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11.
Keisuke Yamano Masatomo Tagawa Evelyn Grace de Jesus Tetsuya Hirano Satoshi Miwa Yasuo Inui 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》1991,161(4):371-375
Summary To clarify the hormonal regulation of metamorphosis of the conger eel (Conger myriaster), changes in whole body concentrations of thyroid hormones, thyroxine (T4) and triiodothyronine (T3), and cortisol during metamorphosis were examined, as well as the changes in the histological activity of the thyroid gland. In larvae before metamorphosis, T4 and T3 levels were less than 5 and 0.15 ng·g-1 respectively. Levels of T4 increased to about 30 ng·g-1 during early metamorphosis, and decreased subsequently. Levels of T3 increased gradually in early metamorphosis, and then increased abruptly to about 2.0 ng·g-1 in late metamorphosis. Before metamorphosis, cortisol levels of the leptocephali less than 11 cm in total length were greater than 200 ng·g-1. Cortisol levels decreased rapidly in larger premetamorphic leptocephali, and low levels were maintained throughout the metamorphic period. Histological observation revealed an activation of the thyroid gland in early metamorphosis; thyroid follicle epithelial cells became columnar and their nuclei larger. Active uptake of colloid by these cells and intensive vascularization of the gland were also observed. By the end of metamorphosis, follicle epithelial cells became squamous, indicating a low level of glandular activity. These results suggest that thyroid hormone plays an important role in regulation of conger eel metamorphosis.Abbreviations
AL
anal length
-
TL
total length
-
T
3
triiodothyronine
-
T
4
thyroxine 相似文献
12.
Bacillus subtilis inositol dehydrogenase-encoding gene (idh): sequence and expression in Escherichia coli. 总被引:2,自引:0,他引:2
The Bacillus subtilis inositol dehydrogenase (Idh)-encoding gene (idh) was cloned in the B. subtilis temperate phage, rho 11, and then in Escherichia coli plasmids (pBR322 and pUC118). The nucleotide sequence of the idh gene, which consists of 344 codons and whose product has an Mr of 38,351, was determined. E. coli, bearing pIOL05d15, in which expression of the idh gene is under the control of the lac promoter of pUC118, overproduced an active Idh to approx. 20% of total protein upon addition of isopropyl-beta-D-thiogalactopyranoside. This overproduced enzyme cross-reacted with an anti-Idh antibody, and exhibited the same Mr and substrate specificity as those of the B. subtilis enzyme. 相似文献
13.
A nonisotopic method for determination of the in vivo activities of tyrosine hydroxylase in the rat adrenal gland 总被引:2,自引:0,他引:2
Y Hayashi S Miwa K Lee K Koshimura A Kamel K Hamahata M Fujiwara 《Analytical biochemistry》1988,168(1):176-183
A rapid and reliable method for determination of in vivo activities of tyrosine hydroxylase in the rat adrenal gland is presented. This method involves determining the rate of accumulation of 3,4-dihydroxyphenylalanine (Dopa) in the adrenal gland after decarboxylase inhibition by NSD 1015, using HPLC with electrochemical detection after purification of the acid-deproteinized tissue extract with Bio-Rex 70 columns followed by alumina batch method. Purification of the sample with alumina adsorption alone, a method usually used for purification of catecholamines and Dopa, was ineffective: epinephrine and norepinephrine, which are present in high concentrations, interfered with an accurate determination of Dopa, and dopamine, which is retained strongly on the reverse-phase column, interfered with a rapid analysis. Purification with Sephadex G-10 columns followed by alumina adsorption was also ineffective. After purification with columns of weak cation-exchange resins such as Bio-Rex 70 or Amberlite CG-50 followed by alumina adsorption, most of the epinephrine and norepinephrine was removed and dopamine was eliminated. Thus a rapid and accurate determination of Dopa could be made. Of the two cation exchangers, Bio-Rex 70 was more effective. Accumulation of Dopa in the adrenal gland was linear up to 30 min after administration of NSD 1015 and a plateau was reached with doses over 10 mg/kg. Using this method, we investigated the effects of immobilization stress, reserpine, and hypoxia on in vivo activities of tyrosine hydroxylase in the adrenal gland. 相似文献
14.
4-Nitrobenzyl [35S]mercaptan S-sulfonic acid ([35S]NBM S-sulfate), a new type of reactive metabolite of the thiol [35S]NBM in rat liver cytosol fortified with 3'-phosphoadenosine 5'-phosphosulfate, bound rapidly and covalently at pH 7.4 and 37 degrees C to the sulfhydryl groups of rat liver cytosolic proteins with formation of disulfide bonds. From the radioactive proteins was isolated and identified the sole amino acid adduct, S-([35S]NBM)cysteine, after their acid hydrolysis under the anaerobic conditions. Bovine serum albumin (BSA), a model protein with a single SH group, also reacted readily with radioactive NBM S-sulfate to form a disulfide bond in stoichiometric manner. S-([35S]NBM)-cysteine was also isolated and identified as the sole amino acid adduct from the well-washed, radioactive BSA after the same anaerobic acid hydrolysis. A normal hepatic level of GSH not only retarded the BSA-NBM adduct formation completely, but also detached the radioactivity from BSA by the reduction of the disulfide bond with formation of [35S]NBM and its disulfide. Of twenty-one amino acids examined at pH 7.4 and 37 degrees C, only cysteine reacted with NBM S-sulfate and afforded S-(NBM)cysteine with concomitant formations of S-sulfocysteine, cystine, NBM, and its disulfide. 相似文献
15.
16.
17.
6R-L-erythro-5,6,7,8-tetrahydrobiopterin as a regulator of dopamine and serotonin biosynthesis in the rat brain 总被引:5,自引:0,他引:5
6R-L-Erythro-tetrahydrobiopterin (6R-BH4), the natural isomer of tetrahydrobiopterin, was synthesized from 7,8-dihydrobiopterin using dihydrofolate reductase. The effects of intracerebroventricular injection of 6R-BH4 on the biosyntheses of neurotransmitter monoamines in the rat brain were investigated by measuring accumulation of 3,4-dihydroxyphenylalanine (DOPA) and 5-hydroxytryptophan (5-HTP) after the inhibition of aromatic L-amino acid decarboxylase by NSD 1015 and the contents of metabolites of dopamine (DA) and 5-hydroxytryptamine (5-HT). The formation of DOPA and 5-HTP increased after the injection, reached a maximum level at about 1 h, then leveled off and reached a plateau over 2 h up to 8 h. The formation of DOPA and 5-HTP increased dose-dependently in the whole brain after the injection of 6R-BH4, and reached a plateau when the dose was more than 300 micrograms/rat. The enhancement was 100 and 70% for DOPA and 5-HTP, respectively. The formation of DOPA and 5-HTP increased in four brain regions, but the degree of stimulation was different among the brain regions. The contents of DA and 5-HT metabolites increased after the injection of 6R-BH4 in all brain regions tested, especially in the diencephalon and brain stem. The contents of DA and 5-HT increased slightly after the injection of 6R-BH4. These results suggest that 6R-BH4 concentration may be submaximal within DA and 5-HT neurons, and that an increase in 6R-BH4 in the brain enhances the biosyntheses of DA and 5-HT. 相似文献
18.
Spider toxin (JSTX) on the glutamate synapse 总被引:1,自引:0,他引:1
A new neurotoxin (JSTX) was separated from spider (Nephila clavata, Joro spider) venom. JSTX irreversibly suppressed the excitatory postsynaptic potential (EPSP) and the glutamate potential in the lobster neuromuscular junction with high degree of specificity. The threshold concentration for suppressing EPSPs corresponds to a small fraction of the toxin in a venom gland, roughly estimated as low as 10(-10) M/l. 10(-10) M/l. In the giant synapse of squid stellate ganglion JSTX suppressed EPSPs without affecting the antidromic response. Glutamate-induced membrane depolarization was blocked by JSTX. In mammalian brain slice preparation, JSTX suppressed the orthodromic spike response but failed to affect on the antidromic spike in the hippocampal pyramidal neuron of CA1 and CA3 region. The above results strongly support the view that the squid giant synapse and synapses in the hippocampal pyramidal neuron are mediated by glutamate. 相似文献
19.
Homogeneous populations of hybrid alpha 3 beta 3 gamma complexes of the thermostable F1-ATPase containing one, two, or three copies of the mutationally impaired beta subunits were produced using the solid phase reconstitution method. Two kinds of mutated beta subunits were used for the reconstitution, one of which lacked the ability to bind any adenine nucleotides. The complexes containing one impaired beta and two wild-type beta subunits retained a significant amount of ATPase activity with cooperative kinetics, whereas those containing two or three impaired beta subunits showed very little ATPase activity. These results imply that the catalysis of steady-state ATP hydrolysis can proceed even if one of the three beta subunits in F1-ATPase is not functional. 相似文献
20.
C. Schönbach Kiyoshi Miwa Masaaki Ibe Hajime Shiga Kiyoshi Nokihara Masafumi Takiguchi 《Immunogenetics》1996,45(2):121-129
HLA-B*3501 is associated with subacute thyroiditis and fast progression of AIDS. An important prerequisite to investigate the T-cell
recognition of HLA-B*3501-restricted antigens is the characterization of peptide-HLA-B*3501 interactions. In this study, peptide-HLA-B*3501 interactions were determined in quantitative peptide binding assays. The results were statistically analyzed to evaluate
the influence of both anchor and nonanchor positions and the predictability of peptide binding. The binding data demonstrated
that all anchor residues at position 2 and the C-terminus found in 9-mers functioned equally as anchors in 10-mers and 11-mers.
These minimum requirements of peptide binding were refined by assessing positive and negative effects of nonanchor residues.
Aliphatic hydrophobic residues at positions 3, 5, and 8 of 10-mers and position 3 of 11-mers significantly enhanced HLA-B*3501 binding. Similar effects rendered aromatic, bulky residues, acidic or polar residues of 11-mers at position 1 as well
as at positions 4, 8, and 10, respectively. Negative effects were observed for residues carrying positively charged side-chains
at position 7 of 11-mers. The refined HLA-B*3501 peptide binding motifs enhanced the identification of potential T-cell epitopes. The disparity between positive effects
at the middle and C-terminal part (positions 5 – 8 and 10) of 11-mers and shorter peptides supports the extrusion of 11-mer
residues at positions 5, 6, and 7, away from the HLA-B*3501 binding cleft.
Received: 29 May 1996 / Revised: 5 August 1996 相似文献