全文获取类型
收费全文 | 310篇 |
免费 | 21篇 |
出版年
2022年 | 5篇 |
2021年 | 5篇 |
2019年 | 2篇 |
2018年 | 7篇 |
2016年 | 8篇 |
2015年 | 13篇 |
2014年 | 21篇 |
2013年 | 23篇 |
2012年 | 20篇 |
2011年 | 17篇 |
2010年 | 10篇 |
2009年 | 9篇 |
2008年 | 17篇 |
2007年 | 5篇 |
2006年 | 9篇 |
2005年 | 8篇 |
2004年 | 6篇 |
2003年 | 6篇 |
2002年 | 10篇 |
2001年 | 5篇 |
2000年 | 5篇 |
1999年 | 5篇 |
1998年 | 8篇 |
1997年 | 4篇 |
1996年 | 5篇 |
1995年 | 1篇 |
1993年 | 3篇 |
1992年 | 5篇 |
1991年 | 5篇 |
1990年 | 5篇 |
1989年 | 9篇 |
1988年 | 7篇 |
1987年 | 6篇 |
1986年 | 1篇 |
1985年 | 5篇 |
1984年 | 5篇 |
1983年 | 9篇 |
1982年 | 1篇 |
1981年 | 2篇 |
1980年 | 2篇 |
1979年 | 5篇 |
1978年 | 2篇 |
1977年 | 3篇 |
1976年 | 3篇 |
1975年 | 4篇 |
1974年 | 9篇 |
1973年 | 1篇 |
1971年 | 1篇 |
1970年 | 1篇 |
1969年 | 1篇 |
排序方式: 共有331条查询结果,搜索用时 0 毫秒
41.
Javier Ca?ón Paolo Alexandrino Isabel Bessa Carlos Carleos Yolanda Carretero Susana Dunner Nuno Ferran David Garcia Jordi Jordana Denis Lalo? Albano Pereira Armand Sanchez Katayoun Moazami-Goudarzi 《遗传、选种与进化》2001,33(3):311-332
This study was undertaken to determine the genetic structure, evolutionary relationships, and the genetic diversity among 18 local cattle breeds from Spain, Portugal, and France using 16 microsatellites. Heterozygosities, estimates of Fst, genetic distances, multivariate and diversity analyses, and assignment tests were performed. Heterozygosities ranged from 0.54 in the Pirenaica breed to 0.72 in the Barrosã breed. Seven percent of the total genetic variability can be attributed to differences among breeds (mean Fst = 0.07; P < 0.01). Five different genetic distances were computed and compared with no correlation found to be significantly different from 0 between distances based on the effective size of the population and those which use the size of the alleles. The Weitzman recursive approach and a multivariate analysis were used to measure the contribution of the breeds diversity. The Weitzman approach suggests that the most important breeds to be preserved are those grouped into two clusters: the cluster formed by the Mirandesa and Alistana breeds and that of the Sayaguesa and Tudanca breeds. The hypothetical extinction of one of those clusters represents a 17% loss of diversity. A correspondence analysis not only distinguished four breed groups but also confirmed results of previous studies classifying the important breeds contributing to diversity. In addition, the variation between breeds was sufficiently high so as to allow individuals to be assigned to their breed of origin with a probability of 99% for simulated samples. 相似文献
42.
43.
E. Chiarpotto F. Biasi M. Aragno A. Scavazza O. Danni E. Albano G. Poli 《Cell biochemistry and function》1993,11(1):71-75
The combination of carbon tetrachloride (CCl4) and 1,2-dibromoethane (DBE) in isolated rat hepatocytes led to a significant potentiation of both lipid peroxidation and of plasma membrane damage observed after a single treatment with CCl4. Such a synergistic effect appeared to be related to the CCl4-induced shift of DBE metabolism from the cytosolic conjugation with glutathione towards the microsomal transformation into toxic intermediates. In fact, CCl4 significantly inactivated hepatocyte total GSH-transferase, i.e. the DBE detoxification pathway. Furthermore, while the microsomal metabolism of CCl4 was not affected by the simultaneous presence of DBE, the amount of DBE reactive metabolities covalently bound to hepatocyte protein was significantly enhanced in the presence of CCl4. 相似文献
44.
Marcin Górecki Maria Annunziata M. Capozzi Gianluigi Albano Cosimo Cardellicchio Lorenzo Di Bari Gennaro Pescitelli 《Chirality》2018,30(1):29-42
Three β‐keto sulfoxides ( 1–3 ) were synthesized in enantiopure form and investigated by means of circular dichroism (CD) spectroscopy, both in electronic and vibrational range (ECD, VCD), in combination with quantum chemical calculations. For compound 2 , the X‐ray structure was available; thus, the ECD in the solid state was also considered to reveal the differences between the molecular species in both states. Despite the simplicity of all β‐keto sulfoxides under investigation (29 atoms), reproducing even the major spectral VCD features failed for two compounds, making the use of VCD not ideal to assign their absolute configuration in a reliable way. We demonstrated, however, that the use of ECD spectroscopy, both in solution and solid state, can easily, unambiguously, and without any complication simulate all bands by applying the standard protocol for calculations. This study may stimulate the debate on the need of the use of two chiroptical methods simultaneously in the determination of absolute configurations. 相似文献
45.
An updated checklist of the vascular flora native to Italy 总被引:1,自引:0,他引:1
F. Bartolucci L. Peruzzi G. Galasso A. Albano A. Alessandrini N. M. G. Ardenghi 《Plant biosystems》2018,152(2):179-303
An updated inventory of the native vascular flora of Italy, providing details on the occurrence at regional level, is presented. The checklist includes 8195 taxa (6417 species and 1778 subspecies), distributed in 1092 genera and 152 families; 23 taxa are lycophytes, 108 ferns and fern allies, 30 gymnosperms and 8034 angiosperms. The taxa currently occurring in Italy are 7483, while 568 taxa have not been confirmed in recent times, 99 are doubtfully occurring in the country and 19 are data deficient. Out of the 568 not confirmed taxa, 26 are considered extinct or possibly extinct. 相似文献
46.
Changes in odor quality discrimination following recovery from olfactory nerve transection 总被引:4,自引:2,他引:2
Following recovery from olfactory nerve transection, animals regain their
ability to discriminate between odors. Odor discrimination is restored
after new neurons establish connections with the olfactory bulb. However,
it is not known if the new connections alter odor quality perception. To
address this question, 20 adult hamsters were first trained to discriminate
between cinnamon and strawberry odors. After reaching criterion (> or =
90% correct response), half of the animals received a bilateral nerve
transection (BTX) and half a surgical sham procedure. Animals were not
tested again until day 40, a point in recovery when connections are
re-established with the bulb. When BTX animals were tested without food
reinforcement, they could not perform the odor discrimination task. Sham
animals, however, could discriminate, demonstrating that the behavioral
response had not been extinguished during the 40 day period. When
reinforcement was resumed, BTX animals were able to discriminate between
cinnamon and strawberry after four test sessions. In addition, their
ability to discriminate between these two familiar odors was no different
than that of BTX and sham animals tested with two novel odors, baby powder
and coffee. These findings suggest that, after recovery from nerve
transection, there are alterations in sensory perception and that
restoration of odor quality discrimination requires that the animal must
again learn to associate individual odor sensations with a behavioral
response.
相似文献
47.
Brodfuehrer PD McCormick K Tapyrik L Albano AM Graybeal C 《Invertebrate neuroscience : IN》2008,8(1):31-39
Higher-order projection interneurons that function in more than one behavior have been identified in a number of preparations.
In this study, we document that stimulation of cell Tr1, a previously identified trigger interneuron for swimming in the medicinal
leech, can also elicit the motor program for crawling in isolated nerve cords. We also show that motor choice is independent
of the firing frequency of Tr1 and amount of spiking activity recorded extracellularly at three locations along the ventral
nerve cord prior to Tr1 stimulation. On the other hand, during Tr1 stimulation there is a significant difference in the amount
of activity elicited in the ventral nerve cord that correlates with the motor program activated. On average, Tr1 stimulation
trials that lead to crawling elicit greater amounts of activity than in trials that lead to swimming. 相似文献
48.
Relationships between bacterial diversity and environmental variables in a tropical marine environment, Rio de Janeiro 总被引:6,自引:0,他引:6
Vieira RP Gonzalez AM Cardoso AM Oliveira DN Albano RM Clementino MM Martins OB Paranhos R 《Environmental microbiology》2008,10(1):189-199
This study is the first to apply a comparative analysis of environmental chemistry, microbiological parameters and bacterioplankton 16S rRNA clone libraries from different areas of a 50 km transect along a trophic gradient in the tropical Guanabara Bay ecosystem. Higher bacterial diversity was found in the coastal area, whereas lower richness was observed in the more polluted inner bay water. The significance of differences between clone libraries was examined with libshuff statistics. Paired reciprocal comparisons indicated that each of the libraries differs significantly from the others, and this is in agreement with direct interpretation of the phylogenetic tree. Furthermore, correspondence analyses showed that some taxa are related to specific abiotic, trophic and microbiological parameters in Guanabara Bay estuarine system. 相似文献
49.
Tiago Antao Ana Lopes Ricardo J Lopes Albano Beja-Pereira Gordon Luikart 《BMC bioinformatics》2008,9(1):323
Background
Testing for selection is becoming one of the most important steps in the analysis of multilocus population genetics data sets. Existing applications are difficult to use, leaving many non-trivial, error-prone tasks to the user. 相似文献50.
Platteau P.; Desmet B.; Odoma G.; Albano C.; Devroey P.; Sali E. Tamale 《ESHRE Monographs》2008,2008(1):90-92
4Correspondence address. Zonlaan 49, 1700 Dilbeek, Belgium. E-mail: peterplatteau{at}telenet.be We all know that starting and running an ART clinic is not soeasy as some people might perceive from outside. Doing the samething in the middle of Africa is even more challenging as someevidences in the Western world are not so obvious in this partof the world. We started our clinic in Kampala in 2004. Theclinic was a converted apartment from a four flat building.In the beginning, we had difficulties with importing drugs,culture media and consumables; we had the feeling everybodywas against us. We overcame multiple power failures, night intrudersand a 20% masturbation failure, but once the first IVF/ICSIbabies were born, people started to believe in the project.At present, 250 IVF/ICSI cycles a year are done in batches,we have a successful embryo freezing programme, offer IUI/ICSIfor sero discordant HIV couples and have the first babies afterIVF, ICSI, testicular biopsy, embryo freezing, oocyte donationand surrogacy in Central Africa. The results are comparableto the ones in the Western world. 相似文献