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41.
Developmental changes in components of chick brain microtubule-associated protein-1 (MAP-1) and tau proteins 总被引:1,自引:0,他引:1
Microtubule proteins were purified from chick brains at various developmental stages from the 12-day embryo to adult. Three species of microtubule-associated protein-1 (MAP-1) and 5-7 molecular components of tau proteins were observed by SDS-polyacrylamide gel electrophoresis. The molecular compositions were observed to change during development of the chick brain. 相似文献
42.
Arterial perfusion of frog tongue for intracellular recording of taste cell receptor potential 总被引:1,自引:0,他引:1
Y Okada T Miyamoto T Sato 《Comparative biochemistry and physiology. A, Comparative physiology》1985,81(2):247-250
The frog tongue was perfused through its artery with a Ringer solution using a peristaltic pump, and a method was developed to record stable intracellular receptor potentials of taste cells. Perfusing at 0.05 ml/min with a Ringer solution containing 5% dextran did not cause tongue edema, but perfusing at the same rate with Ringer without dextran caused edema. After perfusion at 0.05 ml/min with 100 mM K Ringer, the membrane potential of taste cells gradually decreased and reached a constant level in about 30 min, indicating that the intercellular fluid of the tongue could be replaced within this time period. While the artery of the frog tongue was perfused at 0.05 ml/min with Ringer containing 5% dextran, intracellular receptor potentials of taste cells elicited by four basic taste stimuli (1 M NaCl, 10 mM quinine-HCl (Q-HCl), 1 mM acetic acid and 1 M galactose) were similar to those obtained from the control taste cells under normal blood flow. 相似文献
43.
Production of human c-myc protein in insect cells infected with a baculovirus expression vector. 总被引:30,自引:3,他引:27 下载免费PDF全文
C Miyamoto G E Smith J Farrell-Towt R Chizzonite M D Summers G Ju 《Molecular and cellular biology》1985,5(10):2860-2865
A cDNA fragment coding for human c-myc was inserted into the genome of the baculovirus Autographa californica nuclear polyhedrosis virus adjacent to the strong polyhedrin promoter. Insect cells infected with the recombinant virus produced significant amounts of c-myc protein, which constituted the major phosphoprotein component in these cells. By immunoprecipitation and immunoblot analysis, two proteins of 61 and 64 kilodaltons were detected with c-myc-specific antisera. The insect-derived proteins were compared with recombinant human c-myc-encoded proteins synthesized in Escherichia coli and Saccharomyces cerevisiae cells. The c-myc gene product was found predominantly in the nucleus by subcellular fractionation of infected insect cells. 相似文献
44.
T Ikehara H Yamaguchi K Hosokawa M Kaku H Miyamoto 《Journal of cellular biochemistry》1985,28(4):273-280
phenazine methosulfate (PMS) stimulates ouabain-sensitive Rb+ uptake by HeLa cells. This stimulation cannot be attributed to the effect of the dye on the intracellular Na+ or ATP content. Respiratory inhibitors, such as 5 mM NaCN and 5 microM rotenone, and anaerobic conditions enhance the stimulation of Rb+ uptake by PMS. Cellular respiration is stimulated, but lactate production is reduced in the presence of PMS, irrespective of the presence of respiratory inhibitors. Cellular NADH is oxidized markedly on addition of PMS plus inhibitors, but it is not affected by addition of the inhibitors only. In the presence of a high concentration of PMS, PMS-stimulated ouabain-sensitive Rb+ uptake is inhibited by addition of ascorbate. From these results it is concluded that Na+K-pump activity is closely related to the cellular redox state. 相似文献
45.
A Ca2+, calmodulin-dependent protein kinase from rat brain with a MW of 640,000 phosphorylated calmodulin-sensitive phosphodiesterase from the brain cytosol. The Km of the enzyme for the phosphodiesterase was 5.0 microM and the Vmax was 212 nmol/mg/min. The amount of phosphate incorporated into the phosphodiesterase was 0.7 mol/mol subunit. Phosphorylation of the phosphodiesterase enhanced the enzyme activity by about 20% for hydrolysis of a higher concentration of cyclic AMP. 相似文献
46.
Hitoshi Sato Yuichi Sugiyama Yasufumi Sawada Tatsuji Iga Manabu Hanano 《Life sciences》1984,35(10):1051-1059
A rapid radioreceptor assay for measuring ß-endorphin (ß-EP) in unextracted serum has been developed. The method is based upon the inhibition by ß-EP of 3H-naloxone binding to the specific receptors on rat brain membranes, prepared in a stable form of pellets. Effect of serum on the assay was minimized by adding pooled serum to the equal dilution of total serum in the assay mixture. Pharmacokinetic analysis of pharmacologically active ß-EP equivalents (ß-EP eq.) in rats was performed using this method. The serum disappearance of ß-EP eq. after iv administration followed a biexponential decline and pharmacokinetic parameters were calculated by a two-compartment open model. The half-lives of α-phase and ß-phase were 2.6 ± 0.5 min and 6.2 ± 1.6 hr (mean ± SE; n=6), respectively. The volume of the central compartment (V1) and that of steady-state (Vdss) were 67 ± 16 and 480 ± 75 ml/kg (mean ± SE; n=6), respectively. The total body serum clearance (CLtot) was 2.1 ± 0.9 ml/min/kg (mean ± SE; n=6). The serum disappearance curve of ß-EP eq. obtained in the present study was similar to that previously reported by Houghten et al. (Proc. Natl. Acad. Sci. U.S.A. , 4588–4591 (1980)), in which the disapperance of total radioactivity of tritiated ß-EP in rats was examined. 相似文献
47.
The effect of reovirus double-stranded RNA (dsRNA) and 5'-O-monophosphate form of 2',5'-oligoadenylate (pA(2'p5'A)2) on the translation and degradation of reovirus messenger RNA and on protein phosphorylation was examined in extracts prepared from interferon-treated mouse L fibroblasts. The following results were obtained. 1) The enhanced degradation of reovirus [3H]mRNA observed in the presence of either dsRNA or the 5'-O-triphosphate form of 2',5'-oligoadenylate (pppA(2'p5'A)3) was completely blocked by pA(2'p5'A)2. 2) The dsRNA-dependent phosphorylation of protein P1 and the alpha subunit of eukaryotic initiation factor (eIF-2) depended in a similar manner upon the concentration of dsRNA and was optimal at low dsRNA concentrations (0.1 to 1 microgram/ml). However, high concentrations of dsRNA (greater than 100 micrograms/ml) drastically reduced the phosphorylation of both P1 and eIF-2 alpha. Neither P1 nor eIF-2 alpha phosphorylation was affected by either pA(2'p5'A)2 or pppA(2'p5'A)3. 3) The translation of reovirus mRNA in vitro was inhibited by the addition of either low concentrations of dsRNA or pppA(2'p5'A)3. Whereas pA(2'p5'A)2 completely reversed the pppA(2'p5'A)3-mediated inhibition of translation, the inhibition mediated by low concentrations of dsRNA was only partially reversed by pA(2'p5'A)2. Under conditions where the pppA-(2'p5'A)3mediated degradation of reovirus mRNA was blocked, the translation of reovirus mRNA was still inhibited by low but not by high concentrations of dsRNA in a manner that correlated with the activation of P1 and eIF-2 alpha phosphorylation. These results suggest that the pppA(2'p5'A)n-dependent ribonuclease is not required and that protein phosphorylation may indeed be sufficient for the dsRNA-dependent inhibition of reovirus mRNA translation in cell-free systems derived from interferon-treated mouse fibroblasts. 相似文献
48.
K Higashi K Fukunaga K Matsui M Maeyama E Miyamoto 《Biochimica et biophysica acta》1983,747(3):232-240
Myosin light-chain kinase was purified from porcine myometrium to apparent homogeneity at about 262-fold with an Mr of 130 000 as determined by SDS-polyacrylamide gel electrophoresis and a sedimentation coefficient of 4.5 S. The approximate content of the soluble myosin light-chain kinase was estimated to be about 0.85 microM. The purified enzyme exhibited strict substrate specificity only for 20-kDa myosin light chain and Ka values of 0.6 nM and 0.3 microM for calmodulin and Ca2+, respectively. The enzyme was phosphorylated by the catalytic subunit of cyclic AMP-dependent protein kinase, which resulted in a decrease in the affinity for calmodulin of 4-7-fold without effect on the Vmax. The maximal amount of phosphate incorporated into the enzyme was 0.5-0.8 and 1.0-1.4 mol per mol of the enzyme in the presence and absence of Ca2+ and calmodulin, respectively. In the presence of a subsaturating concentration of calmodulin, the enzyme showed a lower sensitivity for Ca2+ by phosphorylation. 相似文献
49.
Abstract: The higher-molecular-weight elongation factor-1 (EF-1H) of the chick brain was observed to contain three subunits (denominated α, β, and γ), contrary to a previous report that the brain EF-1H consisted of aggregates of low-molecular-weight elongation factor- 1 (EF-1L). Crude EF-1H, obtained from 20-day embryonic brain, was treated with 0.4 M ammonium chloride and 0.1 mM GTP, and EF-1βγ, was obtained using a DEAE-Sephadex column equilibrated in 0.025 mM GTP. Both EF-1β, and EF-1γ, were isolated by means of a DE-52 column equilibrated in 6 M urea and were found to have molecular weights of 2.8 and 4.8 × 104, respectively. EF-1β and EF-1γ were also obtained from young rat and calf brains by the same procedures. The molecular weight of the isolated EF-1α was 5 × 104. It was found that EF-1β stimulated the two EF-1α-dependent reactions, i.e., phenylalanyl-tRNA binding (reaction 1) and polyphenylalanine synthesis (reaction 2), and also stimulated the nucleotide exchange reaction in the EF- 1α-guanine nucleotide binary complex (reaction 3). The degrees of stimulation of reactions 1, 2, and 3 by the addition of EF-1β were 2 to 3 times, about 18 times, and 2 to 3 times as much as with EF-1α alone, respectively. The amino acid compositions of EF-1α -1β, and -1γ and EF-2 were very similar to those of other eukaryotic tissues. Thus the constituents and properties of EFs of the brain were found to be basically similar to those of other tissues of eukaryotes, although EF-1β, and EF-1, had not been reported in the brain. A possible physiological significance of EF-1β during brain development is also discussed. 相似文献
50.
Alleviation of Aluminum Stress and Stimulation of Tea Pollen Tube Growth by Fluorine 总被引:2,自引:0,他引:2
Aluminum (Al) and fluorine (F) were found to affect tea pollentube growth on an agar medium. Not only was the growth stronglyrepressed by increasing Al content of the medium but it wasalso distinctly affected by declining pH from 5.2 to 4.4. Additionof 0.2 mM Al as Al2(SO4)3 to a pH 4.6 medium containing 1.2%agar, 8% sucrose and 17 ppm boron remarkably repressed tea pollentube growth. However, NaF added to medium containing Al clearlyalleviated the growth inhibition. This effect was observed with0.2 mM and 0.4 HIM NaF, and the presence of 0.6 mM and 1.2 DIMNaF with 0.2 mM Al even produced a stimulatory effect. Treatmentwith NaF alone significantly stimulated growth at pH 4.6 and5.2. These results indicate that Al-F complexes have a favorablerather than adverse effect on tea pollen tube growth. (Received November 22, 1982; Accepted April 20, 1983) 相似文献