全文获取类型
收费全文 | 1231篇 |
免费 | 80篇 |
国内免费 | 1篇 |
出版年
2023年 | 4篇 |
2022年 | 23篇 |
2021年 | 28篇 |
2020年 | 21篇 |
2019年 | 31篇 |
2018年 | 18篇 |
2017年 | 33篇 |
2016年 | 42篇 |
2015年 | 64篇 |
2014年 | 75篇 |
2013年 | 98篇 |
2012年 | 112篇 |
2011年 | 106篇 |
2010年 | 69篇 |
2009年 | 60篇 |
2008年 | 75篇 |
2007年 | 63篇 |
2006年 | 70篇 |
2005年 | 57篇 |
2004年 | 56篇 |
2003年 | 60篇 |
2002年 | 48篇 |
2001年 | 16篇 |
2000年 | 8篇 |
1999年 | 7篇 |
1998年 | 3篇 |
1997年 | 6篇 |
1995年 | 3篇 |
1994年 | 2篇 |
1993年 | 6篇 |
1992年 | 6篇 |
1991年 | 2篇 |
1990年 | 5篇 |
1989年 | 2篇 |
1988年 | 2篇 |
1987年 | 3篇 |
1984年 | 2篇 |
1983年 | 2篇 |
1982年 | 1篇 |
1981年 | 4篇 |
1980年 | 1篇 |
1979年 | 2篇 |
1977年 | 2篇 |
1976年 | 3篇 |
1975年 | 1篇 |
1974年 | 1篇 |
1973年 | 1篇 |
1972年 | 1篇 |
1971年 | 2篇 |
1969年 | 1篇 |
排序方式: 共有1312条查询结果,搜索用时 15 毫秒
1.
Gabrielle C. Winters Gianluca Polese Anna Di Cosmo Leonid L. Moroz 《Journal of morphology》2020,281(7):790-801
Neuropeptide Y (NPY) is an evolutionarily conserved neurosecretory molecule implicated in a diverse complement of functions across taxa and in regulating feeding behavior and reproductive maturation in Octopus. However, little is known about the precise molecular circuitry of NPY-mediated behaviors and physiological processes, which likely involve a complex interaction of multiple signal molecules in specific brain regions. Here, we examined the expression of NPY throughout the Octopus central nervous system. The sequence analysis of Octopus NPY precursor confirmed the presence of both, signal peptide and putative active peptides, which are highly conserved across bilaterians. In situ hybridization revealed distinct expression of NPY in specialized compartments, including potential “integration centers,” where visual, tactile, and other behavioral circuitries converge. These centers integrating separate circuits may maintain and modulate learning and memory or other behaviors not yet attributed to NPY-dependent modulation in Octopus. Extrasomatic localization of NPY mRNA in the neurites of specific neuron populations in the brain suggests a potential demand for immediate translation at synapses and a crucial temporal role for NPY in these cell populations. We also documented the presence of NPY mRNA in a small cell population in the olfactory lobe, which is a component of the Octopus feeding and reproductive control centers. However, the molecular mapping of NPY expression only partially overlapped with that produced by immunohistochemistry in previous studies. Our study provides a precise molecular map of NPY mRNA expression that can be used to design and test future hypotheses about molecular signaling in various Octopus behaviors. 相似文献
2.
Sonia Coni Silvia Maria Serrao Zuleyha Nihan Yurtsever Laura Di Magno Rosa Bordone Camilla Bertani Valerio Licursi Zaira Ianniello Paola Infante Marta Moretti Marialaura Petroni Francesca Guerrieri Alessandro Fatica Alberto Macone Enrico De Smaele Lucia Di Marcotullio Giuseppe Giannini Marella Maroder Enzo Agostinelli Gianluca Canettieri 《Cell death & disease》2020,11(12)
3.
Hanhan Liu Qiangqiang Jia Gianluca Tettamanti Sheng Li 《Insect biochemistry and molecular biology》2013,43(11):1068-1078
In the fruitfly, Drosophila melanogaster, autophagy and caspase activity function in parallel in the salivary gland during metamorphosis and in a common regulatory hierarchy during oogenesis. Both autophagy and caspase activity progressively increase in the remodeling fat body, and they are induced by a pulse of the molting hormone (20-hydroxyecdysone, 20E) during the larval-prepupal transition. Inhibition of autophagy and/or caspase activity in the remodeling fat body results in 25–40% pupal lethality, depending on the genotypes. Interestingly, a balancing crosstalk occurs between autophagy and caspase activity in this tissue: the inhibition of autophagy induces caspase activity and the inhibition of caspases induces autophagy. The Drosophila remodeling fat body provides an in vivo model for understanding the molecular mechanism of the balancing crosstalk between autophagy and caspase activity, which oppose with each other and are induced by the common stimulus 20E, and blockage of either path reinforces the other path. 相似文献
4.
C. Lapouniéroulie O. Dunda R. Ducrocq G. Trabuchet M. Mony-Lobé J. M. Bodo P. Carnevale D. Labie J. Elion R. Krishnamoorthy 《Human genetics》1992,89(3):333-337
Summary The sickle cell mutation (s) arose as at least three independent events in Africa and once in Asia, being termed the Senegal, Benin, Bantu and Indian types respectively. An investigation in Cameroon was carried out to determine whether the atypical sickle genes observed in the neighboring countries are the result of recombination or the presence of a sickle cell mutation of a different genetic origin. It was conducted on 40 homozygous SS patients followed at the Blood Transfusion Center in the capital city of Yaoundé. On 80 s chromosomes, 13 exhibited a novel polymorphic pattern that was observed three times in the homozygous state. This chromosome contains an AT gene. The restriction fragment length polymorphism haplotype is different from all the other s chromosomes in both the 5 and 3 regions, but has previously been reported in sporadic cases. The (AT)8(T)5 sequence in the — 500 region of the gene is specific and different from that of the Senegal, Benin, Bantu or Indian s genes. All the carriers of this specific chromosome belong to the Eton ethnic group and originate from the Sanaga river valley. This observation strongly argues for yet another independent origin of the sickle cell mutation in Africa, here referred to as the Cameroon type. The Benin haplotype and a Benin/ Bantu recombinant haplotype have been observed in the other studied populations: Ewondo, Bamiléké, Bassa, Yambassa and Boulou. 相似文献
5.
J. P. Lewis Marta B. Collantes E. F. Pire Nélida J. Carnevale Silvia I. Boccanelli Susana L. Stofella D. E. Prado 《Plant Ecology》1985,60(2):67-90
This paper is a survey of the vegetation of the southeastern departments in the Province of Santa Fe (Argentina). The vegetation was analyzed following Braun-Blanquet's approach modified by Mueller-Dombois & Ellenberg (1974). The most relevant species of the region were placed in 25 groups according to their requirements or general behaviour. Most of the communities are herbaceous, and apart from the woody and some other miscellaneous ones they were grouped into three ecologically and floristically defined sets. The first set, the Stipa grasslands and related communities, which are characterized by the more or less abundant presence of Stipa hyalina, Stipa neesiana and Stipa papposa, comprises five different communities. The second, the halophilous communities, comprises five communities, the two Spartina ssp. grasslands, the halophilous prairies of Distichlis spicata, the short sedge Scirpus americanus communities and the ‘pela-dales’. The third, the hygrophilous communities, comprises nine communities which are not so well defined as the ones in the other sets. Besides, two further communities have been included, the Paspalum quadrifarium and the Melica macra tall grasslands. 相似文献
6.
6-keto prostaglandin E1 (6KE) is a metabolite of PGI2, which we have shown previously inhibits spontaneous myometrial activity. In the present study we examined the effects of 6KE on uterine electrical and mechanical activity in non-pregnant ovariectomized sheep. 6KE stimulated uterine activity in a dose-dependent fashion. The effect was enhanced by pre-treatment with estradiol (E2). It was not influenced by pre-treatment with meclofenamic acid and was not associated with significant changes in the concentrations of 13,14 dihydro 15-keto PGF2 alpha in vena cava plasma. After E2 treatment, 6KE had 0.2-0.3 of the stimulatory activity of PGF2 alpha. In the absence of E2, the uterine response to both 6KE and PGF2 alpha was decreased. In animals in which spontaneous myometrial activity was inhibited by PGI2, the uterus remained responsive to 6KE. We conclude that in the ovariectomized non-pregnant sheep 6KE stimulates uterine activity, and that the effect is independent of endogenous PG production. 相似文献
7.
8.
Francesca Cappa Gianluca Caridi Giorgio Gimelli Gian Marco Ghiggeri 《Human genetics》1995,95(5):599-600
A cDNA probe of the human COL5A1 gene detects a frequent biallelic PstI polymorphism. Allele A has a frequency of 54% whereas that of allele B is 46%. This restriction fragment length polymorphism provides a useful marker for linkage analysis in 9q34.3. 相似文献
9.
A 3 1/2-year-old male with partial trisomy of the long arm of chromosome 16 resulting from a maternal balanced translocation 11p;16q is described. Clinical findings are compared with similar case reports from the literature. 相似文献
10.
J T Billheimer M Y Shen H N Carnevale H R Horton E E Jones 《Archives of biochemistry and biophysics》1979,195(2):401-413
The enzyme that catalyzes the reversible conversion of N-acetylglutamic γ-semialdehyde and l-glutamate to α-N-acetyl-l-ornithine and α-ketoglutarate, acetylornithine δ-transaminase, has been isolated in homogeneous form and crystallized from both the wild-type and the arginine-inducible strains of Escherichia coli W. The molecular weight of the wild-type transaminase is 119,000 while the molecular weight of the arginine-inducible enzyme is 61,000. However, the arginine-inducible acetylornithine δ-transaminase is not a breakdown product of the wild-type, arginine-repressible transaminase. Analysis of crude extracts of the wild-type and arginine-inducible strains by varying the acrylamide concentration in polyacrylamide disc gel electrophoresis showed that arginine-inducible and wild-type transaminases differed in ionic charge. Immunochemical analysis of the two transaminases showed that neither enzyme would cross-react with antibodies prepared against its counterpart. Treatment of the two enzymes with sodium dodecyl sulfate, followed by disc gel electrophoresis revealed that both transaminases were composed of 31,000-dalton subunits. Tryptic digestion of the two transaminases showed that nearly identical peptides were present. The overall data suggest that the wild-type and inducible transaminases were products of two different structural genes. The two transaminases have different molecular weights, ionic charges, and antigenic determinants, but both are composed of similar molecular weight subunits and show a high degree of similarity in amino acid content and peptide composition. 相似文献