全文获取类型
收费全文 | 731篇 |
免费 | 50篇 |
学科分类
生物科学 | 781篇 |
出版年
2023年 | 7篇 |
2022年 | 7篇 |
2021年 | 15篇 |
2020年 | 9篇 |
2019年 | 12篇 |
2018年 | 16篇 |
2017年 | 14篇 |
2016年 | 29篇 |
2015年 | 46篇 |
2014年 | 38篇 |
2013年 | 49篇 |
2012年 | 55篇 |
2011年 | 51篇 |
2010年 | 27篇 |
2009年 | 33篇 |
2008年 | 45篇 |
2007年 | 48篇 |
2006年 | 40篇 |
2005年 | 43篇 |
2004年 | 43篇 |
2003年 | 33篇 |
2002年 | 22篇 |
2001年 | 9篇 |
2000年 | 8篇 |
1999年 | 8篇 |
1998年 | 6篇 |
1997年 | 2篇 |
1996年 | 4篇 |
1995年 | 2篇 |
1994年 | 6篇 |
1993年 | 8篇 |
1992年 | 3篇 |
1991年 | 6篇 |
1990年 | 4篇 |
1989年 | 1篇 |
1988年 | 6篇 |
1987年 | 3篇 |
1986年 | 5篇 |
1985年 | 6篇 |
1983年 | 3篇 |
1982年 | 2篇 |
1978年 | 1篇 |
1976年 | 1篇 |
1975年 | 2篇 |
1967年 | 1篇 |
1966年 | 2篇 |
排序方式: 共有781条查询结果,搜索用时 46 毫秒
21.
22.
Chihiro Handa Tadahiro Okubo Aogu Yoneyama Masashi Nakamura Mari Sakaguchi Narumi Takahashi Mayumi Okamoto Ayumi Tanaka-Oda Tanaka Kenzo Tomoaki Ichie Takao Itioka 《Journal of plant research》2013,126(1):73-79
Macaranga myrmecophytes (ant-plants) provide their partner symbiotic ants (plant-ants) with food bodies as their main food, and they are protected by the plant-ants from herbivores. The amount of resource allocated to food bodies determines the plant-ant colony size and consequently determines the intensity of ant defense (anti-herbivore defense by plant-ants). As constraints in resource allocation change as plants grow, the plant-ant colony size is hypothesized to change with the ontogenesis of Macaranga myrmecophyte. To determine the ontogenetic change in the relative size of the plant-ant colony, we measured the dry weights of the whole plant-ant colony and all of the aboveground parts of trees at various ontogenetic stages for a myrmecophytic species (Macaranga beccariana) in a Bornean lowland tropical rain forest. Ant biomass increased as plant biomass increased. However, the rate of increase gradually declined, and the ant biomass appeared to reach a ceiling once trees began to branch. The ant/plant biomass ratio consistently decreased as plant biomass increased, with the rate of decrease gradually accelerating. We infer that the ontogenetic reduction in ant/plant biomass ratio is caused by an ontogenetic change in resource allocation to food rewards for ants related to the physiological changes accompanying the beginning of branching. 相似文献
23.
Yoshiko Onda Rimei Nishimura Aya Morimoto Hironari Sano Kazunori Utsunomiya Naoko Tajima The Diabetes Epidemiology Research International Mortality Study Group 《PloS one》2016,11(3)
Objective
To follow up Japanese patients with type 1 diabetes for a maximum of 40 years to examine when they transitioned from pediatric care to adult care and to explore whether the attending physician, i.e., pediatrician or internist, was associated with prognosis.Methods
Participants consisted of 1,299 patients who had been diagnosed as having type 1 diabetes at less than 15 years old between 1965 and 1979 identified through two nationwide surveys. Patients were classified as having received either pediatric care or adult care at the age of 15 and 30, and were compared for differences in mortality associated with the attending physician.Results
The attending physicians were confirmed for a total of 1,093 patients at the age of 15. Of these patients, 43.8% and 40.3% received pediatric care and adult care, respectively. Of the 569 patients receiving pediatric care, 74.2%, 56.6%, 53.4%, and 51.3% continued with pediatric care at 20, 30, 40, and 50 years old, respectively. The attending physicians (pediatrician or internist) at the age of 15 and 30 had no significant impact on their survival (P = 0. 892, 0.411, respectively).Conclusions
More than half of the patients who had received pediatric care at the age of 15 continued to receive pediatric care even after the age of 30, suggesting that their transition was far from smooth, while the attending physician at the age of both 15 and 30 was not a prognostic factor for mortality. Thus, the timing for transition to adult care in these patients has no relationship with mortality in Japan. 相似文献24.
Phylogeography of Arabis serrata (Brassicaceae) in the Japanese Archipelago based on chloroplast DNA variations 下载免费PDF全文
Arabis serrata (Brassicaceae), a perennial plant widely distributed along the Japanese Archipelago, occurs in various habitats: for example, limestone zones, serpentine barrens, volcanic soils, and roadsides. It likely survived by adapting to its surrounding environment, resulting in great morphological and ecological variation. In this study, we performed a phylogeographic analysis to examine past changes in the distribution of A. serrata following climate oscillations during the Pleistocene. To cover most of A. serrata's range, leaves were collected from eight to ten individuals randomly selected from each of 37 populations in the Japanese Archipelago. Two chloroplast noncoding regions of the samples were amplified and sequenced: trnT(GGU)‐psbD and trnH(GUG)‐psbA spacers. Twenty‐five haplotypes were detected and distinguished by 31 substitutions. Four main haplotypes were observed in many populations distributed throughout the Japanese Archipelago. According to the genetic boundaries detected using the Monmonier algorithm, A. serrata is clustered into four groups, each including several populations: Hokkaido Island, northern mainland Honshu, central Japan, and western Japan. The boundaries, however, were not robust because all genetic parameters did not support the differentiation among groups. These results indicate the absence of an obvious geographic structure in the distribution of A. serrata, suggesting that this species has experienced a rapid range expansion in postglacial times. 相似文献
25.
Practical selection methods for rat and mouse round spermatids without DNA staining by flow cytometric cell sorting 下载免费PDF全文
26.
Yu Kitadate David J. Jörg Moe Tokue Ayumi Maruyama Rie Ichikawa Soken Tsuchiya Eri Segi-Nishida Toshinori Nakagawa Aya Uchida Chiharu Kimura-Yoshida Seiya Mizuno Fumihiro Sugiyama Takuya Azami Masatsugu Ema Chiyo Noda Satoru Kobayashi Isao Matsuo Yoshiakira Kanai Shosei Yoshida 《Cell Stem Cell》2019,24(1):79-92.e6
27.
28.
Takano Y Yamauchi K Hayakawa K Hiramatsu N Kasai A Okamura M Yokouchi M Shitamura A Yao J Kitamura M 《FEBS letters》2007,581(3):421-426
Expression of nephrin, a crucial component of the glomerular slit diaphragm, is downregulated in patients with proteinuric glomerular diseases. Using conditionally immortalized reporter podocytes, we found that bystander macrophages as well as macrophage-derived cytokines IL-1beta and TNF-alpha markedly suppressed activity of the nephrin gene promoter in podocytes. The cytokine-initiated repression was reversible, observed on both basal and inducible expression, independent of Wilms' tumor suppressor WT1, and caused in part via activation of the phosphatidylinositol-3-kinase/Akt pathway. These results indicated a novel mechanism by which activated macrophages participate in the induction of proteinuria in glomerular diseases. 相似文献
29.
Rapid, transient induction of ER stress in the liver and kidney after acute exposure to heavy metal: evidence from transgenic sensor mice 总被引:2,自引:0,他引:2
Hiramatsu N Kasai A Du S Takeda M Hayakawa K Okamura M Yao J Kitamura M 《FEBS letters》2007,581(10):2055-2059
Endoplasmic reticulum (ER) stress-responsive alkaline phosphatase (ES-TRAP) serves as a sensitive indicator for ER stress. In response to heavy metals including cadmium, nickel and cobalt, hepatocytes and renal tubular cells expressing ES-TRAP exhibited ER stress and decreased ES-TRAP activity. In ES-TRAP transgenic mice, acute exposure to cadmium showed rapid, transient decreases in the activity of serum ES-TRAP. It was inversely correlated with the induction of endogenous ER stress markers in the liver and kidney. Our result provides first evidence for the acute, reversible induction of ER stress in vivo after exposure to heavy metal. 相似文献
30.
The tiger pufferfish (fugu), Takifugu rubripes, is a model fish that has had its genome entirely sequenced. By performing genomewide linkage analyses, we show that the sex of fugu is determined by a single chromosomal region on linkage group 19 in an XX-XY system. 相似文献