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991.
Rong J Lee LA Li K Harp B Mello CM Niu Z Wang Q 《Chemical communications (Cambridge, England)》2008,(41):5185-5187
Fibrillar M13 bacteriophages were used as basic building blocks to generate thin films with aligned nanogrooves, which, upon chemical grafting with RGD peptides, guide cell alignment and orient the cell outgrowth along defined directions. 相似文献
992.
993.
Xiaoqing Liu Wenxin Niu Haijuan Li Shuang Han Lianzhe Hu Guobao Xu 《Electrochemistry communications》2008,10(9):1250-1253
An electrochemiluminescent glucose biosensor was proposed based on gold nanoparticle-catalyzed luminol electrochemiluminescence (ECL). Gold nanoparticles were self-assembled onto silica sol–gel network, and then glucose oxidase was adsorbed on the surface of gold nanoparticles. The surface assembly process and the electrochemistry and ECL behaviors of the biosensor were investigated. The assembled gold nanoparticles could efficiently electrocatalyze luminol ECL. ECL intensity of the biosensor depended on scan rate, luminol concentration, and size of gold nanoparticles. The response of the ECL biosensor was linear over the range 1 μM to 5 mM with a detection limit of 0.2 μM glucose and showed satisfying reproducibility, stability and selectivity. 相似文献
994.
A simple detection method using ultra-performance liquid chromatography electrospray ionisation tandem mass spectrometry (UPLC-ESI-MS-MS) coupled with the sample dilution method for determining trace microcystin-LR (MC-LR) in drinking water is presented. The limit of detection (LOD) was 0.04 μg/L and the limit of quantitation (LOQ) was 0.1 μg/L. Water matrix effects of ionic strength, dissolved organic carbon (DOC) and pH were examined. The results indicate that signal detection intensity for MC-LR was significantly suppressed as the ionic strength increased from ultrapure water condition, whereas it increased slightly with solution pH and DOC at low concentrations. However, addition of methanol (MeOH) into the sample was able to counter the signal suppression effects. In this study, dilution of the tap water sample by adding 4% MeOH (v/v) was observed to be adequate to compensate for the signal suppression. The recoveries of the samples fortified with MC-LR (0.2, 1, and 10 μg/L) for three different tap water samples ranged from 84.4% to 112.9%. 相似文献
995.
A new type of chemically converted graphene sheets, cationic polyelectrolyte-functionalized ionic liquid decorated graphene sheets (PFIL-GS) composite, was synthesized and characterized by Ultraviolet-visible (UV-vis) absorption, Fourier transform infrared, and Raman spectroscopy. It was found that the presence of PFIL enabled the formation of a very stable aqueous dispersion due to the electrostatic repulsion between PFIL modified graphene sheets. With respect to the excellent dispersibility of this material, we have fabricated a novel PFIL-GS/Prussian blue (PB) nanocomposite multilayer film via classic layer-by-layer (LBL) assembly. The assembly process was confirmed by UV-vis spectroscopy and surface plasmon resonance (SPR) spectroscopy, which showed linear responses to the numbers of the deposited PFIL-GS/PB bilayers. Moreover, the as-prepared composite films were used to detect hydrogen peroxide (H2O2) by electrochemical surface plasmon resonance (EC-SPR) spectroscopy. This real time EC-SPR technique can provide simultaneous monitoring of both optical SPR signal and electrochemical current responses upon injecting H2O2 into the reaction cell. The experimental results revealed that both the electrochemical and SPR signal exhibited splendid linear relationship to the concentration of the injected H2O2, and the detection limit could be up to 1 μM. 相似文献
996.
997.
998.
Li S Zuo Z Niu D Singh S Permaul K Prior BA Shi G Wang Z 《Applied biochemistry and biotechnology》2011,164(5):581-592
A putative α-amylase gene, designated as RoAmy, was cloned from Rhizopus oryzae. The deduced amino acid sequence showed the highest (42.8%) similarity to the α-amylase from Trichoderma viride. The RoAmy gene was successfully expressed in Pichia pastoris GS115 under the induction of methanol. The molecular weight of the purified RoAmy determined by sodium dodecyl sulfate polyacrylamide
gel electrophoresis was approximately 48 kDa. The optimal pH and temperature were 4–6 and 60 °C, respectively. The enzyme
was stable at pH ranges of 4.5–6.5 and temperatures below 50 °C. Purified RoAmy had a K
m and V
max of 0.27 mg/ml and 0.068 mg/min, respectively, with a specific activity of 1,123 U/mg on soluble starch. Amylase activity
was strongly inhibited by 5 mM Cu2+ and 5 mM Fe2+, whereas 5 mM Ca2+ showed no significant effect. The RoAmy hydrolytic activity was the highest on wheat starch but showed only 55% activity
on amylopectin relative to soluble corn starch, while the pullulanase activity was negligible. The main end products of the
polysaccharides tested were glucose and maltose. Maltose reached a concentration of 74% (w/w) with potato starch as the substrate. The enzyme had an extremely high affinity (K
m = 0.22 mM) to maltotriose. A high ratio of glucose/maltose of 1:4 was obtained when maltotriose was used at an initial concentration
of 40 mM. 相似文献
999.
1000.
J. Li Y. Liu J. Luo J. W. Zhao P. T. Ma J. Y. Niu 《Russian Journal of Coordination Chemistry》2011,37(11):849-853
An interesting heptamolybdate (NH4)6H2[Cu(C2O4)2(Mo7O24)] · 9H2O (I) was prepared by convenational method in an aqueous solution and characterized by IR spectroscopy, elemental analysis, thermogravimetric
analysis, X-ray photoelectron spectroscopy and single-crystal X-ray diffraction. Crystal data for I: monoclinic, space group P21/m with a = 10.1460(5), b = 18.2616(9), c = 10.4994(5) ?, β = 94.3410(10)°, and Z = 2. X-ray structure analysis revealed the complexes to contain a copper center in an octahedral coordination mode bound
to two [C2O4]2− anios via the oxygen atoms and two oxygen atoms of the new heptamolybdate species. The zigzag chain structure of I is constructed by [Cu(C2O4)2(Mo7O24)] units via Mo-O-Cu-O-Mo linkers. 相似文献