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991.
5-(4-丙氨酸丁氧苯基)-10,15,20-三苯基卟啉及其配合物的合成和性质 总被引:1,自引:0,他引:1
本文首次合成了一种新型的单取代的丙氨酸四苯基卟啉,5-(4-丙氨酸丁氧苯基)-10,15,20-三苯基卟啉(H2L),及其Co(Ⅱ)、Cu(Ⅱ)、Zn(Ⅱ)配合物(CoL、CuL、ZnL),用元素分析、电子光谱、红外光谱、荧光光谱和激光拉曼光谱进行表征。研究了ML存在下,用氧气氧化芳醛的过程,测定了反应体系的吸氧动力学曲线,研究了氧化过程金属卟啉可见光谱变化以及底物和金属卟啉浓度对反应的影响。结果表明,CoL能加速芳醛氧化反应,最大吸氧速率随CoL浓度的增加而增大,但反应诱导期随CoL浓度增大而延长。 相似文献
992.
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995.
MacrocyclicarsinousacidestersareusuallypreparedbycondensationofdichloroalkylarsinesRAsCI,Iwithdidsinthepresenceoforganicalkali].ThemethoddescribedhereinvolvesthetransformationofintermediatefromItohis(dimethylamino)alkylarsineRAs(NMe,),2andthereactionof2withdidsindryTHFtoleadtotheformationoftitlecompounds.2canreactsmoothlywithdidsintheabsenceoforganicalkalitogeneratecorrespondingmacrocyclicarsinousacidesters4anddimethylaminewhichescapesfromthereactingsystemasagasinreflux.Althoughonemoreste… 相似文献
996.
神经红蛋白突变体(F28Y,F106Y)的构建、 表达与表征 总被引:2,自引:0,他引:2
构建了神经红蛋白F28Y, F106Y的两种突变体, 并进行了表达、 纯化和谱学表征. 电喷雾质谱表明突变体蛋白的分子量与理论值一致. 氧化型和还原型F28Y及F106Y的紫外 可见吸收光谱与野生型相似, 仅氧化型F28Y的Soret 带有2 nm的蓝移, 说明这两种突变体蛋白仍保持六配位形式. F28Y的荧光最大发射峰明显红移(340 nm→347 nm), 表明其荧光基团更加暴露于极性环境中. 圆二色光谱表明, 突变体蛋白的α 螺旋含量降低且F28Y产生了β 折叠, 这是由于F28相对于F106则位于疏水腔外部且更加接近于溶剂表面所致. 热稳定性顺序为NGB>F28Y>F106Y, F106Y最不稳定, 是因为其与血红素间存在着较强的疏水作用, 突变使F106与血红素间的作用力减弱, 从而导致血红素在热变性条件下更容易从蛋白中解离出来. 相似文献
997.
Fully or partially substituted 1-iodo- or 1-bromo-1,3-dienes could be readily lithiated using t-BuLi or n-BuLi to afford their corresponding 1-lithio-1,3-diene derivatives in quantitative yields. When these in situ generated lithium reagents were treated with organonitriles, depending on the substitution patterns of the butadienyl skeletons, substituted pyridines, pyrroles, and/or linear butadienyl imines were formed in good to excellent yields via N-lithioketimine intermediates. In the cases of 1,2,3,4-tetrasubstituted and 2,3-disubstituted 1-lithio-1,3-dienes, pyridine derivatives or linear butadienyl imines were generally formed depending on the reaction temperatures. When 1,2,3,4-tetrasubstituted 4-halo-1-lithio-1,3-dienes and 1,2-disubstituted 1-lithio-1,3-dienes were treated with organonitriles, pyrrole derivatives or linear butadienyl imines were obtained. Competition between 5-exo and 6-endo cyclization was found to be responsible for the formation of either pyrroles or pyridines. Selective elimination of RLi from the lithiated cyclic N-containing intermediates was observed. The order of elimination was found to be LiCl > Me3SiLi > LiH. 相似文献
998.
Four new triterpenoid saponins, named scheffarboside A – D ( 1 – 4 ), along with five known saponins were isolated from the stems of Schefflera arboricola. The structures of the four new saponins were determined as 3‐O‐(O‐β‐glucuronopyranosyl‐(1 → 3)‐O‐α‐rhamnopyranosyl‐(1 → 2)‐α‐arabinopyranosyl)oleanolic acid ( 1 ), 3‐O‐(O‐α‐arabinopyranosyl‐(1 → 4)‐O‐α‐arabinopyranosyl‐(1 → 3)‐O‐α‐rhamnopyranosyl‐(1 → 2)‐α‐arabinopyranosyl)oleanolic acid ( 2 ), 3‐O‐(O‐α‐arabinopyranosyl‐(1 → 4)‐O‐α‐arabinopyranosyl‐(1 → 3)‐O‐α‐rhamnopyranosyl‐(1 → 2)‐α‐arabinopyranosyl)hederagenin ( 3 ), 3‐O‐(O‐α‐arabinopyranosyl‐(1 → 4)‐O‐α‐arabinopyranosyl‐(1 → 3)‐O‐α‐rhamnopyranosyl‐(1 → 2)‐α‐arabinopyranosyl)oleanolic acid O‐α‐rhamnopyranosyl‐(1 → 4)‐O‐β‐glucopyranosyl‐(1 → 6)‐β‐glucopyranosylester ( 4 ), respectively, on the basis of spectroscopic and chemical degradation methods. 相似文献
999.
A facile one-step method has been developed for the synthesis of N-protected α-amino aldehyde acetals in moderate to good yields by three-component reaction of fluoroalkanesulfonyl azides, vinyl ethers and alcohol at 0 °C within 10 min. This practical synthetic method provides a convenient and expeditious access to N-per(poly)fluoroalkanesulfonyl α-amino aldehyde acetals. 相似文献
1000.
The first one-dimensional (1-D) indiumphosphate chain, In2(HPO4)2(H2PO4)2F2·C4N2H12 (1), has been hydrothermally prepared using piperazine (PIP) as a template. The structure consists of infinite chains of trans,trans-corners-sharing InO4F2 octahedra with the adjacent octahedra being bridged by tetrahedral PO3(OH) and PO2(OH)2 units, which are H-bonded with amine groups of the organic cations. Interestingly, this macroanionic chain InP2O8H3F− is similar to that found in the mineral tancoite-like chains and has potential to further set up higher-dimensional networks. On heating 1 in the presence of additional phosphoric acid at 180 °C under hydrothermal condition, compound 2, In2(OH)(H2O)(PO4)2·H3O·H2O, possessed a 3-D structure building from the repetition of a secondary building unit is obtained. When 1 is heated with additional PIP, an unknown phase, compound 3 is formed. Finally, on treatment with another amine, such as diethylenetriamine or 1,4-diaminobutane, at 180 °C, 1, as a precursor, can convert into a previously known 3-D framework structure with 16-membered ring compound 4. Compounds 1 and 2 are determined by single-crystal X-ray diffraction. Furthermore, 1 is characterized by X-ray powder diffraction, IR spectroscopy, inductively coupled plasma analysis, thermogravimetric analysis and differential thermal analysis. 相似文献