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排序方式: 共有92条查询结果,搜索用时 15 毫秒
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Raphael B. Costa Gregório MF Camargo Iara DPS Diaz Natalia Irano Marina M. Dias Roberto Carvalheiro Arione A. Boligon Fernando Baldi Henrique N. Oliveira Humberto Tonhati Lucia G. Albuquerque 《遗传、选种与进化》2015,47(1)
Background
An important goal of Zebu breeding programs is to improve reproductive performance. A major problem faced with the genetic improvement of reproductive traits is that recording the time for an animal to reach sexual maturity is costly. Another issue is that accurate estimates of breeding values are obtained only a long time after the young bulls have gone through selection. An alternative to overcome these problems is to use traits that are indicators of the reproductive efficiency of the herd and are easier to measure, such as age at first calving. Another problem is that heifers that have conceived once may fail to conceive in the next breeding season, which increases production costs. Thus, increasing heifer’s rebreeding rates should improve the economic efficiency of the herd. Response to selection for these traits tends to be slow, since they have a low heritability and phenotypic information is provided only later in the life of the animal. Genome-wide association studies (GWAS) are useful to investigate the genetic mechanisms that underlie these traits by identifying the genes and metabolic pathways involved.Results
Data from 1853 females belonging to the Agricultural Jacarezinho LTDA were used. Genotyping was performed using the BovineHD BeadChip (777 962 single nucleotide polymorphisms (SNPs)) according to the protocol of Illumina - Infinium Assay II ® Multi-Sample HiScan with the unit SQ ™ System. After quality control, 305 348 SNPs were used for GWAS. Forty-two and 19 SNPs had a Bayes factor greater than 150 for heifer rebreeding and age at first calving, respectively. All significant SNPs for age at first calving were significant for heifer rebreeding. These 42 SNPs were next or within 35 genes that were distributed over 18 chromosomes and comprised 27 protein-encoding genes, six pseudogenes and two miscellaneous noncoding RNAs.Conclusions
The use of Bayes factor to determine the significance of SNPs allowed us to identify two sets of 42 and 19 significant SNPs for heifer rebreeding and age at first calving, respectively, which explain 11.35 % and 6.42 % of their phenotypic variance, respectively. These SNPs provide relevant information to help elucidate which genes affect these traits. 相似文献63.
L Pirtoli G Risso P Inaudi F Landoni F Pepi M Bindi E Tucci N D'Antona C Mangioni 《The International journal of biological markers》1991,6(2):107-114
The management of advanced stage ovarian carcinomas is presently based on initial surgical debulking, multiple drug chemotherapy including cisplatinum, second-look laparotomy. Such an aggressive approach has improved objective response rates and expected survival time, but no dramatic change has been demonstrated as for definitive cure percentages. Many Authors have attempted to turn an optimal objective response to chemotherapy (no residual or minimal residual disease at second-look) into a definitive cure with irradiation. Some reports show satisfactory results, but a high incidence of bowel obstructive complications has been demonstrated, probably due to multiple surgical manipulations before radiotherapy. A reliable diagnostic tool, that could help to avoid the second-look laparotomy (whose inherent role in improving survival is not assessed) should be therefore useful. The possible role of serum tumor markers determinations, for this purpose, is here discussed on the ground of a series of 20 patients affected by stage III ovarian carcinoma. Following this experience, a valuable role seems attributable to CA 125 in monitoring tumor response. Patients achieving values under 35 U/ml before second-look laparotomy showed tumor residuals in the range O-microscopic- less than 1 cm., that is, neoplastic localizations reliable for consolidation radiation therapy. 相似文献
64.
Eduardo?M?Del Aguila Marcio?B?Dutra Joab?T?Silva Vania?MF?PaschoalinEmail author 《BMC molecular biology》2005,6(1):9
Background
Preparation of RNA free from DNA is a critical step before performing RT-PCR assay. Total RNA isolated from several sources, including those obtained from Saccharomyces cerevisiae, using routine methodologies are frequently contaminated with DNA, which can give rise to amplification products that mimic the amplicons expected from the RNA target. 相似文献65.
Eduardo?S?SilvaEmail author Gerard?J?Schoone Celia?MF?Gontijo Reginaldo?P?Brazil Raquel?S?Pacheco Henk?DFH?Schallig 《Kinetoplastid biology and disease》2005,4(1):4
Background
The direct agglutination test (DAT) has proved to be a very important sero-diagnostic tool combining high levels of intrinsic validity and ease of performance. Otherwise, fast agglutination screening test (FAST) utilises only one serum dilution making the test very suitable for the screening of large populations. 相似文献66.
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Margarida Cepa Georgina Correia-da-Silva Elisiário J Tavares da Silva Fernanda MF Roleira Margarida Borges Natércia A Teixeira 《BMC cell biology》2008,9(1):41
Background
Aromatase, the cytochrome P-450 enzyme (CYP19) responsible for estrogen biosynthesis, is an important target for the treatment of estrogen-dependent breast cancer. In fact, the use of synthetic aromatase inhibitors (AI), which induce suppression of estrogen synthesis, has shown to be an effective alternative to the classical tamoxifen for the treatment of postmenopausal patients with ER-positive breast cancer. New AIs obtained, in our laboratory, by modification of the A and D-rings of the natural substrate of aromatase, compounds 3a and 4a, showed previously to efficiently suppress aromatase activity in placental microsomes. In the present study we have investigated the effects of these compounds on cell proliferation, cell cycle progression and induction of cell death using the estrogen-dependent human breast cancer cell line stably transfected with the aromatase gene, MCF-7 aro cells. 相似文献70.