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991.
Rapid liquid chromatographic procedures are proposed for analysis of paracetamol and orphenadrine citrate in pharmaceutical preparations and human serum using acetonitrile: water (50:50) as a mobile phase, adjusting pH to 2.6, UV detection at 215 nm and propylparaben sodium as internal standard. The advantages of this method include good and rapid separation, well resolved peaks, and only a small amount of sample is required for assay and adequate precision. The method showed good linearity in the range of 6 to 10000 ng/mL for paracetamol serum concentrations with a correlation coefficient 0.9999 (inter and intra day CV < 3.15) and in the range 3–10000 ng/mL for orphenadrine citrate serum concentrations with a correlation coefficient of 0.9999 (inter and intra day CV < 3.58). The recovery of paracetamol and orphenadrine citrate was > 96.9% and > 96.7%, respectively. The proposed method may be used for the quantitative analysis of paracetamol and orphenadrine citrate alone or in combination from raw materials, in bulk drugs, dosage formulations and in serum. 相似文献
992.
993.
Ca-doped ceria (CDC)/tabular titanate (K0.8Li0.27Ti1.73O4, TT) UV-shielding functional nanocomposite with fairly uniform CDC coating layers was prepared through a polyelectrolyte-associated layer-by-layer (LbL) coating method. TT with lepidocrocite-like layered structure was used as the substrate, poly (diallyldimethylammonium chloride) (PDDA) was used as a coupling agent, CDC nanoparticles were used as the main UV-shielding component. CDC/TT nanocomposites with various coating layers of CDC were obtained through a multistep coating process. The phases were studied by X-ray diffraction. The morphology and coating quality were studied by scanning electron microscopy and element mapping of energy dispersive X-ray analysis. The oxidation catalytic activity, UV-shielding ability and using comfort were characterized by Rancimat test, UV-vis spectra and dynamic friction test, respectively. CDC/TT nanocomposites with low oxidation catalytic activity, high UV-shielding ability and good using comfort were finally obtained. 相似文献
994.
995.
Tatsuya Sasano Hiromitsu Sogawa Kosaku Tamura Masashi Shiotsuki Toshio Masuda Fumio Sanda 《Journal of polymer science. Part A, Polymer chemistry》2010,48(8):1815-1821
Novel conjugated polymers containing 3,9‐carbazolylene and silylenevinylene moieties were synthesized by the hydrosilylation polymerization of 1,4‐bis(3‐ethynyl‐9‐carbazolyl)benzene ( 1 ) with various bis(hydrosilane)s or dihydrosilanes using a rhodium catalyst. Polymers with weight‐average molecular weights ranging from 5400 to 20,000 were obtained in 55–97% yields by the polyaddition with a rhodium catalyst in toluene at 25 °C for 24 h. All the polymers were soluble in CHCl3 and THF, and had predominantly trans‐structures. The polymers exhibited λmax at a longer wavelength region than 1 , and emitted fluorescence in 14–50% quantumn yields. The polymers were oxidized and reduced in the region of 0.4–1.6 V, and thermally stable up to 200 °C under air. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 1815–1821, 2010 相似文献
996.
Xiao‐Hui Liu Gui‐Bao Zhang Bai‐Xiang Li Yun‐Gang Bai Yue‐Sheng Li 《Journal of polymer science. Part A, Polymer chemistry》2010,48(23):5439-5445
Cu(0)‐mediated living radical polymerization was first extended to acrylonitrile (AN) to synthesize polyacrylonitrile with a high molecular weight and a low polydispersity index. This was achieved by using Cu(0)/hexamethylated tris(2‐aminoethyl)amine (Me6‐TREN) as the catalyst, 2‐bromopropionitrile as the initiator, and dimethyl sulfoxide (DMSO) as the solvent. The reaction was performed under mild reaction conditions at ambient temperature and thus biradical termination reaction was low. The rapid and extensive disproportionation of Cu(I)Br/Me6‐TREN in DMSO/AN supports a mechanism consistent with a single electron transfer‐living radical polymerization (SET‐LRP) rather than activators generated by electron transfer atom transfer radical polymerization (AGET ATRP). 1H NMR analysis and chain extension experiment confirm the high chain‐end functionality of the resultant polymer. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010 相似文献
997.
Eagambaram Murugan Rajmohan Rangasamy 《Journal of polymer science. Part A, Polymer chemistry》2010,48(12):2525-2532
We report here, the synthesis of two types of heterogeneous nanoparticle catalysts viz., polymer‐supported poly(propyleneimine)‐G2 dendrimer stabilized gold nanoparticle catalysts using crosslinked poly(4‐vinylpyridine) matrix (PSP4VP) as support material. The grafting of dendrimer on the surface of P4VP beads was characterized by FTIR spectrophotometer and CHN analyses. The immobilization of AuNPs was characterized by UV‐Vis spectrum, SEM, and HRTEM studies. The resultant polymer‐supported dendrimer stabilized AuNPs were used as a heterogeneous catalyst for the reduction of 4‐nitrophenol. The catalytic activity is found to be excellent and it can also be reused many times by simple filtration and activity remains maintained. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 2525–2532, 2010 相似文献
998.
Yan Kou Jin Yan Wang Xi Gao Jian 《中国化学快报》2007,18(5):598-600
A novel phthalazinone modified epoxy acrylate resin for the high temperature resistant ultravioet (UV) curable coating was synthesized. The methacrylated epoxy resins obtained were utilized to UV radiation curing by taking 2.5% (wt%) of photoinitiator in combination with 20% (wt%) of diluent, and generated the interpenetraring polymer networks. The cured film had good thermal and chemical stability. 相似文献
999.
Central composite experimental design methods have been used to examine the simultaneous effects of talc (Viaton Viatalc® 30), titanium dioxide (modified Rutile, Tioxide® TR92) and additional hindered phenolic stabiliser (Aquanox® L, a 50% w/w aqueous dispersion of Winstay® L) on the water uptake and UV stability of composite films based on a carboxylated styrene butadiene rubber (c-SBR) latex. The talc and TR92 were in situ treated as pre-dispersions with Solsperse® S27000 and Solplus® D540 dispersants, respectively. For water uptake related responses, quadratic models were found to provide the most accurate prediction of effects associated with interactions between talc and TR92. It was found that the addition of TR92 to formulations with high talc loading reduced the water uptake, this was attributed a packing effect that arose due to the vast difference in pigment and filler particle size. For responses related to photo-oxidation (Microscal unit/mercury lamp, carboxylic acid carbonyl growth was monitored by IR), linear models gave the best data fit, thus indicating negligible interaction between the three variables. Within the experimental space explored, the level of talc had by far the strongest influence; increasing talc level led to a proportional increase in rate of carbonyl growth. This corroborates previous single variable studies, where the iron impurities present in the talc were suspected to be associated with the pro-degradant effect observed. Interestingly, the addition of dispersants amplified the latter effect and strongly muted the UV stabilising effect of TR92. An optimised formulation based on c-SBR was determined from the response equations and subsequently evaluated; in general the actual response trends matched those predicted. The suitability of experimental design as a tool to discover effects, interactions and responses of the ingredients of a paint system, and to optimise its formulation was thus confirmed. 相似文献
1000.
P. K. Kamweru F. G. Ndiritu T. K. Kinyanjui Z. W. Muthui R. G. Ngumbu P. M. Odhiambo 《Journal of Macromolecular Science: Physics》2013,52(5):817-827
Plastic bags, mostly made of polyethylene, cause pollution as solid waste due to their nondegradable nature. Accelerated degradation, as a solution to mitigate the menace, can be achieved through moisture enhanced photolysis. This study evaluated the effect of three relative humidity environments, i.e., 25%, 40%, and 60% RH, at a constant temperature of 55°C. The effect was studied for ultraviolet (UV) irradiated and nonirradiated samples of polyethylene (PE) films processed under conventional ways. Photodegradation was initiated using ultraviolet irradiation in the ranges (200–300) nm and (300–400) nm for two hours and the effects of subsequent humidity treatment analyzed. Dynamic mechanical analysis was used to measure the dynamic storage modulus to monitor degradation. For nonirradiated samples, there was essentially no change in storage modulus at the three relative humidity environments after 550 hrs. Irradiation in the (300–400) nm range showed faster degradation than for the (200–300)nm range with the highest drop in storage modulus being 67% after 550 hrs. Raising the humidity from 25% to 40% and 60% RH resulted in 41%, 62%, and 67% drop of storage modulus, respectively, at the 550 hrs. 相似文献