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961.
Yoshikazu Takagi Takane Fujimori Tsuyoshi Hata Hajime Kaneko Kunio Kato 《Bioscience, biotechnology, and biochemistry》2013,77(3):705-706
Glutamine production was investigated by coupling of glutamine synthetase from Gluconobacter suboxydans with a sugar fermentation system of baker's yeast (energy generating system). Under the optimum condition, 22 mM glutamine was formed in 3 hr, and the yield was 92% based on the substrate glutamate. The first step of the process was the accumulation of fructose 1,6-diphosphate (FDP) as a reservoir of fermentation energy, in the presence of a high concentration of inorganic phosphate; and the second step was accomplished by coupling the degradation of FDP with glutamine synthetase reaction through an ADP-ATP system. The effects of enzyme concentration, additives in the reaction mixture and others on glutamine formation were investigated, and the importance of three factors was pointed out: (a) the ratio of activity of energy generating system to utilizing system, (b) contaminated enzyme(s) in the energy utilizing system and (c) the enzymatic properties of the energy utilizing system. 相似文献
962.
Tsuyoshi Nishitoba Hiroji Sato Takanori Kasai Hirokazu Kawagishi Sadao Sakamura 《Bioscience, biotechnology, and biochemistry》2013,77(6):1793-1798
Four new bitter terpenoids, lucidenic acids A (1), B (2), C (3) and ganoderic acid C (5), were isolated from the fruiting bodies of Ganoderma lucidum, together with the known bitter ganoderic acid B (4). On the basis of spectroscopic data and chemical conversion, their structures were determined to be 7β-hydroxy-4,4,14α-trimethyl-3,11,15-trioxo-5α-chol-8-en-24-oic acid, 7β,12β-dihydroxy-4,4,14α-trimethyl-3,11,15-trioxo-5α-chol-8-en-24-oic acid, 3β,7β,12β-trihydroxy-4,4,14α-trimethyl-11,15-dioxo-5α-chol-8-en-24-oic acid and 7β-hydroxy-3,11,15,23-tetraoxo-5α-lanost- 8-en-26-oic acid, respectively. 相似文献
963.
Tatsuo Tano Tsuyoshi Sugio Kazutami Imai 《Bioscience, biotechnology, and biochemistry》2013,77(3):695-696
High phytin containing particles were isolated from rice bran by a combination of a differetial centrifugation and an aqueous two phase system, using dextran 500 and polyethylene glycol 6000. The isolated particles consisted mainly of phytic acid, potassium and magnesium. The chemical composition and electron microscopic observation of the isolated particles confirmed that the electron dense material, which is embedded in aleurone particles of matured rice grains, is potassium and magnesium salts of phytic acid. 相似文献
964.
Takayuki Yamamoto Haruya Takahashi Koichiro Suzuki Akira Hirano Masanori Kamei Tsuyoshi Goto 《Bioscience, biotechnology, and biochemistry》2013,77(12):2059-2063
Several concentrations of theobromine (TB) and (?)-epicatechin (EC) were coadministered to rats, and plasma EC and its metabolites were determined using ultra-high-performance liquid chromatography–tandem mass spectrometry. It has been demonstrated that TB increases the absorption of EC in a dose-dependent manner. Cocoa powder had a similar effect, and the mechanism involved is not thought to depend on tight junctions. 相似文献
965.
Marie Takai Yuki Kozai Yukari Matsuno Maiko Fujioka Kozue Kamei 《Bioscience, biotechnology, and biochemistry》2013,77(2):238-244
Transmembrane protein CD36 binds multiple ligands, including oxidized low-density lipoproteins (oxLDLs) and long-chain fatty acids (LCFAs). Our aim was to determine whether LCFAs compete with oxLDLs for binding to CD36. We addressed this issue by examining the inhibitory effect of LCFAs against the binding of Alexa-fluor-labeled oxLDLs (AFL-oxLDL) to a synthetic peptide representing the oxLDL-binding site on CD36 (3S-CD36150–168). All of the unsaturated LCFAs tested, inhibited the binding of AFL-oxLDL to 3S-CD36150–168, albeit to varying degrees. For instance, the concentrations required for 50% inhibition of binding for oleic, linoleic, and α-linolenic acids were 0.25, 0.97, and 1.2?mM, respectively. None of the saturated LCFAs tested (e.g. stearic acid) exhibited inhibitory effects. These results suggest that at least unsaturated LCFAs can compete with oxLDLs for binding to CD36. The study also provides information on the structural requirements of LCFAs for inhibition of oxLDLs–CD36 binding. 相似文献
966.
The first step in branched-chain amino acid biosynthesis is catalyzed by acetohydroxyacid synthase (EC 2.2.1.6). This reaction involves decarboxylation of pyruvate followed by condensation with either an additional pyruvate molecule or with 2-oxobutyrate. The enzyme requires three cofactors, thiamine diphosphate (ThDP), a divalent ion, and flavin adenine dinucleotide (FAD). Escherichia coli contains three active isoenzymes, and acetohydroxyacid synthase I (AHAS I) large subunit is encoded by the ilvB gene. In this study, the ilvB gene from E. coli K-12 was cloned into expression vector pETDuet-1, and was expressed in E. coli BL21 (DH3). The purified protein was identified on a 12% SDS–PAGE gel as a single band with a mass of 65 kDa. The optimum temperature, buffer, and pH for E. coli K-12 AHAS I were 37 °C, potassium phosphate buffer, and 7.5. Km values for E. coli K-12 AHAS I binding to pyruvate, Mg+2, ThDP, and FAD were 4.15, 1.26, 0.2 mM, and 0.61 μM respectively. Inhibition of purified AHAS I protein was determined with herbicides and new compounds. 相似文献
967.
Tsuyoshi Sugio Kimihito Wada Wataru Mizunashi Kazutami Imai Tatsuo Tano 《Bioscience, biotechnology, and biochemistry》2013,77(11):2917-2918
The cDNA sequence coding for tuna growth hormone (tGH) was placed under the control of the repressible acid phosphatase (PHO5) promoter of a yeast, Saccharomyces cerevisiae, in an expression plasmid, pAM82. The yeast cells transformed with the plasmid synthesized tGH only when the cDNA was attached to the vector through a synthetic oligonucleotide linker having a similar sequence to the 5′-flanking region of the PHO5 structural region. The amount of tGH produced in yeast cells accounted for more than 3% of the total cellular protein and the product was immunologically identified as tGH by Western blotting using polyclonal antibodies specific to tGH. 相似文献
968.
969.
Jiro Arima Shota Tokai Masanori Chiba Tsuyoshi Ichiyanagi Yukinori Yabuta Nobuhiro Mori 《Bioscience, biotechnology, and biochemistry》2013,77(11):1856-1863
Pleurotus eryngii serine aminopeptidase that has peptide bond formation activity, redesignated as eryngase, was cloned and expressed. Eryngase has a family S9 peptidase unit in the C-terminal region having a catalytic triad of Ser, Asp, and His. In the phylogenetic relations among the subfamilies of family S9 peptidase (S9A, prolyl oligopeptidase; S9B, dipeptidyl peptidase; S9C, acylaminoacyl peptidase; S9D, glutamyl endopeptidase), eryngase existed alone in the neighbor of S9C subfamily. Mutation of the active site Ser524 of the eryngase with Ala eliminated its catalytic activity. In contrast, S524C mutant maintained low catalytic activity. Investigation of aminolysis activity using l-Phe-NH2 as a substrate showed that S524C mutant exhibited no hydrolysis reaction but synthesized a small amount of l-Phe-l-Phe-NH2 by the catalysis of aminolysis. In contrast, wild-type eryngase hydrolyzed the product of aminolysis l-Phe-l-Phe-NH2. Results show that the S524C mutant preferentially catalyzed aminolysis when on an l-Phe-NH2 substrate. 相似文献
970.
Purification studies were conducted on DNA polymerase bound to the membrane fraction of E. coli HF 4704. Purified enzyme (Fraction V) required Mg2+ and showed an optimun pH of 7.2. Various kinds of salt indicated a stimulative effect at concentrations lower than 0.1 m. Fraction V was unstable at an acidic condition (pH 5.0) but was rather stable at an alkaline condition (pH 9.0). The enzyme activity was lost by incubation at 45°C for 30min but was stabilized by the addition of DNA. The enzyme contained exonuclease activity but no endonuclease activity. The enzyme produced only light density DNA of various sizes. The function of this enzyme as considered to fill single stranded region of the double stranded primer DNA. 相似文献