全文获取类型
收费全文 | 1382篇 |
免费 | 81篇 |
国内免费 | 3篇 |
出版年
2022年 | 9篇 |
2021年 | 17篇 |
2020年 | 11篇 |
2019年 | 14篇 |
2018年 | 18篇 |
2017年 | 25篇 |
2016年 | 44篇 |
2015年 | 68篇 |
2014年 | 51篇 |
2013年 | 87篇 |
2012年 | 112篇 |
2011年 | 112篇 |
2010年 | 67篇 |
2009年 | 76篇 |
2008年 | 90篇 |
2007年 | 93篇 |
2006年 | 73篇 |
2005年 | 69篇 |
2004年 | 71篇 |
2003年 | 60篇 |
2002年 | 49篇 |
2001年 | 38篇 |
2000年 | 43篇 |
1999年 | 25篇 |
1998年 | 14篇 |
1997年 | 10篇 |
1996年 | 9篇 |
1995年 | 4篇 |
1994年 | 6篇 |
1992年 | 9篇 |
1991年 | 10篇 |
1990年 | 6篇 |
1989年 | 9篇 |
1988年 | 8篇 |
1987年 | 11篇 |
1986年 | 6篇 |
1984年 | 3篇 |
1983年 | 2篇 |
1982年 | 3篇 |
1981年 | 5篇 |
1980年 | 3篇 |
1979年 | 4篇 |
1978年 | 4篇 |
1977年 | 3篇 |
1976年 | 4篇 |
1974年 | 2篇 |
1972年 | 1篇 |
1971年 | 2篇 |
1969年 | 1篇 |
1968年 | 1篇 |
排序方式: 共有1466条查询结果,搜索用时 46 毫秒
141.
Kim S Lee SH Kim JH Jeong YW Hashem MA Koo OJ Park SM Lee EG Hossein MS Kang SK Lee BC Hwang WS 《Molecular reproduction and development》2006,73(12):1523-1530
Insulin-like growth factor (IGF)-I is a receptor-mediated autocrine and/or paracrine growth and/or survival factor for mammalian embryo development. It is known to promote the growth and development of mouse preimplantation embryos. The present study was designed to investigate the effects of IGF-I (50 ng/ml), anti-IGF-I receptor antibody (50 ng/ml) and their combination on porcine preimplantation embryo development. Furthermore, the mechanism underlying the embryotropic effects of IGF-I was evaluated by monitoring the incidence of apoptosis and expression of apoptosis-related genes. In both in vitro fertilized (IVF) and somatic cell nuclear transfer (SCNT) embryos, culturing with IGF-I increased the rate of blastocyst formation and this embryotrophic effect was neutralized by culturing with IGF-I along with anti-IGF-I receptor (IGF-IR) antibody. Culturing IVF and SCNT embryos with IGF-I significantly increased the number of total cells in blastocysts and decreased the number of apoptotic nuclei. These effects of IGF-I were also neutralized by culturing with IGF-I along with anti-IGF-IR antibody. Expression of the anti-apoptotic Bcl-2 gene was increased, while expression of the pro-apoptotic Bax was decreased in both IVF and SCNT embryos cultured with IGF-I. In both IVF and SCNT embryos, anti-IGF-IR antibody along with IGF-I neutralized the effect of IGF-I on expression of Bcl-2 and Bax genes. In conclusion, the present study demonstrated that IGF-I through its specific receptors improved the developmental competence of IVF and SCNT embryos by decreasing the incidence of apoptosis and regulating apoptosis-related genes in porcine preimplantation embryos. 相似文献
142.
143.
Jin Young Chung Jung Hoon Choi Choong Hyun Lee Ki-Yeon Yoo Moo-Ho Won Dae Young Yoo Dae Won Kim Soo Young Choi Hwa Young Youn Seung Myung Moon In Koo Hwang 《Neurochemical research》2010,35(4):620-627
Microglia are main form of active immune defense, and they are constantly moving and analyzing the CNS for damaged neurons and infectious agents. In this study, we compared microglia in the spinal cord of the young adult (1–2 years old) and aged (10–12 years old) German Shepherd dogs via immunohistochemistry and western blot analysis for ionized calcium-binding adapter molecule 1 (Iba-1), a microglial marker. In addition, we also observed the interferon-γ (IFN-γ), a pro-inflammatory cytokine, and interleukin-1β (IL-1β), produced by activated microglia/macrophage, protein levels in these groups. At first, we found that neuronal nuclei (NeuN, a neuronal marker)-immunoreactive neurons were distributed throughout the grey mate of the spinal cord, and there were no significant differences between the adult and aged groups. Most of Iba-1-immunoreactive microglia were morphologically ramified microglia (resting form) in the adult group, while some Iba-1-immunoreactive microglia were morphologically activated microglia in the aged group. In western blot analysis, Iba-1, IFN-γ and IL-1β expression were increased in the aged group. This result may be associated with age-dependent changes in the spinal cord. 相似文献
144.
Jung Hoon Choi Ki-Yeon Yoo Choong Hyun Lee Ok Kyu Park Bing Chun Yan Hua Li In Koo Hwang Jeong Ho Park Sung Koo Kim Moo-Ho Won 《Neurochemical research》2010,35(10):1599-1608
In the present study, we investigated age-related differences in neuronal progenitors in the gerbil main olfactory bulb (MOB)
using doublecortin (DCX), a marker for neuronal progenitors which differentiate into neurons in the brain. No difference in
the number of neuronal nuclei (NeuN)-immunoreactive neurons was found in the MOB at variously aged gerbils. At postnatal month
(PM) 1, DCX immunoreaction was detected in all layers of the MOB except for the olfactory nerve layer. At this time point,
DCX-immunoreactive cells (neuronal progenitors) were very abundant; however, they did not have fully developed-processes.
From PM 3, the number of DCX-immunoreactive neuronal progenitors was decreased with age. At PM 6, DCX-immunoreactive cells
showed very well-developed processes. In western blot analysis, DCX protein level in the MOB was highest at PM 1. Thereafter,
levels of DCX protein were decreased with age. In the subventricular zone of the lateral ventricle, the number of Ki-67-immunoractive
cells (proliferating cells) was also significantly decreased with age. In addition, increases of α-synuclein-immunoreactive
structures were observed in the MOB with age. These results suggest that decrease in DCX-immunoreactive neuronal progenitors
and its protein levels in the MOB with age may be associated with reduction of cell proliferation in the SVZ and with an increase
in α-synuclein in the MOB. 相似文献
145.
Hae Koo Kim Delphine Luquet Erik van Oosterom Michael Dingkuhn Graeme Hammer 《Annals of botany》2010,106(1):69-78
MethodsFive sorghum hybrids, derived from inbred lines with a common genetic background and with similar phenology and plant height but contrasting tillering, were grown in five experiments. The experiments covered a wide range in radiation and temperature conditions, so that number of tillers produced varied significantly. Data on leaf area, tiller number, and biomass accumulation and partitioning were collected at regular intervals. To quantify internal plant competition for carbohydrates, a carbohydrate supply–demand index (S/Dindex) was developed and related to variation in tillering.ConclusionsThe results support the hypothesis that genotypic differences in tillering were associated with differences in plant carbon S/D balance, associated with differences in leaf size and in the threshold at which tillers grow out. The results provide avenues for phenotyping of mapping populations to identify genomic regions regulating tillering. Incorporating the results in crop growth simulation models could provide insight into the complex genotype-by-management-by-environment interactions associated with drought adaptation. 相似文献
146.
In Koo Hwang Sun Shin Yi Jae Hoon Shin Ki-Yeon Yoo Jung Hoon Choi Choong Hyun Lee Je Kyung Seong Yeo Sung Yoon Jeong Ho Park Moo-Ho Won 《Neurochemical research》2010,35(3):465-472
In the present study, we observed the effects of cyclosporine A (CsA), an efficient immunosuppressant, on cell proliferation
and neuroblast differentiation in the subgranular zone of the dentate gyrus (SZDG) in normal C57BL/6 mice using Ki67 and doublecortin
(DCX) immunohistochemical staining, respectively. At 8 weeks of age, vehicle (physiological saline) or CsA was daily administered
(40 mg/kg, i.p.) for 1 week. Animals were sacrificed at 2 weeks after last administration. CsA treatment did not show any
influences in neurons, astrocytes and microglia based on immunohistochemistry for its markers, respectively. However, in the
CsA-treated group, Fluoro-Jade B, a marker for neurodegeneration, positive cells were found in the SZDG, not in the vehicle-treated
group. In the vehicle-treated group, Ki67 immunoreactive (+) nuclei were clustered in the SZDG, whereas in the CsA-treated group Ki67+ nuclei were scattered in the SZDG, showing no difference in cell numbers. Numbers of DCX+ neuroblasts with well-developed processes (tertiary dendrites) were much lower in the CsA-treated group than those in the
vehicle-treated group; however, numbers of DCX+ neuroblasts with secondary dendrites were similar in both the groups. These results suggest that CsA significantly reduces
dendritic outgrowth and complexity from neuroblasts in the SZDG without any affecting in neurons, astrocytes and microglia
in normal mice. 相似文献
147.
Hyeong Cheol Park Chan Young Park Sung Cheol Koo Mi Sun Cheong Kyung Eun Kim Min Chul Kim Chae Oh Lim Sang Yeol Lee Dae-Jin Yun Woo Sik Chung 《Plant cell reports》2010,29(11):1297-1304
Plants express many calmodulins (CaMs) and calmodulin-like (CML) proteins that sense and transduce different Ca2+ signals. Previously, we reported divergent soybean (Glycine max) CaM isoforms (GmCaM4/5) with differential abilities to activate CaM-dependent enzymes. To elucidate biological functions
of divergent CaM proteins, we isolated a cDNA encoding a CML protein, AtCML8, from Arabidopsis. AtCML8 shows highest identity with GmCaM4 at the protein sequence level. Expression of AtCML8 was high in roots, leaves, and flowers but low in stems. In addition, the expression of AtCML8 was induced by exposure to salicylic acid or NaCl. AtCML8 showed typical characteristics of CaM such as Ca2+-dependent electrophoretic mobility shift and Ca2+ binding ability. In immunoblot analyses, AtCML8 was recognized only by antiserum against GmCaM4 but not by GmCaM1 antibodies.
Interestingly, AtCML8 was able to activate phosphodiesterase (PDE) but did not activate NAD kinase. These results suggest
that AtCML8 acts as a CML protein in Arabidopsis with characteristics similar to soybean divergent GmCaM4 at the biochemical levels. 相似文献
148.
Fluoride and zinc, alone or in combination at concentrations of 0.2 mM, inhibited production-secretion of glucosyltranferases by Streptococcus mutans UA159 growing in suspension cultures. Inhibition did not involve growth inhibition or starvation. Fluoride and zinc also inhibited glucan production, especially insoluble glucan, in fed-batch biofilms. Inhibition of biofilms appeared to be associated with starvation as indicated by markedly decreased ATP pools and iodophilic polysaccharide levels in biofilm cells. As insoluble glucans are important for virulence of mutans streptococci, the inhibitory actions of fluoride and zinc could significantly affect cariogenicity. 相似文献
149.
Anondho Wijanarko Dianursanti Misri Gozan Sang Made Krisna Andika Paramita Widiastuti Heri Hermansyah Arief Budi Witarto Kazuhiro Asami Roekmijati Widaningroem Soemantojo Kazuhisa Ohtaguchi Song Seung Koo 《Biotechnology and Bioprocess Engineering》2006,11(6):484-488
Alteration of illumination with optimum carbon dioxide fixation-based curve in this research successfully enhanced the CO2-fixation (qco2) capability ofChlorella vulgaris Buitenzorg cultivated in a bubble column photo bioreactor. The level of CO2 fixation was up to 1.91 times that observed from cultivation with intensification of illumination on an optimum growth-based curve. During 144 h of cultivation, alteration of light intensity on an optimum CO2-fixation-based curve produced a qCO2 of 6.68 h?1. Increases in light intensity based on a curve of optimum CO2-fixation produced a final cell concentration of about 5.78 g/L. Both cultivation methods were carried out under ambient pressure at a temperature of 29°C with a superficial gas velocity of 2.4 m/h (UG). Cells were grown on Beneck medium in a 1.0 L Bubble Column Photo bioreactor illuminated by aPhillips Halogen Lamp (20 W/12 V/50 Hz). The inlet gas had a carbon dioxide content of 10%. 相似文献
150.
Self-assembled monolayer (SAM) and fluorescent quantum dots (QDs) share common ground as emerging tools for nanoscale observation of biological interactions. SAMs provide excellent means of controlling the surface characteristics through individually tailored and engineered building blocks. SAMs on various surfaces have demonstrated clear advantages over uncontrolled multilayer films in fabricating electrochemical sensor, optical sensor, chemical biosensor, and atomic force microscopy. Similarly, QDs have advantages over organic fluorophores in long-term and real-time optical imaging of biological specimens. QDs conjugated with various biomolecules have been successfully applied to bioimaging, biosensing and cell encoding. 相似文献