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101.
V. V. Nedel'ko B. L. Korsounskii T. S. Larikova V. R. Stepanov N. V. Chukanov I. V. Nedel'ko 《Russian Chemical Bulletin》1994,43(11):1812-1815
The thermal decomposition of 1-ethyl-5-iodotetrazole in a melt and in solutions was studied using thermogravimetry, manometry, pyrolytic mass spectrometry, and IR spectroscopy. The kinetic and activation parameters of the process and the nature of the decomposition products were determined. The reaction mechanism is assumed to involve equilibrium tautomeric rearrangement of the tetrazole to azidoazomethine form followed by homolytic cleavage of the C-I bond.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 1923–1926, November, 1994.The authors are grateful to O. A. Ivashkevich and P. N. Gaponic (Belarussian State University), who provided the samples of the tetrazole. 相似文献
102.
丙烯选择氧化铋钼铁复氧化物催化剂组成,结构及性能的研究 总被引:1,自引:0,他引:1
采用XRD、Raman、XPS及催化剂性能评价等手段,考察了Bi_3(FeO_4)(MoO_4)_2和Fe_2(MoO_4)_3分别存在及两者共存时对Bi-Mo复氧化物体系催化性能的影响.结果表明,这两种含Fe物种的存在都有助于改善Bi-Mo系复氧化物催化剂对丙烯选择氧化反应的催化性能.但两者在作用机理上有所不同.Fe_2(MoO_4)_3本身无催化活性,但在反应条件下可部分还原为FeMoO_4形成Fe~(3+)/Fe~(2+)氧化还原对;且其地结构上与α-Bi_2(MoO_4)_3相匹配,这些因素都有助于促进催化体系中电子和氧物种的传递及催化剂表面活性中心的再生,从而提高催化性能.Bi_3(FeO_4)(MoO_4)_2在反应条件下也可形成Fe~(3+)/Fe~(2+)氧化还原对,但由于其Fe~(3-)所处的化学环境与Fe_2(MoO_4)_3很不相同,且Fe的含量也不及Fe_2(MoO_4)_3,因此它在促进催化体系中电子和氧物种的传递及催化剂表面活性中心的再生等方面的性能较差,但它对提高催化剂表面的活性中心(Bi-Mo对)数目有贡献. 相似文献
103.
SynthesesandCharacterizationsof(η~5-C_5H_5)MoFeCo(CO)_8(μ_3-S)and(η~5-C_5H_5)_2Mo_2Fe(CO)_7(μ_3-S):X-rayCrystalStructureof(η~5-C_5H_... 相似文献
104.
105.
A polyacrylate/polyurethane (P(A) / P(U)) composite coating has been prepared bycrosslinking an acetoacetylated polyacrylate with a vinylic group terminated polyurethaneat room temperature. A model Michael reaction between ethyl acetoacetate (EAA) andmethyl acrylate (MA) was designed to study the crosslinking mechanism. It was foundthat the two active hydrogen atoms in acetoacetyl group can both add to vinylic groupsand the yield of mono- and bis-adducts are much affected by the molar ratio of acetoacetylto vinylic groups. Higher crosslinking degree and better properties could be obtained withdecreasing the molar ratio of the two active groups from 1/1 to 0.6/1 in the compositecoatings. 相似文献
106.
107.
A Kinetic Evidence for the Nitroxyl Radicals Recycling Mechanism in the Photostabilizing Process of HALS 总被引:1,自引:0,他引:1
XiaoXuanLIU XingHongZHANG GuangGuoWU JianWenYANG ZhaoHuaZENG YongLieCHEN 《中国化学快报》2003,14(10):1085-1088
The photoinduced bulk polymerization of a reactive-hindered amine fight stabilizers(r-HALS), 4-acryloyl-2, 2, 6, 6-tetramethylpiperidinyl (ATMP), was performed at 80℃ by using a DPC technique. An unique periodic exponential attenuation-type oscillating curve was found when the polymerization was carried out in air, but this phenomenon was not found in nitrogen.It is supposed that this unique kinetic performance may be attributed to nitroxyl radicals that are produced in situ from the oxidation of ATMP. ATMP polymer with narrow polydispersity (d =1.03) can be obtained by photoinduced solution polymerization of ATMP. The signal detected in ESR may be assigned to the nitroxyl radicals in the matrix of ATMP polymer. Since this kind of recycling of nitroxyl radicals is well documented for the photostabilizing mechanism of HALS, the present results may serve as a kinetic evidence for this mechanism. 相似文献
108.
PTC特性的复合导电体系中炭粒子分布的逾渗模型与电阻率的计算 总被引:17,自引:0,他引:17
综述了炭黑填充型导电高分子复合体系的几种导电理论;讨论了导电载流子分布的各种假说及模型;比较了不同模型的理论预测与实验结果的差异性。 相似文献
109.
本文通过对锌(Ⅱ)—硫氰酸盐—孔雀绿体系溶剂浮选过程的考察,提出了待测Zn~(2+)离子从水相被输送到有机相,可以用吸附机理和粘附机理来解释;同时还对影响锌溶剂浮选的主要因素:溶液的pH,气泡的大小和气体流速等进行了讨论。 相似文献
110.
Martín-Matute B Bogár K Edin M Kaynak FB Bäckvall JE 《Chemistry (Weinheim an der Bergstrasse, Germany)》2005,11(20):5832-5842
A range of ruthenium cyclopentadienyl (Cp) complexes have been prepared and used for isomerization of allylic alcohols to the corresponding saturated carbonyl compounds. Complexes bearing CO ligands show higher activity than those with PPh3 ligands. The isomerization rate is highly affected by the substituents on the Cp ring. Tetra(phenyl)methyl-substituted catalysts rapidly isomerize allylic alcohols under very mild reaction conditions (ambient temperature) with short reaction times. Substituted allylic alcohols have been isomerized by employing Ru-Cp complexes. A study of the isomerization catalyzed by [Ru(Ph5Cp)(CO)2H] (14) indicates that the isomerization catalyzed by ruthenium hydrides partly follows a different mechanism than that of ruthenium halides activated by KOtBu. Furthermore, the lack of ketone exchange when the isomerization was performed in the presence of an unsaturated ketone (1 equiv), different from that obtained by dehydrogenation of the starting allylic alcohol, supports a mechanism in which the isomerization takes place within the coordination sphere of the ruthenium catalyst. 相似文献