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871.
The recent promising applications of deuterium-labeled pharmaceutical compounds have led to an urgent need for the efficient synthetic methodologies that site-specifically incorporate a deuterium atom into bioactive molecules. Nevertheless, precisely building a deuterium-containing stereogenic center, which meets the requirement for optimizing the absorption, distribution, metabolism, excretion and toxicity (ADMET) properties of chiral drug candidates, remains a significant challenge in organic synthesis. Herein, a catalytic asymmetric strategy combining H/D exchange (H/D-Ex) and azomethine ylide-involved 1,3-dipolar cycloaddition (1,3-DC) was developed for the construction of biologically important enantioenriched α-deuterated pyrrolidine derivatives in good yields with excellent stereoselectivities and uniformly high levels of deuterium incorporation. Directly converting glycine-derived aldimine esters into the deuterated counterparts with D2O via Cu(i)-catalyzed H/D-Ex, and the subsequent thermodynamically/kinetically favored cleavage of the α-C–H bond rather than the α-C–D bond to generate the key N-metallated α-deuterated azomethine ylide species for the ensuing 1,3-DC are crucial to the success of α-deuterated chiral pyrrolidine synthesis. The current protocol exhibits remarkable features, such as readily available substrates, inexpensive and safe deuterium source, mild reaction conditions, and easy manipulation. Notably, the synthetic utility of a reversed 1,3-DC/[H/D-Ex] protocol has been demonstrated by catalytic asymmetric synthesis of deuterium-labelled MDM2 antagonist idasanutlin (RG7388) with high deuterium incorporation.A strategy of combining H/D-Ex and azomethine ylide-involved 1,3-DC was developed for the construction of α-deuterated pyrrolidine derivatives in good yields with excellent stereoselectivities and uniformly high levels of deuterium incorporation. 相似文献
872.
新型药物辅料2-羟丙基-β-环糊精的色谱分离纯化 总被引:1,自引:2,他引:1
利用薄层色谱方法对碱浓度为1.5%、β-环糊精∶环氧丙烷(摩尔比)=1∶21的条件下生成的2-羟丙基-β-环糊精进行了定性分析,并通过对展开剂的选择和优化,得到了3种能有效分离不同取代度2-羟丙基-β-环糊精的展开剂体系,分别为正丙醇-水-浓氨水(6∶3∶1,V/V),异丙醇-水-浓氨水(6∶4∶0.5,V/V)和乙醇-水-浓氨水(6∶3∶0.8,V/V)。通过以乙醇体系为洗脱剂的硅胶柱色谱对其进行分离纯化,得到了两种不同取代的2-羟丙基-β-环糊精。经过ESI-MS谱图分析,确定分离后产品分别为单取代和双取代2-羟丙基-β-环糊精。 相似文献
873.
以苯、吡啶、尼古丁和普鲁卡因为探测因子,考察了酰胺型、胺型、醚型和酯型4种"包埋"极性官能团的新型键合固定相对碱性化合物在流动相pH值分别为3.0和7.0时的热力学焓变.实验结果表明,新型固定相由于烷基分子链中"嵌入"极性官能团,因此在流动相pH为3.0时温度对碱性溶质的保留影响相互差异较大.在流动相pH为7.0时,根据Van′t Hoff方程计算出4种待测物质从流动相转移到固定相上的ΔH0,从ΔH0的绝对值大小、相关系数以及实际的分离效果可以发现,在分离强碱性物质时,若实验条件一样,则分离效果是酰胺型和胺型>酯型固定相>醚型固定相,但它们均优于传统的固定相. 相似文献
874.
[reaction: see text] A novel thiourea-based C2-symmetric ligand was synthesized, and its application in the palladium-catalyzed Heck and Suzuki coupling reactions of arenediazonium salts was evaluated. The reactions, which were performed at room temperature, without added base, and under aerobic conditions, produced product in 4 h with good yield. The corresponding arenediazonium salts were easily generated in one step from anilines. 相似文献
875.
Copper(I)-catalyzed 1,3-dipolar cycloaddition reaction of nonfluorescent 3-azidocoumarins and terminal alkynes afforded intense fluorescent 1,2,3-triazole products. The mild condition of this reaction allowed us to construct a large library of pure fluorescent coumarin dyes. Since both azide and alkyne are quite inert to biological systems, this reaction has potential in bioconjugation and bioimaging applications. [reaction: see text] 相似文献
876.
877.
Polylactide-based polyurethane and its shape-memory behavior 总被引:3,自引:0,他引:3
A series of polylactide polyurethanes (PLAUs) were synthesized from poly(l-lactide) diols, hexamethylene diisocyanate (HDI), and 1,4-butanediol (BDO). Their thermal and mechanical properties and shape-memory behavior were studied by infrared spectroscopy (IR), differential scanning calorimetry (DSC), wide angle X-ray diffraction (WAXD), tensile testing, and thermal mechanical analysis (TMA). The Tgs of these polymers were in the range of 33-53 °C, and influenced by the Mn of the PLA diol and the ratio of the soft-segment to the hard-segment. These materials can restore their shapes almost completely after 150% elongation or twofold compression. By changing the Mn of the PLA diol and the ratio of the hard-to-soft-segment, their Tgs and shape-recovery temperatures can be adjusted to the neighborhood of the body temperature. Therefore, these PLAUs are expected to find practical medical applications. 相似文献
878.
Juan Li Xihe Yu Hongfang Wang Kun Xu Xinyu Wu Lei Hou Jing Li 《Transition Metal Chemistry》2006,31(6):770-775
A new chainlike polymer, Na[Ce(dipic)(H2O)3]2 [CrMo6H6O24] · 13H2O (H2dipic = pyridine-2,6-dicarboxylic acid) (1), has been synthesized and characterized by elemental analysis; IR and XPS spectroscopy, TG analysis, and single-crystal X-ray
diffraction. Compound (1) is built up of Anderon-type polyoxoanions as structural motifs and cerium–dipic coordination fragments as linkers to yield
an unprecedented one-dimensional chain. Such chains are further in close contact forming a three-dimensional supramolecular
framework with channels via extensive hydrogen-bonding interactions among polyoxoanions, dipic ligands and water molecules. Furthermore, the magnetic
properties of compound (1) have been studied by measuring their magnetic susceptibility in the temperature range 2–300 K. 相似文献
879.
Synthesis of the titanium silicalite TS-1 was first reported by Taramasso et al[1]in 1983. TS-1 has received considerable interest during the last decade because of its unique catalytic properties in oxidation reactions involving H2O2 as the oxidant. It is accepted that the extraframework Ti species in TS-1 favor the decomposition of H2O2and should be avoided. But in the present study, it was observed that there was a kind of Ti species inactive in both the oxidation reaction and the decomposition of H2O2. 相似文献
880.