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91.
92.
On the Synthesis of Sulfonated Derivatives of 2,3-Dimethylaniline and 3,4-Dimethylaniline Baking the hydrogensulfate salt of 2,3-dimethylaniline ( 1 ) or of 3,4-dimethylaniline ( 2 ) led to 4-amino-2,3-dimethylbenzenesulfonic acid ( 4 ) and 2-amino-4,5-dimethylbenzenesulfonic acid ( 5 ), respectively (Scheme 1). The sulfonic acid 5 was also obtained by treatment of 2 with sulfuric acid or by reaction of 2 with amidosulfuric acid. 3-Amino-4,5-dimethylbenzenesulfonic acid ( 3 ) and 5-Amino-2,3-dimethylbenzenesulfonic acid ( 6 ) were prepared by sulfonation of 1,2-dimethyl-3-nitrobenzene ( 9 ) to 3,4-dimethyl-5-nitrobenzenesulfonic acid ( 11 ) and of 1,2-dimethyl-4-nitrobenzene ( 10 ) to 2,3-dimethyl-5-nitrobenzenesulfonic acid ( 12 ), respectively, with subsequent Béchamp reduction (Scheme 1). Preparations of 2-amino-3,4-dimethylbenzenesulfonic acid ( 7 ) and of 6-amino-2,3-dimethylbenzenesulfonic acid ( 8 ) were achieved by the sulfur dioxide treatment of the diazonium chlorides derived from 3,4-dimethyl-2-nitroaniline ( 24 ) and from 2,3-dimethyl-6-nitroaniline ( 31 ) to 3,4-dimethyl-2-nitrobenzenesulfonyl chloride ( 29 ) and 2,3-dimethyl-6-nitrobenzenesulfonyl chloride ( 32 ), respectively, followed by hydrolysis to 3,4-dimethyl-2-nitrobenzenesulfonic acid ( 30 ) and 2,3-dimethyl-6-nitrobenzenesulfonic acid ( 33 ), and final reduction (Scheme 3). Compound 7 was also synthesized by reaction of 4-chloro-2,3-dimethylaniline ( 23 ) with amidosulfuric acid to 2-amino-5-chloro-3,4-dimethylbenzenesulfonic acid ( 20 ) and subsequent hydrogenolysis (Scheme 2). 4′-Bromo-2′, 3′-dimethyl-acetanilide ( 13 ) and 4′-chloro-2′, 3′-dimethyl-acetanilide ( 14 ) on treatment with oleum yielded 5-acetylamino-2-bromo-3,4-dimethylbenzenesulfonic acid ( 17 ) and 5-acetylamino-2-chloro-3,4-dimethylbenzenesulfonic acid ( 18 ), respectively. Their structures were proven by hydrolysis to 5-amino-2-bromo-3,4-dimethylbenzenesulfonic acid ( 21 ) and 5-amino-2-chloro-3,4-dimethylbenzenesulfonic acid ( 22 ), followed by reductive dehalogenation to 3 . 相似文献
93.
The synthesis of dimetallic olefin complexes of the type L1M1C7H7M2L2 (M1 = Fe, Co, Rh; M2 = Rh, Ir, Pd; L1 = CO, C5H5; L2 = diene, allyl, P(OR)3) is described. The fluxional structures were investigated by 13C-, 57Fe- and 103Rh-NMR.-spectroscopy, and a cisoid dimetallic coordination, including a (metal, metal)-bond, can be deduced for the C7H7-ring. 57Fe- and 103Rh-chemical shifts give indications for the charge distribution in the 34e-complexes. The homodimetallic complex (Cp)Rh(tropone)Rh(Cp) ( 13 , Cp = cyclopentadienyl) and the corresponding 2-methoxytropone complex 14 were synthesized in addition to the above mentioned complexes. A fluxional bis(1-3-η-allyl)-coordination of the two Rh-atoms was derived from the temperature-dependent 13C-NMR.-spectra. A spin simulation of the (Cp)-multiplets of 12 and 13 yields information about (Rh, Rh)-spin-coupling which amounts to ≈5 Hz at 30°. 相似文献
94.
Paul Von Ragué Schleyer José Walkimar De M. Carneiro 《Journal of computational chemistry》1992,13(8):997-1003
The closely related Cs ( 1 ) and C2v ( 3 ) structures of CH have been reinvestigated at many ab initio levels using MP2/6-31G** and MP2/6-311 + + G(2df, 2pd) geometries. The largest basis sets employed were 6-311G(3df, 2p), 6-311 + + G(3df, 3pd), and the Dunning “correlation consistent” polarized triple-split valence basis set (cc-pVTZ). Electron correlation was probed at the MP4 level, but the QCISD method was also used with the largest basis sets. While electron correlation favors 3 over 1 by about 2 kcal/mol, the correlated relative energies with all basis sets employed range from 0.36–1.03 kcal/mol in favor of 1 . The best estimate of this difference, 0.86 kcal/mol, is essentially identical with the (scaled) zero-point energy difference, 0.84 kcal/mol, favoring 3 over 1 . These results indicate that 1 and 3 have almost exactly the same energy at 0 K. Our best value for the dissociation energy of CH is 42.0 kcal/mol [QCISD(T)/6-311 + + G(3df, 3pd)//MP2(fu)/6-311 + + G(2df, 2pd), corrected to 298 K], which agrees very well with the experimental value. © 1992 by John Wiley & Sons, Inc. 相似文献
95.
应用原子吸收光谱法测定了内蒙古地产的笃斯茎、叶中的Cu,Fe,Zn,Mn,Ca,Mg等六种人体必需微量元素及宏量元素的含量。从而为评价笃斯的品质及其药理、药效提供了具有一定价值的数据。 相似文献
96.
运用毛细管电泳非接触式电导检测方法对4种中枢神经系统用药-盐酸阿扑吗啡、氢溴酸加兰他敏、富马酸喹硫平、氯氮平的分离进行了研究。考察了电泳介质的种类、浓度、分离电压、进样时间对分离效果的影响,在10 mmol/L三羟基氨基甲烷(Tris)-8 mmol/L柠檬酸(Cit)-20%甲醇的运行缓冲液中,激发电压为60V,激发频率为600kHz,4种药物在15 min内得到了分离。4种药物的线性范围分别为0.97~15.6 mg/L;0.97~15.6 mg/L;0.48~15.6 mg/L和0.97~250 mg/L,检测限为0.32,0.32,0.16和0.32 mg/L。 相似文献
97.
Abstract Geochemical and mineralogical investigations of plutonic rocks from the Meiβen massif indicate different magmatic evolution trends of the Freital sequence as well as for the central part of the complex Constant ε-NdT-345 values of ?1.5 of the Freital sequence and major/trace element data point to a fractional crystallization process. Based on ε-Nd values, 147Sm/144Nd ratios as well as on geochemical data affinities to alkali basalts cannot be excluded. Analogous conclusions have been drawn regarding mineral chemical data [10] and cathodoluminescence spectra of apatite [13]. Assimilation of old continental crust, reflected by relics of apatite and zircon, may be the reason that the ε-Nd values plot at the lower end of the “mantle array”. The pyroxene-monzodiorite from Gröba belongs to the same source environment as the Freital sequence (Nd-characteristics). The geological evolution of the central part of the studied plutonic complex is completely different to the Freital sequence: most of the intrusions show signatures of open system fractionation processes. The ε-NdT-345 value of ?1.46 of the Leuben monzonite indicates a narrow relation to the Freital sequence, whereas the ε-NdT-345 value of +2.27 of the Spitzgrund monzonite either reflects the derivation of another basic material then the Freital-type or the participation of other mixing component(s) from geologically young crust. Fabric and mineral chemical investigations of the porphyry-like granite GII point to a mixing process of basic xenocrysts, resembling the corresponding minerals of the Freital sequence, and granite melts [10]. Large amounts of old zircon cores [11] indicate the inheritance of continental crust components by the Hauptgranit. Isotopic investigations on various granitic samples (GII, Hauptgranit and Riesensteingranit) reflect an increasing trend towards the crustal source(s) of their parental melts. The ε-NdT-345 values are ?3.75, ?4.16 and ?6.13, respectively. Chemical parameters and the ε-NdT value of the Riesensteingranit agree with data of granites from the Saxonian Granulite Massif (see e.g. Wand et al. [8]; von Quadt, 1992). Thus, it may be possible that both granite types derived from similar sources. 相似文献
98.
Vidura D. Thalangamaarachchige Nadeesha J. Silva Daniel K. Unruh Adelia J.A. Aquino Clemens Krempner 《Tetrahedron》2019,75(13):1861-1864
The synthesis, structures and spectroscopic properties of M(MeOCH2CH2OMe2Si)3CBH3 (M-1-BH3) and M(MeOCH2CH2OMe2Si)3SiBH3 (M-2-BH3) (M?=?Li, Na, K) derived from reactions of BH3 with the alkali metal zwitterions [M(MeOCH2CH2OMe2Si)3C] (M-1) and [M(MeOCH2CH2OMe2Si)3Si] (M-2) (M?=?Li, Na, K), resp., are reported. X-ray analysis and DFT calculations reveal discrete zwitterionic structures with the octahedral alkali metal cations rigidly locked and charge separated from the BH3 units via pendant donors groups. Solution experiments with the hydride acceptors B(C6F5)3 and [Ph3C]2[B12C12] indicate that Na-1-BH3 can donate hydrides to form cations of formula [Na(MeOCH2CH2OMe2Si)3CBH2]+. 相似文献
99.
Miša Biro Darja Kavšek Jakub Karasiński Piotr Szwarczewski Ewa Bulska Darinka Brodnjak Vončina 《Central European Journal of Chemistry》2014,12(6):687-699
The development and validation of a reliable analytical procedure for the determination of selected metals (Cd, Cr, Cu, Pb, Zn and Mn) in sediments accumulated in the Utrata River (Poland) is described. The aqua regia extraction followed by inductively coupled plasma optical emission spectrometry (ICP-OES) was used for this purpose. The optimized analytical procedure was validated, and adequate quality control actions were implemented in order to provide reliable data. The precision under’ within-laboratory’ reproducibility conditions was estimated from duplicate analysis. Certified reference material (CRM) was used in order to evaluate the accuracy of the results regarding the sewage sludge amended soil CRM 143R. The detection limits for all elements of interest were well-below their content in the investigated sediment samples. The obtained reliable data could be used for assessment of the relationship between human economic activity in the past and the geochemical features of the sediments. 相似文献
100.
Maja Vončina Robert Tisu Jožef Medved 《Journal of Thermal Analysis and Calorimetry》2017,129(1):117-122
Since titanium metal first became a commercial reality in 1950, corrosion resistance has been an important consideration in its selection as an engineering structural material. Titanium has gained acceptance in many media where its corrosion resistance and engineering properties have provided the corrosion and design engineer with a reliable and economic material. Titanium, like any other metal, is subject to corrosion in environments of air, oxygen, moisture, and so on. In this work, high-temperature stability of Ti and various Ti-alloys (by ASTM standard) was investigated. The best results showed that for Ti-Gr.5 alloy, the oxidation at 800 °C was 3.39% and at 900 °C 8.35%. For the comparison, commercial pure Ti-alloys Ti-Gr.2 and Ti-Gr.37 containing Al were used, whereas the oxidation resistance was much worse. 相似文献