全文获取类型
收费全文 | 1007篇 |
免费 | 70篇 |
国内免费 | 1篇 |
专业分类
1078篇 |
出版年
2023年 | 12篇 |
2022年 | 24篇 |
2021年 | 29篇 |
2020年 | 20篇 |
2019年 | 16篇 |
2018年 | 26篇 |
2017年 | 22篇 |
2016年 | 30篇 |
2015年 | 44篇 |
2014年 | 56篇 |
2013年 | 80篇 |
2012年 | 77篇 |
2011年 | 66篇 |
2010年 | 53篇 |
2009年 | 48篇 |
2008年 | 71篇 |
2007年 | 56篇 |
2006年 | 51篇 |
2005年 | 39篇 |
2004年 | 51篇 |
2003年 | 36篇 |
2002年 | 27篇 |
2001年 | 14篇 |
2000年 | 19篇 |
1999年 | 10篇 |
1998年 | 8篇 |
1997年 | 4篇 |
1996年 | 5篇 |
1995年 | 4篇 |
1994年 | 2篇 |
1993年 | 4篇 |
1992年 | 5篇 |
1991年 | 4篇 |
1990年 | 8篇 |
1989年 | 4篇 |
1988年 | 10篇 |
1987年 | 4篇 |
1986年 | 5篇 |
1985年 | 4篇 |
1984年 | 2篇 |
1983年 | 4篇 |
1982年 | 2篇 |
1979年 | 6篇 |
1978年 | 2篇 |
1976年 | 3篇 |
1975年 | 2篇 |
1974年 | 4篇 |
1972年 | 1篇 |
1969年 | 2篇 |
1967年 | 1篇 |
排序方式: 共有1078条查询结果,搜索用时 15 毫秒
991.
Watanabe J Mitani Y Kawai Y Kikuchi T Kogo Y Oguchi-Katayama A Kanamori H Usui K Itoh M Cizdziel PE Lezhava A Tatsumi K Ichikawa Y Togo S Shimada H Hayashizaki Y 《BioTechniques》2007,43(4):479-484
A key feature of the smart amplification process version 2 (SMAP-2) is the ability to suppress mismatch amplification by using a unique asymmetric primer design and Thermus aquaticus MutS (Taq MutS). However we report here that use of SMAP-2 for polymorphism determination of the UGT1A1 *28 allele required a further ancillary approach for complete background suppression. The UGT1A1 *28 allele is a microsatellite copy number polymorphism. This is the first reported SMAP-2 assay designed for genotyping genetic variations of microsatellites. We found that by the addition of a primer to the amplification reaction, called a competitive probe (CP), assay specificity could be significantly enhanced. Including sample preparation time and use of a CP-enhanced SMAP-2 assay, we could rapidly detect the UGT1A1 *28 polymorphism within 60 min. To test our method, we compared results from PCR sequencing and the CP-enhanced SMAP-2 assay on 116 human blood samples for UGT1A1 *28 polymorphism and demonstrated perfect concordance. These results illustrate the versatility of SMAP-2 for molecular diagnostics and provide a new approach for enhancing SMAP-2 assay specificity. 相似文献
992.
Multiple mating can be costly, but also beneficial for females. When the costs outweigh the benefits, mated females can be reluctant to remate for some time. Conversely, females will be likely to remate when they need to replenish sperm and/or receive nutrients contained in the accessory ejaculate substances. Water striders have been commonly used in mating studies as many show a vigorous struggle between the sexes. Generally, water strider females frequently mate with many males and lay many eggs during mating period. However, little is known about their oviposition and refractory periods after an initial mating event. In this study, we revealed that single-mated females of the small water strider, Microvelia horvathi, could lay eggs for 40 days, reflecting approximately half of their potential oviposition periods. It suggested that M. horvathi females do not need to mate to replenish sperm for some time once they mate. Our results also showed that no female remated after 1 or 3 days of an initial mating event. The proportion of female remating increased with time after the initial mating, however, remating levels reached 26.7% even after 14 days. In this sense, any significant cost of mating outweighs the benefit, which might be one of the factors lowering their remating levels. 相似文献
993.
Hiroyuki Morino Ryosuke Miyamoto Shizuo Ohnishi Hirofumi Maruyama Hideshi Kawakami 《BMC neurology》2014,14(1):1-5
Background
Genetic modifiers are important clues for the identification of therapeutic targets in neurodegenerative diseases. Huntington disease (HD) is one of the most common autosomal dominant inherited neurodegenerative diseases. The clinical symptoms include motor abnormalities, cognitive decline and behavioral disturbances. Symptom onset is typically between 40 and 50 years of age, but can vary by several decades in extreme cases and this is in part determined by modifying genetic factors. The metabolic master regulator PGC-1α, coded by the PPARGC1A gene, coordinates cellular respiration and was shown to play a role in neurodegenerative diseases, including HD.Methods
Using a candidate gene approach we analyzed a large European cohort (n?=?1706) from the REGISTRY study for associations between PPARGC1A genotype and age at onset (AO) in HD.Results
We report that a coding variant (rs3736265) in PPARGC1A is associated with an earlier motor AO in men but not women carrying the HD mutation.Conclusions
These results further strengthen the evidence for a role of PGC-1α in HD and unexpectedly suggest a gender effect. 相似文献994.
Koji Takayama Yohei Kawakami Makoto Kobayashi Nick Greco James H Cummins Takehiko Matsushita Ryosuke Kuroda Masahiro Kurosaka Freddie H Fu Johnny Huard 《Arthritis research & therapy》2014,16(6)
Introduction
Recent studies have revealed that rapamycin activates autophagy in human chondrocytes preventing the development of osteoarthritis (OA) like changes in vitro, while the systemic injection of rapamycin reduces the severity of experimental osteoarthritis in a murine model of OA in vivo. Since the systemic use of rapamycin is associated with numerous side effects, the goal of the current study was to examine the beneficial effect of local intra-articular injection of rapamycin in a murine model of OA and to elucidate the mechanism of action of rapamycin on articular cartilage.Methods
Destabilization of the medial meniscus (DMM) was performed on 10-week-old male mice to induce OA. Intra-articular injections of 10 μl of rapamycin (10 μM) were administered twice weekly for 8 weeks. Articular cartilage damage was analyzed by histology using a semi-quantitative scoring system at 8 and 12 weeks after surgery. Mammalian target of rapamycin (mTOR), light chain 3 (LC3), vascular endothelial growth factor (VEGF), collagen, type X alpha 1 (COL10A1), and matrix metallopeptidase 13 (MMP13) expressions were analyzed by immunohistochemistry. VEGF, COL10A1, and MMP13 expressions were further examined via quantitative RT-PCR (qPCR).Results
Intra-articular injection of rapamycin significantly reduced the severity of articular cartilage degradation at 8 and 12 weeks after DMM surgery. A reduction in mTOR expression and the activation of LC3 (an autophagy marker) in the chondrocytes was observed in the rapamycin treated mice. Rapamycin treatment also reduced VEGF, COL10A1, and MMP13 expressions at 8 and 12 weeks after DMM surgery.Conclusion
These results demonstrate that the intra-articular injection of rapamycin could reduce mTOR expression, leading to a delay in articular cartilage degradation in our OA murine model. Our observations suggest that local intra-articular injection of rapamycin could represent a potential therapeutic approach to prevent OA. 相似文献995.
Yoko Oka Haruko Tashiro Ryosuke Sirasaki Tadashi Yamamoto Nobu Akiyama Kazuo Kawasugi 《Nucleosides, nucleotides & nucleic acids》2014,33(4-6):434-438
In order to elucidate the mechanism of hyperuricemia in hematologic malignancies, we have retrospectively investigated the uric acid metabolism in 418 chemotherapy-naïve patients with hematologic malignancies. Hyperuricemia was present in 116 (27.8%) of these patients on initial hospitalization. Among 65 hyperuricemic patients analyzed uric acid metabolism, six (9.2%) had overproduction type, 52 (80.0%) had underexcretion type, and seven (10.8%) had a mixed type. Fourteen patients (3.3%) developed tumor lysis syndrome in 418 patients. 相似文献
996.
Yusuke Miyazaki Atsunobu Murase Masato Shiina Kenichi Naoe Ryosuke Nakashiro Junichi Honda Junichiro Yamaide Hiroshi Senou 《Biodiversity and Conservation》2014,23(9):2383-2391
The Internet has changed the way biologists communicate; this includes the collection of information on fish biology. This technological change may allow the possibility for biological monitoring by general citizens via the Internet. The Japanese Internet atlas of fishes, WEB sakana-zukan, has been in operation since 2002. It provides an opportunity to communicate and accumulate information on fish biology by amateur users, who consist mainly of sports fishing fans. This website has functioned not only as an entertainment and educational tool for users with an environmental and ichthyological interest. To date, more than 35,000 photographs of fishes have been registered on the website by more than 1,000 unique users, and more than 37,500 photographs of fishes have been posted in its bulletin board system (linking approximately 28,000 photographs to the website) by more than 2,000 unique users. As these photographs almost always include time and locality data, it is possible to provide distribution data by publishing the information as scientific papers or registering them as collections at the Kanagawa Prefectural Museum of Natural History (the Image Database of Fishes (KPM-NR) contributing to the Global Biodiversity Information Facility). If the communication method is developed and improved, various scientists will be able to collect much more biodiversity data from general citizens via the Internet. 相似文献
997.
Tomoko Yamazaki Mayumi Mori Satoko Arai Ryosuke Tateishi Masanori Abe Mihoko Ban Akemi Nishijima Maki Maeda Takeharu Asano Toshihiro Kai Kiyohiro Izumino Jun Takahashi Kayo Aoyama Sei Harada Toru Takebayashi Toshiaki Gunji Shin Ohnishi Shinji Seto Yukio Yoshida Yoichi Hiasa Kazuhiko Koike Ken-ichi Yamamura Ken-ichiro Inoue Toru Miyazaki 《PloS one》2014,9(10)
Background
Hepatocellular carcinoma (HCC), the fifth most common cancer type and the third highest cause of cancer death worldwide, develops in different types of liver injuries, and is mostly associated with cirrhosis. However, non-alcoholic fatty liver disease often causes HCC with less fibrosis, and the number of patients with this disease is rapidly increasing. The high mortality rate and the pathological complexity of liver diseases and HCC require blood biomarkers that accurately reflect the state of liver damage and presence of HCC.Methods and Findings
Here we demonstrate that a circulating protein, apoptosis inhibitor of macrophage (AIM) may meet this requirement. A large-scale analysis of healthy individuals across a wide age range revealed a mean blood AIM of 4.99±1.8 µg/ml in men and 6.06±2.1 µg/ml in women. AIM levels were significantly augmented in the younger generation (20s–40s), particularly in women. Interestingly, AIM levels were markedly higher in patients with advanced liver damage, regardless of disease type, and correlated significantly with multiple parameters representing liver function. In mice, AIM levels increased in response to carbon tetrachloride, confirming that the high AIM observed in humans is the result of liver damage. In addition, carbon tetrachloride caused comparable states of liver damage in AIM-deficient and wild-type mice, indicating no influence of AIM levels on liver injury progression. Intriguingly, certain combinations of AIM indexes normalized to liver marker score significantly distinguished HCC patients from non-HCC patients and thus could be applicable for HCC diagnosis.Conclusion
AIM potently reveals both liver damage and HCC. Thus, our results may provide the basis for novel diagnostic strategies for this widespread and fatal disease. 相似文献998.
Natural variation in the genes responsible for maturity loci E1, E2, E3 and E4 in soybean 总被引:1,自引:0,他引:1
Yasutaka Tsubokura Satoshi Watanabe Zhengjun Xia Hiroyuki Kanamori Harumi Yamagata Akito Kaga Yuichi Katayose Jun Abe Masao Ishimoto Kyuya Harada 《Annals of botany》2014,113(3):429-441
Background and Aims
The timing of flowering has a direct impact on successful seed production in plants. Flowering of soybean (Glycine max) is controlled by several E loci, and previous studies identified the genes responsible for the flowering loci E1, E2, E3 and E4. However, natural variation in these genes has not been fully elucidated. The aims of this study were the identification of new alleles, establishment of allele diagnoses, examination of allelic combinations for adaptability, and analysis of the integrated effect of these loci on flowering.Methods
The sequences of these genes and their flanking regions were determined for 39 accessions by primer walking. Systematic discrimination among alleles was performed using DNA markers. Genotypes at the E1–E4 loci were determined for 63 accessions covering several ecological types using DNA markers and sequencing, and flowering times of these accessions at three sowing times were recorded.Key Results
A new allele with an insertion of a long interspersed nuclear element (LINE) at the promoter of the E1 locus (e1-re) was identified. Insertion and deletion of 36 bases in the eighth intron (E2-in and E2-dl) were observed at the E2 locus. Systematic discrimination among the alleles at the E1–E3 loci was achieved using PCR-based markers. Allelic combinations at the E1–E4 loci were found to be associated with ecological types, and about 62–66 % of variation of flowering time could be attributed to these loci.Conclusions
The study advances understanding of the combined roles of the E1–E4 loci in flowering and geographic adaptation, and suggests the existence of unidentified genes for flowering in soybean, 相似文献999.
Heba S. Said Wataru Suda Shigeki Nakagome Hiroshi Chinen Kenshiro Oshima Sangwan Kim Ryosuke Kimura Atsushi Iraha Hajime Ishida Jiro Fujita Shuhei Mano Hidetoshi Morita Taeko Dohi Hiroki Oota Masahira Hattori 《DNA research》2014,21(1):15-25
Analysis of microbiota in various biological and environmental samples under a variety of conditions has recently become more practical due to remarkable advances in next-generation sequencing. Changes leading to specific biological states including some of the more complex diseases can now be characterized with relative ease. It is known that gut microbiota is involved in the pathogenesis of inflammatory bowel disease (IBD), mainly Crohn''s disease and ulcerative colitis, exhibiting symptoms in the gastrointestinal tract. Recent studies also showed increased frequency of oral manifestations among IBD patients, indicating aberrations in the oral microbiota. Based on these observations, we analyzed the composition of salivary microbiota of 35 IBD patients by 454 pyrosequencing of the bacterial 16S rRNA gene and compared it with that of 24 healthy controls (HCs). The results showed that Bacteroidetes was significantly increased with a concurrent decrease in Proteobacteria in the salivary microbiota of IBD patients. The dominant genera, Streptococcus, Prevotella, Neisseria, Haemophilus, Veillonella, and Gemella, were found to largely contribute to dysbiosis (dysbacteriosis) observed in the salivary microbiota of IBD patients. Analysis of immunological biomarkers in the saliva of IBD patients showed elevated levels of many inflammatory cytokines and immunoglobulin A, and a lower lysozyme level. A strong correlation was shown between lysozyme and IL-1β levels and the relative abundance of Streptococcus, Prevotella, Haemophilus and Veillonella. Our data demonstrate that dysbiosis of salivary microbiota is associated with inflammatory responses in IBD patients, suggesting that it is possibly linked to dysbiosis of their gut microbiota. 相似文献
1000.
Patricia T. Honna Renata Fuganti-Pagliarini Leonardo C. Ferreira Mayla D. C. Molinari Silvana R. R. Marin Maria C. N. de Oliveira José R. B. Farias Norman Neumaier Liliane M. Mertz-Henning Norihito Kanamori Kazuo Nakashima Hironori Takasaki Kaoru Urano Kazuo Shinozaki Kazuko Yamaguchi-Shinozaki Janete A. Desidério Alexandre L. Nepomuceno 《Molecular breeding : new strategies in plant improvement》2016,36(11):157