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21.
淫羊藿根与叶活性成分的分析和比较 总被引:8,自引:0,他引:8
采用细胞膜色谱法(CMC)筛选,并结合离体药理实验确定主要活性成分,利用高效液相色谱法分析比较了淫羊藿根与叶中的活性成分及其差异性.色谱条件为Kromasil ODS 柱(150 mm× 4.6 mm.I.D )流动相甲醇-水(70:30,V:V);检测波长270nm。筛选发现淫羊藿根中的两个有效成分YYH-214和YYH-216对血管有较强的舒张作用,表明活性成分在CMC模型体系中的保留特性与药理作用之间存在良好的相关性。在此色谱条件下淫羊藿叶未检测到这两种活性成分. 相似文献
22.
Rie Namme 《Tetrahedron letters》2005,46(17):3033-3036
Acid-promoted α-stereoselective O-glycosidation of 1-exo-methylenesugars was successfully applied to the synthesis of a PI-88 analogue. By using methanesulfonic acid as a promoter, 1′-C-methyl-α-disaccharides with p-methoxybenzyl protection were obtained in high yield. The sequence of selective deprotection and glycosidation provided 1-C-methyl-pentasaccharide efficiently. 相似文献
23.
A rapid microtiter plate assay for the detection of inhibitors of the Na+, K+-ATPase has been developed. The assay is based on the measurement of inorganic phosphate released from the substrate, ATP,
and has been designed to be carried out in the individual wells of a microtiter plate. Since the production of inorganic phosphate
is determined colorimetrically, multiple samples can be tested simultaneously using a microtiter plate reader. This microtiter
plate assay is particularly useful for screening large numbers of samples, such as microbial culture supernatants. 相似文献
24.
Chandra S Gupta LK 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2005,62(4-5):1089-1094
Nickel(II) complexes, having the general composition Ni(L)2X2, have been synthesized [where L: isopropyl methyl ketone semicarbazone (LLA), isopropyl methyl ketone thiosemicarbazone (LLB), 4-aminoacetophenone semicarbazone (LLC) and 4-aminoacetophenone thiosemicarbazone (LLD) and X=Cl-, 1/2SO(4)2-]. All the Ni(II) complexes reported here have been characterized by elemental analyses, magnetic moments, IR, electronic and mass spectral studies. All the complexes were found to have magnetic moments corresponding to two unpaired electrons. The possible geometries of the complexes were assigned on the basis of electronic and infrared spectral studies. Newly synthesized ligand and its nickel(II) complexes have been screened against different bacterial and fungal growth. 相似文献
25.
Efficient routes to hitherto unknown 1d-2,5-di-azido-di-deoxy-allo-inositol, 1d-2,5-di-amino-di-deoxy-allo-inositol, 1l-1-azido-1-deoxy-chiro-inositol and 1l-1-amino-1-deoxy-chiro-inositol were developed by using cheaply available myo-inositol as the starting material. Preliminary investigations on the enzyme inhibitory properties were done. The methodology reported is amenable to gram scale synthesis and thus can find application in natural product synthesis. 相似文献
26.
Atsushi Yamazoe 《Tetrahedron letters》2004,45(45):8359-8362
Indole 3-acetic acid, a plant hormone auxin, regulates every aspects of plant growth and development. In the screening for specific inhibitors on auxin signaling using the transgenic Arabidopsis plant harboring the auxin-responsive reporter gene, terfestain A was found to be a novel inhibitor of auxin signaling from the culture of Streptomyces sp. F40. The structure of terfestatin A was determined to be p-terphenyl β-glucoside on the basis of spectroscopic analyses, chemical degradation, and total synthesis. 相似文献
27.
Toshiaki Sunazuka Masaki Handa Tatsuya Shirahata Kazuhiko Otoguro Satoshi ōmura 《Tetrahedron》2004,60(36):7845-7859
In the current studies, we used the Kakisawa-Kashman modification of the Mosher NMR method to determine the complete absolute stereochemistry of arisugacins. We also report the convergent total synthesis of (+)-arisugacins A and B by a sequence including (i) ruthenium complex-catalyzed asymmetric reduction of the cyclohexenone derivative; (ii) stereoselective construction of the arisugacin skeleton by a Knoevenagel-type reaction of an α,β-unsaturated aldehyde derivative with production of a 4-hydroxy-2-pyrone derivative as a key reaction; and (iii) stereoselective dihydroxylation to give the diol derivative, followed by deoxygenation. Accordingly, we defined the absolute structures of arisugacins A and B as 4a-(R),6a-(R),12a-(R), and 12b-(S). Finally, we characterized the bioactivities of the synthetic intermediates to understand the structure-activity relationships of the arisugacins. 相似文献
28.
Xiaoping YangChristopher R. Lowe 《Tetrahedron letters》2003,44(7):1359-1362
In this report, the stepwise synthesis of a novel rigid and functionalised macrocycle 2 based on triazine and phenylenediamine linkers, is presented. Poor recognition of the macrocycle 2 for its substrates is observed, which shows experimentally that for the meltriazine based-calix[6]arene system, the binding ability of the melamine moiety gets more benefit from the ring flexibility derived from a xylenediamine linker 1 than from a phenylenediamine linker 2. 相似文献
29.
The reaction of 2,5-diamino-4-benzylamino-pyrimidin-6(III)-one (6) with benzoyl isothiocyanate furnished 2-amino-4-benzylamino-5-[1-(3-benzoylthioureido)]-pyrimidin-6(1H)-one (7) in good yield. The title compound I was synthesized from compound 7 via a cyclodesulfurative reaction with DCC in DMF at 80°C directly to form 8-benzoylamino-9-benzylguanine (9) which was subsequently treated with 1 N sodium hydroxide. 相似文献
30.
以 5 甲氧基 (或氯 ) 2 巯基苯并咪唑 ( 1)为原料 ,经缩合和还原得到 5 甲氧基 (或氯 ) 2 ( 4 氨基苯硫基 )苯并咪唑 ( 3 ) ,再与异硫氰酸烃基酯反应得到取代硫脲 4,最后与卤代烃反应得到 12个新的S 烃基 1 烃基 3 [4 ( 5 甲氧基 (或氯 )苯并咪唑 2 巯基 )苯基 ]异硫脲化合物 5 .其结构经IR ,1 HNMR ,MS及元素分析确证 .初步的药理试验表明 ,12个目标化合物的iNOS抑制活性均强于阳性对照药氨基胍 相似文献