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461.
462.
Nicola Ricci Fulvio Esposito Renzo Nobili Roberto Revoltella 《Journal of cellular physiology》1976,88(3):363-370
PHA, Con-A, or anti-tubulin antibodies inhibit homotypic pair formation, in B. intermedium mating type-I cells in the presence of suboptimal concentrations of gamone II. The inhibition is dependent on the dose of gamone added; the structural conformation and the relative concentration of the inhibitor; and the time of addition of the inhibitor. The block can be selectively prevented by competitive inhibitors of each ligand. The receptors for the inhibitors are distinctive and there is no cross-reaction between the ligands. It is concluded that ligand binding and subsequent receptor-ligand aggregation must induce a change within the cell-surface membrane, which distorts the distribution and/or affects an optimal conformational aspect of a specific membrane-receptor system for the gamone, a prerequisite for cell pair formation. 相似文献
463.
464.
The aim of the present study was to investigate the pituitary-thyroid axis function during the long-term (30 days) intramuscular administration of 4 mg/day of thyrotropin-releasing hormone tartrate (TRH-T) in 15 patients with spinocerebellar degeneration. The study was performed as follows: (1) acute 4 mg TRH-T test with hourly prolactin (PRL) and thyroid-stimulating hormone (TSH) level evaluations for 6 h; (2) placebo; and (3) 4 mg/day of TRH-T administration for 30 days with TSH, PRL, and free T3 and T4 (FT3 and FT4) levels evaluated on days 1, 15 and 30. Hormone determination was performed just before and 1 h after placebo or TRH-T administration. The acute administration of TRH-T caused a sustained rise of TSH which lasted until the 6th hour and of PRL which declined after 1 h (p < 0.01). During placebo administration, no change of TSH, PRL, FT3 or FT4 was observed. On the 1st day of treatment, 1 h after the TRH-T injection, a significant increase of both TSH and PRL levels occurred (p < 0.01). As compared to the 1st day, a significant decrease of the TSH (p < 0.01) levels occurred on the 15th and 30th days before TRH-T: the TSH response to TRH-T administration was present although less than on the 1st day (p < 0.01). Moreover, throughout the whole period of treatment, no difference was recorded for PRL levels before or after TRH-T administration.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
465.
Emidio Albertini Renzo Torricelli Elena Bitocchi Lorenzo Raggi Gianpiero Marconi Luciano Pollastri Gabriella Di Minco Alfredo Battistini Roberto Papa Fabio Veronesi 《Molecular breeding : new strategies in plant improvement》2011,27(4):533-547
The olive is considered one of the most important fruit crops of the Mediterranean basin where it shows a wide range of variability,
with about 2,000 cultivars. Italy, with about 500 cultivars, plays a fundamental role. The ability to discriminate olive cultivars
and estimate genetic variability are important factors in better management of genetic resources and in helping to understand
how genetic diversity is partitioned among cultivars. The two main objectives of the present investigation were to evaluate
the identity of cultivars grown in Abruzzo region, central Italy, and to study their genetic structure. We applied amplified
fragment length polymorphism (AFLP) methodology on 84 genotypes belonging to the most relevant and oldest varieties cultivated
in Abruzzo and on six unknown genotypes. The information content of data was evaluated using the Marker Ratio index and the
Polymorphic Index Content. Moreover, STRUCTURE software was used to investigate the genetic population structure. The analysis
enabled us to clearly distinguish eight cultivars within seven clusters. Additionally, one cluster was found to have various
minor cultivars and showed a relatively high level of diversity. The partitioning of genetic diversity showed that the largest
amount of molecular variance was within groups. Our data suggest that both sexual and clonal propagation have played an important
role in the evolution of olive cultivars. In our hypothesis, some ancestral population spread in central Italy with a relevant
role of seed propagation, followed by a selection of superior clones from which more traditional varieties originated. In
a few cases, hybridization should be taken into consideration to explain the diffusion of recently developed cultivars. 相似文献