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91.
Preparation of chiral gamma-substituted-gamma-lactones (1) through kinetic resolution is described. (S)-(-)-1-Phenylethylamine (2) in the presence of anhydrous AlCl(3) shows satisfactory levels of enantioselection in reaction with racemic gamma-substituted-gamma-lactones 1, where (R)-1 remains unreacted, while (S)-1 is enantioselectively converted to the ring-opened amide (S,S)-4. The enantiopurity of (R)-(+)- gamma-substituted gamma-lactones recovered ranges from 62-98% ee. 相似文献
92.
The purpose of this study was to formulate a gelled self-emulsifying drug delivery system (SEDDS) containing ketoprofen as
an intermediate in the development of sustained release solid dosage form. Captex 200 (an oil), Tween 80 (a surfactant), and
Capmul MCM (a cosurfactant) were used to formulate SEDDS. Silicon dioxide was used as a gelling agent, which may aid in solidification
and retardation of drug release. Effect of concentrations of cosurfactant and gelling agent on emulsification process and
in vitro drug diffusion was studied using 32 factorial design. Multiple regression analysis data and response surfaces obtained showed that liquid crystal phase viscosity
increased significantly with increasing amount of silicon dioxide, which in turn caused an increase in average droplet size
of resultant emulsion and slower drug diffusion. Drug release from the formulation increased with increasing amount of cosurfactant. 相似文献
93.
Conclusion Hydrolyzed gelatins (Byco-A, Byco-O and Byco-C), when used as binders, yielded soft, uniform granules with good flow properties.
As the molecular weight and viscosity of hydrolyzed gelatins increased, the compressibility of granules decreased and their
compactability increased. The balance between compressibility and compactability of granules may be achieved by careful monitoring
of the molecular weight of hydrolyzed gelatins that can serve as potential binders. 相似文献
94.
95.
Hrishikesh Pandit Sandhya Gopal Archana Sonawani Ajit Kumar Yadav Asif S. Qaseem Himangi Warke Anushree Patil Rahul Gajbhiye Vijay Kulkarni Maha Ahmed Al-Mozaini Susan Idicula-Thomas Uday Kishore Taruna Madan 《PloS one》2014,9(7)
Surfactant Protein SP-D, a member of the collectin family, is a pattern recognition protein, secreted by mucosal epithelial cells and has an important role in innate immunity against various pathogens. In this study, we confirm that native human SP-D and a recombinant fragment of human SP-D (rhSP-D) bind to gp120 of HIV-1 and significantly inhibit viral replication in vitro in a calcium and dose-dependent manner. We show, for the first time, that SP-D and rhSP-D act as potent inhibitors of HIV-1 entry in to target cells and block the interaction between CD4 and gp120 in a dose-dependent manner. The rhSP-D-mediated inhibition of viral replication was examined using three clinical isolates of HIV-1 and three target cells: Jurkat T cells, U937 monocytic cells and PBMCs. HIV-1 induced cytokine storm in the three target cells was significantly suppressed by rhSP-D. Phosphorylation of key kinases p38, Erk1/2 and AKT, which contribute to HIV-1 induced immune activation, was significantly reduced in vitro in the presence of rhSP-D. Notably, anti-HIV-1 activity of rhSP-D was retained in the presence of biological fluids such as cervico-vaginal lavage and seminal plasma. Our study illustrates the multi-faceted role of human SP-D against HIV-1 and potential of rhSP-D for immunotherapy to inhibit viral entry and immune activation in acute HIV infection. 相似文献
96.
Protein-RNA interactions are essential for many biological processes. However, the structural mechanisms underlying these interactions are not fully understood. Here, we analyzed the protein surface shape (dented, intermediate or protruded) and the RNA base pairing properties (paired or unpaired nucleotides) at the interfaces of 91 protein-RNA complexes derived from the Protein Data Bank. Dented protein surfaces prefer unpaired nucleotides to paired ones at the interface, and hydrogen bonds frequently occur between the protein backbone and RNA bases. In contrast, protruded protein surfaces do not show such a preference, rather, electrostatic interactions initiate the formation of hydrogen bonds between positively charged amino acids and RNA phosphate groups. Interestingly, in many protein-RNA complexes that interact via an RNA loop, an aspartic acid is favored at the interface. Moreover, in most of these complexes, nucleotide bases in the RNA loop are flipped out and form hydrogen bonds with the protein, which suggests that aspartic acid is important for RNA loop recognition through a base-flipping process. This study provides fundamental insights into the role of the shape of the protein surface and RNA secondary structures in mediating protein-RNA interactions. 相似文献
97.
98.
Summary Root exudate from seedlings ofCicer arietinum L. was collected in a chamber under aseptic conditions. The exudate was fractionated into anion, cation and neutral fractions.
The anionic fraction was made up of galacturonic acid, gluconic acid, mannuronic acid and two unidentified compounds withR
f
values 0.56 and 0.62. The cationic fraction contained alanine, arginine, aspartic acid, cystine, glycine, histidine, isoleucine,
leucine, lysine and serine. The neutral fraction was made up of arabinose, galactose, glucose, ribose and xylose. The amino
acids contributed to the bulk of the root exudate. The ratio of anionic, cationic and neutral fraction was 1∶7∶2. The crude
root exudate was tested for its chemotactic ability using the capillary tube method. It was highly chemotactic for theRhizobium sp. The individual fractions and their various combinations were tested for chemotaxis. The chemotactic response of the Cicer
strain of Rhizobium was least with anionic fraction most with cationic fraction and intermediate with neutral fraction. Maximum
chemotactic response among the fractional combinations was obtained with all the three fractions and least with cationic plus
neutral factions. Individual compounds constituting the various fractions were also tried for their ability to elicit chemotactic
response. The organism exhibited maximum positive chemotactic response to histidine and negative response to alanine among
the amino acids and to glucose and gluconic acid among the sugars and sugar acids. 相似文献
99.
100.
Simultaneous extraction of bioactive limonoid aglycones and glucoside from Citrus aurantium L. using hydrotropy 总被引:1,自引:0,他引:1
Dandekar DV Jayaprakasha GK Patil BS 《Zeitschrift für Naturforschung. C, Journal of biosciences》2008,63(3-4):176-180
Citrus limonoids were demonstrated to possess potential biological activities in reducing the risk of certain diseases. Limonoids are present in citrus fruits in the form of aglycones and glucosides. At present, limonoid aglycones and limonoid glucosides are extracted in multiple steps using different solvents. In order to understand their potential bioactivity, it may be beneficial to isolate and purify these compounds using environment friendly methods. A new method of extraction and purification of limonoids was established using a hydrotrope polystyrene adsorbent resin. Extraction of aglycones and glucosides was achieved in a single step, using an aqueous solution of sodium cumene sulphonate (Na-CuS). Sour orange (Citrus aurantium L.) seed powder was extracted with 2 M Na-CuS solution at 45 degrees C for 6 h. The filtered extract was diluted with water and loaded on an SP 700 adsorbent column. The column was washed with distilled water to remove the hydrotrope and then eluted using water and methanol in different compositions to obtain three compounds. The structures of the isolated compounds were confirmed by NMR spectroscopy as deacetyl nomilinic acid glucoside (DNAG), deacetyl nomilin (DAN) and limonin (LIM). 相似文献