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201.
Phosphorylation of a sugar-specific protein component of the lactose transport system in Staphylococcus aureus 总被引:3,自引:0,他引:3
T Nakazawa R D Simoni J B Hays S Roseman 《Biochemical and biophysical research communications》1971,42(5):836-843
A sugar-specific component of the lactose transport system in Staphylococcus aureus, Factor IIIlac, is phosphorylated as an intermediate in the over-all transfer of a phosphoryl group from PEP to lactose. P-IIIlac is isolated and shown to be a substrate for the final phosphoryl transfer reaction to sugar, catalyzed by Enzyme IIlac. 相似文献
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M Simoni A Velardo V Montanini M Faustini Fustini S Seghedoni P Marrama 《Hormone research》1990,33(5):184-189
The circannual rhythm of plasma thyrotropin (TSH) was evaluated in 8,310 euthyroid, serially independent, young, middle-aged and old men and women. A statistically significant circannual rhythm of plasma TSH was validated, by the mean group-cosinor method, in the middle-aged and old men and women (p less than 0.05), with acrophase in December, whereas the young subjects did not show any rhythm. No significant correlation was found between TSH plasma levels and free thyroxine (fT4) or ambient temperature in any group. Moreover, plasma fT4 did not show seasonal variations. 相似文献
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Rosa Rugani Laura Fontanari Eleonora Simoni Lucia Regolin Giorgio Vallortigara 《Proceedings. Biological sciences / The Royal Society》2009,276(1666):2451-2460
Newly hatched domestic chicks were reared with five identical objects. On days 3 or 4, chicks underwent free-choice tests in which sets of three and two of the five original objects disappeared (either simultaneously or one by one), each behind one of two opaque identical screens. Chicks spontaneously inspected the screen occluding the larger set (experiment 1). Results were confirmed under conditions controlling for continuous variables (total surface area or contour length; experiment 2). In the third experiment, after the initial disappearance of the two sets (first event, FE), some of the objects were visibly transferred, one by one, from one screen to the other (second event, SE). Thus, computation of a series of subsequent additions or subtractions of elements that appeared and disappeared, one by one, was needed in order to perform the task successfully. Chicks spontaneously chose the screen, hiding the larger number of elements at the end of the SE, irrespective of the directional cues provided by the initial (FE) and final (SE) displacements. Results suggest impressive proto-arithmetic capacities in the young and relatively inexperienced chicks of this precocial species. 相似文献
208.
Pastorini E Locatelli M Simoni P Roda G Roda E Roda A 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》2008,872(1-2):99-106
A new HPLC method for the determination of 5-aminosalicylic acid (5-ASA) and N-acetyl-5-aminosalicylic acid (N-Ac-5-ASA) in human plasma was developed and validated. Plasma samples were analyzed after protein precipitation with methanol and the two analytes were separated using a C18 column with a mobile phase composed of 17.5mmol/L acetic acid (pH 3.3):acetonitrile=85:15 (v/v) at 0.2mL/min flow rate. 4-ASA and N-Ac-4-ASA were used as internal standards. Selective detection was performed by tandem mass spectrometry with electrospray source, operating in negative ionization mode and in multiple reaction monitoring acquisition (m/z 152-->108 for 5-ASA; m/z 194-->150 and 194-->107 for N-Ac-5-ASA). The limit of quantification (LOQ) was 50ng/mL for both analytes (0.2ng injected) and matrix-matched standard curves showed linearity up to 4000ng/mL. In the entire analytical range the within- and between-batch precision (R.S.D.%) values were respectively =6.3% and =11% for 5-ASA and =8.0% and =10% for N-Ac-5-ASA. For both analytes the within- and between-batch accuracy (bias%) values ranged respectively from -8.4% to 7.9% and from -7.9% to 8.0%. The overall recoveries (n=6) at three tested concentration levels (i.e. 100, 1000 and 4000ng/mL) were respectively >90% for 5-ASA and >95% for N-Ac-5-ASA (R.S.D.%=10%). The method was applied to evaluate the pharmacokinetic of 5-ASA after a single oral dose administration of this compound (1200mg) to 24 healthy volunteers. The mean maximum concentration levels were 680ng/mL for 5-ASA and 1240ng/mL for N-Ac-5-ASA and the kinetic profiles were in agreement with previous studies. 相似文献
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3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGR) is the rate-limiting enzyme in the cholesterol biosynthetic pathway. This endoplasmic reticulum membrane protein contains a cytosolic catalytic domain and a transmembrane domain with eight membrane spans that are necessary for sterol-accelerated degradation. Competition experiments showed that wild-type transmembrane domains of HMGR and sterol regulatory element binding protein cleavage-activating protein (SCAP) blocked sterol-accelerated degradation of intact HMGR and HMGal, a model protein containing the membrane domain of HMGR linked to Escherichia coli beta-galactosidase. However, mutant transmembrane domains of HMGR and SCAP whose sterol-sensing functions were abolished did not inhibit sterol-accelerated degradation of HMGR and HMGal. In addition, our mutagenesis studies on HMGal indicated that four Phe residues conserved in span 6 of HMGR and the sterol-sensing domains of other sterol-related proteins are required for the regulated degradation of HMGR. These results suggest that HMGR and SCAP compete for binding to a sterol-regulated regulator protein, and this binding may need the four Phe residues. 相似文献
210.