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991.
Muhammad Altaf Helen Stoeckli-Evans Saeed Ahmad Anvarhusein A. Isab Abdul Rahman Al-Arfaj Muhammad Riaz Malik Saqib Ali 《Journal of chemical crystallography》2010,40(12):1175-1179
Abstract
The title compound was prepared by reacting mercury(II) cyanide and tetramethylthiourea (Tmtu) in the molar ratio of 1:1.75. It was characterized by IR and NMR (1H and 13C) spectroscopy, and X-ray crystallography. The appearance of a band around 2,200 cm−1 in IR and a resonance around 145 ppm in 13C NMR indicated the binding of cyanide to mercury(II). The crystal structure of the title complex, [{(tetramethylthiourea)2Hg(CN)2}2·Hg(CN)2] (1) consists of two independent [(Tmtu)2Hg(CN)2] moieties bridged by a Hg(CN)2 unit. The mercury atom in [(Tmtu)2Hg(CN)2] unit is coordinated to two thione sulfur atoms of Tmtu and to two cyanide carbon atoms in a distorted tetrahedral mode. 相似文献992.
Shafqat Nadeem Muhammad Khawar Rauf Michael Bolte Saeed Ahmad Syed Ahmed Tirmizi Maliha Asma Abdul Hameed 《Transition Metal Chemistry》2010,35(5):555-561
Palladium(II) bromide complexes of thioamides having the general formulae [PdL2Br2] and [PdL4]Br2 where L = Thiourea (Tu), Methylthiourea (Metu), Dimethylthiourea (Dmtu), Tetramethylthiourea (Tmtu), Imidazolidine-2-thione
(Imt), Mercaptopyridine (Mpy), Mercaptopyrimidine (Mpm) and Thionicotinamide (Tna) were prepared by reacting K2[PdCl4] with KBr and the corresponding thioamides. The complexes were characterized by elemental analysis, IR and NMR spectroscopy,
and one of them, [Pd(Tmtu)4]Br2 (1) by X-ray crystallography. The crystal structure of 1 shows a square-planar coordination environment around the Pd(II) atoms with the average cis and trans S–Pd–S bond angles of 90.0° and 180.0°, respectively. The synthesized complexes were screened for antibacterial effects,
and the results showed that the complexes exhibit significant activities against both gram positive and gram negative bacteria. 相似文献
993.
The [4+2] cycloaddition of 3‐(arylsulfanyl)‐1‐(trimethylsilyloxy)buta‐1,3‐dienes with dimethyl penta‐2,3‐dienedioate provides a convenient and regioselective approach to a variety of 4‐(arylsulfanyl)‐2‐hydroxyhomophthalates. 相似文献
994.
Muhammad Imran Malik Bernd Trathnigg Karin Bartl Robert Saf 《Analytica chimica acta》2010,658(2):217-8378
Polyoxyalkylene diblock copolymers (consisting of PEO as hydrophilic block and PBO or PHO as hydrophobic block) are characterized by combination of two dimensional liquid chromatography and MALDI-TOF-MS. Liquid chromatography under critical conditions (LCCC) is used as first dimension and fractions are collected, mobile phase evaporated and diluted in the mobile phase used in the second dimension (SEC, LCCC or LAC). This two-dimensional chromatography in combination of MALDI-TOF-MS gives information about purity of reaction products, presence of the byproducts, chemical composition and molar mass distribution of all the products. 相似文献
995.
Olesya Myakonkaya Dr. Zhiyong Hu Muhammad Faizan Nazar Prof. Julian Eastoe 《Chemistry (Weinheim an der Bergstrasse, Germany)》2010,16(39):11784-11790
The stability and separation of colloids and nanoparticles has been addressed in numerous studies. Most of the work reported to date requires high cost, energy intensive approaches such as ultracentrifugation and solvent evaporation to recover the particles. At this point of time, when green science is beginning to make a real impact, it is vital to achieve efficient and effective separation and recovery of colloids to provide environmental and economic benefits. This article explores recent advances in strategies for recycling and reusing functional nanomaterials, which indicate new directions in lean engineering of high‐value nanoparticles, such as Au and Pd. 相似文献
996.
Afzal Shah Muhammad Zaheer Rumana Qureshi Zareen Akhter Muhammad Faizan Nazar 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2010,75(3):1082-1087
Cyclic voltammetry (CV) coupled with UV–vis and fluorescence spectroscopy were used to probe the interaction of potential anticancer drug, 4-nitrophenylferrocene (NFC) with DNA. The electrostatic interaction of the positively charged NFC with the anionic phosphate of DNA was evidenced by the findings like negative formal potential shift in CV, ionic strength effect, smaller bathochromic shift in UV–vis spectroscopy, incomplete quenching in the emission spectra and decrease in viscosity. The diffusion coefficients of the free and DNA bound forms of the drug were evaluated from Randles–Sevcik equation. The binding parameters like binding constant, ratio of binding constants (Kred/Kox), binding site size and binding free energy were determined from voltammetric data. The binding constant was also determined from UV–vis and fluorescence spectroscopy with a value quite close to that obtained from CV. 相似文献
997.
Afzal Shah Victor C. Diculescu Niaz Muhammad Rumana Qureshi Saqib Ali Ana Maria Oliveira‐Brett 《Electroanalysis》2010,22(1):121-127
The electrochemical behavior of Na‐salt of 2‐methyl‐3‐(4‐nitrophenyl)acrylate (NPA) and its reduction product was studied by cyclic (CV), differential pulse(DPV) and square wave voltammetry (SWV) using a glassy carbon electrode (GCE). The results revealed that NPA is irreversibly reduced leading to the formation of a reduction product (PNPA). For pH<9.0 the peak potential was linearly dependent on pH. For pH>9.0 the peak potential was pH‐independent and the value of pKb≈9.0 was determined. The adsorbed PNPA exhibited reversible redox reaction. The reduction of PNPA was pH dependent. To ensure that the electrochemical behavior of NPA is due to the reducible moiety, NO2, closely related compounds to NPA were also studied, and a redox mechanism was proposed for NPA. 相似文献
998.
Muhammad Irfan Ashiq Ishtiaq Hussain Sally Dixon Mark E. Light Jeremy D. Kilburn 《Acta Crystallographica. Section C, Structural Chemistry》2010,66(9):o455-o458
The structures of N‐benzyl‐N′‐{6‐[(4‐carboxylatobenzyl)aminocarbonyl]‐2‐pyridylmethyl}guanidinium, C23H23N5O3, (I), and N‐[2‐(benzylaminocarbonyl)ethyl]‐N′‐{6‐[(4‐carboxylatobenzyl)aminocarbonyl]‐2‐pyridylmethyl}guanidinium monohydrate, C26H28N6O4·H2O, (II), both form three‐dimensional supramolecular hydrogen‐bonded networks based on a dimeric primary synthon involving carboxylate–guanidinium linkages. The differences in the geometries and hydrogen‐bonding connectivities are driven by the additional methylpropionamide group and water of crystallization of (II). 相似文献
999.
Optical fibers of 12 μm diameter were coated with a sputter-deposited layer (4 μm thick) of titanium (1 at. %)-doped amorphous aluminum nitride. When optically pumped by an Nd:YAG green laser at 532 nm, laser action was observed in whispering gallery modes around the fiber (in a ring shape) at 780.5 nm with a quality factor Q > 1500. Other modes were also observed between 775 and 800 nm. The primary and secondary modes give a mode separation of 4.6 nm. No waveguide modes were observed in the cavity. 相似文献
1000.
Abdul Niaz Jan Fischer Jiří Barek Bogdan Yosypchuk Sirajuddin Muhammad Iqbal Bhanger 《Electroanalysis》2009,21(16):1786-1791
A differential pulse voltammetric (DPV) method was developed for the determination of 4‐nitrophenol (4‐NP) at a newly developed silver amalgam paste electrode (AgA‐PE) in Britton–Robinson buffer pH 3.0. The electrode is based on a disposable plastic pipette tip filled with paste amalgam based on a mixture of mercury and fine silver powder (9 : 1, w/w). The experimental parameters, such as pH of Britton–Robinson buffer and activation and regeneration potential of the electrode surface were optimized. The reduction peak current dependences were linear for the concentration of 4‐NP from 0.2 to 100 μM. The method showed reproducible results with RSD (n=45) of 1.7%. The limit of determination (LOD) was 0.3 μM. The method was successfully applied for the direct determination of 4‐NP in drinking water. 相似文献