cholinesterase and butyryl-cholinesterase inhibitors with IC(50) 62.46 +/- 1.58, 153.31 +/- 1.9, 74.5 +/- 1.05 and 150.04 +/- 0.45, 12.99 +/- 0.31, 78.3 +/- 1.86 microM, respectively. 相似文献
189.
Variation in antioxidant attributes at three ripening stages of guava (Psidium guajava L.) fruit from different geographical regions of Pakistan 总被引:1,自引:0,他引:1
Gull J Sultana B Anwar F Naseer R Ashraf M Ashrafuzzaman M 《Molecules (Basel, Switzerland)》2012,17(3):3165-3180
The present investigation was carried out to appraise the levels of total phenols and vitamin C as well as antioxidant potential at three different ripening stages (un-ripe, semi-ripe and fully-ripe) of guava (Psidium guajava L.) fruit collected from three different geographical regions of Pakistan (Islamabad, Faisalabad and Bhakkar). The antioxidant potential of guava fruit extracts was assessed by means of different in-vitro antioxidant assays, namely inhibition of peroxidation in linoleic acid system, reducing power and radical scavenging capability. Overall, fruit at the un-ripe stage (G1) exhibited the highest levels of TPC, TFC, reducing power and DPPH radical scavenging activity, followed by the semi-ripe (G2) and fully-ripe (G3) stages. On the other hand, vitamin C content increased as the fruit maturity progressed, with highest value seen at the fully-ripe stage (G3) followed by the semi-ripe (G2) and un-ripe stage (G1). The concentration of vitamin C in fruits varied as: Faisalabad (136.4-247.9 mg 100 g?1), Islamabad (89.7-149.7 mg 100 g?1) and Bhakkar (73.1-129.5 mg 100 g?1). The results showed that different stages of maturation and geographical locations had profound effects on the antioxidant activity and vitamin C contents of guava fruit. 相似文献
190.
In this paper we develop a non-polynomial quintic spline function to approximate the solution of third order linear and non-linear
boundary value problems associated with odd-order obstacle problems. Such problems arise in physical oceanography and can
be studied in the framework of variational inequality theory. The class of methods are second and fourth order convergent.
End equations of the splines are derived and truncation error is obtained. Two numerical examples are given to illustrate
the applicability and efficiency of proposed method. It is shown that the new method gives approximations, which are better
than those produced by other methods. 相似文献