全文获取类型
收费全文 | 113篇 |
免费 | 7篇 |
专业分类
120篇 |
出版年
2022年 | 1篇 |
2021年 | 1篇 |
2018年 | 2篇 |
2017年 | 5篇 |
2016年 | 4篇 |
2015年 | 4篇 |
2014年 | 8篇 |
2013年 | 5篇 |
2012年 | 6篇 |
2011年 | 8篇 |
2010年 | 11篇 |
2009年 | 7篇 |
2008年 | 4篇 |
2007年 | 6篇 |
2006年 | 4篇 |
2005年 | 7篇 |
2004年 | 4篇 |
2003年 | 4篇 |
2002年 | 7篇 |
2001年 | 2篇 |
2000年 | 2篇 |
1999年 | 2篇 |
1998年 | 2篇 |
1996年 | 1篇 |
1995年 | 2篇 |
1994年 | 3篇 |
1992年 | 3篇 |
1991年 | 1篇 |
1985年 | 1篇 |
1983年 | 1篇 |
1978年 | 1篇 |
1972年 | 1篇 |
排序方式: 共有120条查询结果,搜索用时 0 毫秒
81.
Tereza Cristina de Oliveira Borba Rosana Pereira Vianello Brondani Paulo Hideo Nakano Rangel Claudio Brondani 《Genetica》2009,137(3):293-304
The objectives of this study were to determine the genetic structure of 242 accessions from the EMBRAPA Rice Core Collection
(ERiCC), to create a mini-core collection and to develop a multiplex panel of fluorescent labeled simple sequence repeats
(SSRs). Eighty-six SSRs were used to identify 1,066 alleles, with an average number of 12.4 alleles/locus and average polymorphism
information content (PIC)/locus of 0.75. A model-based clustering method recognized the structure of the accessions on two
levels, according to their cultivation system and origin. The most divergent subgroup identified was the worldwide lowland
accessions, with the highest values for gene diversity (0.75), average Rogers distance modified by Wright (0.80), average
number of alleles/locus (11.7) and private alleles (132). A mini-core was assembled with the most divergent 24 lowland and
upland accessions. This mini-core displayed an average distance of 0.86, an average number of alleles/locus of 8.4 and an
average PIC/locus of 0.8. From the 86 SSRs, 24 were selected to compose six multiplex panels in order to optimize the process
of rice genotyping. This set of markers distinguished all 242 accessions, and showed an average PIC of 0.80 and an average
number of alleles/locus of 15.4, higher than the entire set of 86 SSRs. Since the heterogeneity found in lines and cultivars
of ERiCC was higher than expected, it is necessary to analyze pooled DNA samples to get a better estimate of genetic variability.
The SSR characterization of ERiCC clearly indicates that there is high genetic variability in rice accessions stored in genebanks
worldwide which can be promptly explored by rice pre-breeding programs. 相似文献
82.
doi: 10.1111/j.1741‐2358.2010.00444.x Undergraduate geriatric education through community service learning Introduction: Despite the exponential growth of the elderly population worldwide, geriatric education has been a formal component of only a few dental schools’ curricula. Objective: To describe the geriatric community service learning (CSL) component of the professionalism and community service (PACS) module, and to explore a CSL project carried out by a group of first year dental students at a long‐term care facility. Methods: A literature review was performed to present and describe the CSL component of the PACS module. Students’ personal reflections were used to illustrate some of the joys and challenges of experiencing a long‐term care facility environment. Results: The newly developed PACS module combines community service learning with the long‐term care experience. Students develop, apply and evaluate an educational health promotion activity in a long‐term care facility. Conclusions: The PACS module has encouraged students to acquire comprehensive knowledge and awareness of the needs and dynamics of a long‐term care as they collaboratively interacted with personnel from the facility to develop their projects. The authors would like to engage other schools in discussing the need to integrate community‐based geriatric education into their dental curricula. 相似文献
83.
Li Tang Yu Zhang Hong Pan Qiong Luo Xiao-Ming Zhu Min-Yue Dong Peter CK Leung Jian-Zhong Sheng He-Feng Huang 《Reproductive biology and endocrinology : RB&E》2009,7(1):144-8
Background
Progesterone plays an important role in the proliferation and differentiation of human endometrial cells (hECs). Large-dose treatment with progesterone has been used for treatment of endometrial proliferative disorders. However, the mechanisms behind remain unknown. 相似文献84.
Dong Wook Park Kyung-Chul Choi Colin D MacCalman Peter CK Leung 《Reproductive biology and endocrinology : RB&E》2009,7(1):81
Endometrial carcinoma is the most common neoplasm of the female genital tract, accounting for nearly one half of all gynecologic
cancers in the Western world. Although intensive research on pathological phenomena of endometrial cancer is currently going
on, but exact cause and biological aspects of this disease are not well described yet. In addition to well-documented roles
of gonadotropin-releasing hormone (GnRH) in hypopituitary ovarian (HPO) axis, the agonistic or antagonistic analogs (or both)
of GnRH have been shown to inhibit the proliferation of a variety of human gynecologic cancers. Thus, in the present study,
we further examined the possibility that GnRH induces integrin beta3 and activation of focal adhesion kinase (FAK) through
mitogen-activated protein kinases (MAPKs), ERK1/2 and p38, to inhibit the growth of HEC1A endometrial cancer cell line. As
a result, both GnRH-I and GnRH-II resulted in a significant increase in integrin beta3 expression and evoked the activation
of FAK in a time-dependent manner in these cells. In addition, these analogs induced an activation of ERK1/2 and p38 MAPK
in a time-dependent manner as downstream pathways of FAK. It appears that GnRH-II has much greater effect on the activation
of FAK, ERK1/2 and p38 compared to GnRH-I in these cells. Further, we demonstrated that the growth inhibition of HEC1A cells
by GnRH-I or GnRH-II is involved in the activation of integrin-FAK and ERK1/2 and p38 MAPK pathways. Taken together, these
results suggest that GnRH may be involved in the inhibition of endometrial cancer cell growth via activation of integrin beta3
and FAK as a direct effect. This knowledge could contribute to a better understanding of the mechanisms implicated in the
therapeutic action of GnRH and its biomedical application for the treatment against endometrial cancer. 相似文献
85.
Victor?TS?Chen Chun?Peng Peter?CK?LeungEmail author 《Reproductive biology and endocrinology : RB&E》2003,1(1):29
Activin is known to play an important regulatory role in reproduction, including pregnancy. To further examine the role and signaling mechanism of activin in regulating placental function, the steady-state level of activin type I receptor (ActRI) mRNA in immortalized extravillous trophoblasts (IEVT) cells was measured using competitive PCR (cPCR). An internal standard of ActRI cDNA for cPCR was constructed for the quantification of ActRI mRNA levels in IEVT cells. ActRI mRNA levels were increased in a dose-dependent manner by activin-A with the maximal effect observed at the dose of 10 ng/ml. Time course studies revealed that activin-A had maximal effects on ActRI mRNA levels at 6 hours after treatment. The effects of activin-A on ActRI mRNA levels was blocked by follistatin, an activin binding protein, in a dose-dependent manner. In addition, inhibin-A inhibited basal, as well as activin-A-induced ActRI mRNA levels. These findings provide evidence, for the first time, that activin-A modulates ActRI mRNA levels in human trophoblast cells. 相似文献
86.
Brondani C Rangel N Brondani V Ferreira E 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2002,104(6-7):1192-1203
Rice ( Oryza sativa) cultivar development currently faces the task of overcoming yield plateaus, which is difficult due to the narrow genetic base of breeding programs. Oryza glumaepatula is a diploid wild relative of cultivated rice, native to Central and South America, and is therefore a potential source of alleles of agronomic importance to rice breeding programs. We studied 11 agronomic traits in BC(2)F(2) families of the interspecific cross Oryza sativa x O. glumaepatula. Transgressive lines which are almost isogenic to the elite recurrent O. sativa parent were identified for most of these traits. Quantitative trait locus (QTL) analysis was performed by single-point and interval mapping using a molecular map based on 157 microsatellite and STS markers. Marker regions accounting for 14.5 to 72.9% of a phenotypic variation trait were identified in 9 of the 12 rice chromosomes. Positive QTL effects from O. glumaepatula were observed in chromosomal regions associated with tillering and panicle-number traits. 相似文献
87.
Inhibition of HIV-1 multiplication by antisense U7 snRNAs and siRNAs targeting cyclophilin A 总被引:5,自引:0,他引:5
Liu S Asparuhova M Brondani V Ziekau I Klimkait T Schümperli D 《Nucleic acids research》2004,32(12):3752-3759
Human immunodeficiency virus 1 (HIV-1) multiplication depends on a cellular protein, cyclophilin A (CyPA), that gets integrated into viral particles. Because CyPA is not required for cell viability, we attempted to block its synthesis in order to inhibit HIV-1 replication. For this purpose, we used antisense U7 small nuclear RNAs (snRNAs) that disturb CyPA pre-mRNA splicing and short interfering RNAs (siRNAs) that target CyPA mRNA for degradation. With dual-specificity U7 snRNAs targeting the 3′ and 5′ splice sites of CyPA exons 3 or 4, we obtained an efficient skipping of these exons and a strong reduction of CyPA protein. Furthermore, short interfering RNAs targeting two segments of the CyPA coding region strongly reduced CyPA mRNA and protein levels. Upon lentiviral vector-mediated transduction, prolonged antisense effects were obtained for both types of antisense RNAs in the human T-cell line CEM-SS. These transduced CEM-SS cells showed a delayed, and for the siRNAs also reduced, HIV-1 multiplication. Since the two types of antisense RNAs function by different mechanisms, combining the two approaches may result in a synergistic effect. 相似文献
88.
A flavonoid mutant of barley (Hordeum vulgare L.) exhibits increased sensitivity to UV-B radiation in the primary leaf 总被引:4,自引:2,他引:2
The aim of the present investigation was to define the role of soluble flavonoids as UV-B protectants in the primary leaf of barley (Hordeum vulgare L.). For this purpose we used a mutant line (Ant 287) from the Carlsberg collection of proanthocyanidin-free barley containing only 7% of total extractable flavonoids in the primary leaf as compared to the mother variety (Hiege 550/75). Seven-day-old leaves from plants grown under high visible light with or without supplementary UV-B radiation were used for the determination of UV-B sensitivity. UV-B-induced changes were assessed from parameters of chlorophyll fluorescence of photosystem II, including initial and maximum fluorescence, apparent quantum yield, and photochemical and non-photochemical quenching. A quartz fibre-optic microprobe was used to evaluate the amount of potentially harmful UV-B (310 nm radiation) penetrating into the leaf as a direct consequence of flavonoid deficiency. Our data indicate an essential role of flavonoids in UV-B protection of barley primary leaves. In leaves of the mutant line grown under supplementary UV-B, an increase in 310nm radiation in the mesophyll and a strong decrease in the quantum yield of photosynthesis were observed as compared to the corresponding mother variety. Primary leaves of liege responded to supplementary UV-B radiation with a 30% increase in the major flavonoid saponarin and a 500% increase in the minor compound lutonarin. This is assumed to be an efficient protective response since no changes in variable chlorophyll fluorescence were apparent. In addition, a further reduction in UV-B penetration into the mesophyll was recorded in these leaves. 相似文献
89.
Stanley CK Cheung Li-zhong Liu Lin-lin Lan Qiao-quan Liu Samuel SM Sun Juliana CN Chan Peter CY Tong 《BMC biotechnology》2011,11(1):37
Background
Human insulin-like growth factor-I (hIGF-I) is a growth factor which is highly resemble to insulin. It is essential for cell proliferation and has been proposed for treatment of various endocrine-associated diseases including growth hormone insensitivity syndrome and diabetes mellitus. In the present study, an efficient plant expression system was developed to produce biologically active recombinant hIGF-I (rhIGF-I) in transgenic rice grains. 相似文献90.
The interactive effects of ozone and light on leaf structure, carbon dioxide uptake and short-term carbon allocation of sugar maple ( Acer saccharum Marsh.) seedlings were examined using gas exchange measurements and 14 C-macroautoradiographic techniques. Two-year-old sugar maple seedlings were fumigated from budbreak for 5 months with ambient or 3 × ambient ozone in open-top chambers, receiving either 35% (high light) or 15% (low light) of full sunlight. Ozone accelerated leaf senescence, and reduced net photosynthesis, 14 CO2 uptake and stomatal conductance, with the effects being most pronounced under low light. The proportion of intercellular space increased in leaves of seedlings grown under elevated ozone and low light, possibly enhancing the susceptibility of mesophyll cells to ozone by increasing the cumulative dose per mesophyll cell. Indeed, damage to spongy mesophyll cells in the elevated ozone × low light treatment was especially frequent. 14 C macroautoradioraphy revealed heterogeneous uptake of 14 CO2 in well defined areole regions, suggesting patchy stomatal behaviour in all treatments. However, in seedlings grown under elevated ozone and low light, the highest 14 CO2 uptake occurred along larger veins, while interveinal regions exhibited little or no uptake. Although visible symptoms of ozone injury were not apparent in these seedlings, the cellular damage, reduced photosynthetic rates and reduced whole-leaf chlorophyll levels corroborate the visual scaling of whole-plant senescence, suggesting that the ozone × low light treatment accelerated senescence or senescence-like injury in sugar maple. 相似文献