全文获取类型
收费全文 | 467篇 |
免费 | 31篇 |
出版年
2022年 | 3篇 |
2021年 | 9篇 |
2020年 | 3篇 |
2019年 | 7篇 |
2018年 | 6篇 |
2017年 | 4篇 |
2016年 | 9篇 |
2015年 | 7篇 |
2014年 | 15篇 |
2013年 | 21篇 |
2012年 | 28篇 |
2011年 | 27篇 |
2010年 | 12篇 |
2009年 | 7篇 |
2008年 | 21篇 |
2007年 | 27篇 |
2006年 | 24篇 |
2005年 | 12篇 |
2004年 | 12篇 |
2003年 | 21篇 |
2002年 | 23篇 |
2001年 | 7篇 |
2000年 | 17篇 |
1999年 | 16篇 |
1998年 | 4篇 |
1996年 | 4篇 |
1995年 | 5篇 |
1992年 | 11篇 |
1991年 | 12篇 |
1990年 | 8篇 |
1989年 | 14篇 |
1988年 | 7篇 |
1987年 | 5篇 |
1986年 | 9篇 |
1985年 | 4篇 |
1984年 | 5篇 |
1982年 | 7篇 |
1979年 | 3篇 |
1977年 | 6篇 |
1976年 | 2篇 |
1975年 | 6篇 |
1974年 | 6篇 |
1973年 | 6篇 |
1972年 | 4篇 |
1971年 | 4篇 |
1970年 | 4篇 |
1969年 | 4篇 |
1968年 | 2篇 |
1967年 | 5篇 |
1966年 | 3篇 |
排序方式: 共有498条查询结果,搜索用时 781 毫秒
61.
Waki T Shimokawa J Watanabe S Yoshinaga T Ogawa K 《Journal of invertebrate pathology》2012,111(1):50-55
Manila clams, Ruditapes philippinarum, are widely harvested in the coastal waters in Japan. However, there have been significant decreases in the populations of Manila clams since the 1980s. It is thought that infection with the protozoan Perkinsus species has contributed to these decreases. A previous study demonstrated that high infection levels of a pure strain of Perkinsus olseni (ATCC PRA-181) were lethal to hatchery-raised small Manila clams, however, the pathogenicity of wild strain Perkinsus species to wild Manila clam is unclear. To address this, we challenged large (30-40mm in shell length) and small (3-15mm in shell length) wild Manila clams with Perkinsus species isolated from naturally infected wild Manila clams. We report high mortalities among the small clams, but not among the large ones. This is the first report to confirm the pathogenicity of wild isolate of Perkinsus species to wild Manila clams. 相似文献
62.
Borowsky AD Bandhuvula P Kumar A Yoshinaga Y Nefedov M Fong LG Zhang M Baridon B Dillard L de Jong P Young SG West DB Saba JD 《Journal of lipid research》2012,53(9):1920-1931
Sphingosine-1-phosphate (S1P) is a bioactive sphingolipid involved in immunity, inflammation, angiogenesis, and cancer. S1P lyase (SPL) is the essential enzyme responsible for S1P degradation. SPL augments apoptosis and is down-regulated in cancer. SPL generates a S1P chemical gradient that promotes lymphocyte trafficking and as such is being targeted to treat autoimmune diseases. Despite growing interest in SPL as a disease marker, antioncogene, and pharmacological target, no comprehensive characterization of SPL expression in mammalian tissues has been reported. We investigated SPL expression in developing and adult mouse tissues by generating and characterizing a β-galactosidase-SPL reporter mouse combined with immunohistochemistry, immunoblotting, and enzyme assays. SPL was expressed in thymic and splenic stromal cells, splenocytes, Peyer's Patches, colonic lymphoid aggregates, circulating T and B lymphocytes, granulocytes, and monocytes, with lowest expression in thymocytes. SPL was highly expressed within the CNS, including arachnoid lining cells, spinal cord, choroid plexus, trigeminal nerve ganglion, and specific neurons of the olfactory bulb, cerebral cortex, midbrain, hindbrain, and cerebellum. Expression was detected in brown adipose tissue, female gonads, adrenal cortex, bladder epithelium, Harderian and preputial glands, and hair follicles. This unique expression pattern suggests SPL has many undiscovered physiological functions apart from its role in immunity. 相似文献
63.
Masaru?TanakaEmail author Yasuhiro?Takahata Rie?Kurata Hiroki?Nakayama Masaru?Yoshinaga 《Molecular breeding : new strategies in plant improvement》2012,29(3):565-574
To elucidate further the genetic mechanism underlying anthocyanin accumulation in the storage roots of recent Japanese purple-fleshed
sweetpotato cultivars, we compared the structure of the IbMYB1 gene in cultivar Ayamurasaki and its spontaneous mutant, AYM96, whose storage roots do not accumulate anthocyanin. Amplification
of the IbMYB1 genomic fragment covering the coding sequences suggested that the genome of Ayamurasaki contained three types of IbMYB1 sequences, named IbMYB1-1, IbMYB1-2a and IbMYB1-2b, whereas AYM96 had only IbMYB1-1. Although these three IbMYB1 sequences had identical coding sequences, IbMYB1-1 had a 7-bp insertion in the first intron. IbMYB1-2a and IbMYB1-2b were characterized by a single nucleotide polymorphism in the second intron. Further cloning and sequencing of the flanking
regions of these IbMYB1 sequences showed that the promoter and 3′ flanking regions of IbMYB1-2a and IbMYB1-2b were different from those of IbMYB1-1. Genetic analysis using an F1 population derived from a cross between the purple-fleshed cultivar Murasakimasari and AYM96 suggested that IbMYB1-2 sequences are responsible for anthocyanin accumulation in the storage roots. The structural features of these three IbMYB1 sequences and identification of the IbMYB1-2null sequence, which contained sequences very similar to those of the flanking regions of IbMYB1-2a and IbMYB1-2b, but which lacked the sequence around the coding region, suggested that IbMYB1 genes in recent Japanese purple-fleshed cultivars had been established through multiple gene-duplication events. 相似文献
64.
65.
Cui YM Yasutomi E Otani Y Yoshinaga T Ido K Sawada K Ohwada T 《Bioorganic & medicinal chemistry letters》2008,18(19):5197-5200
We found that the podocarpic acid structure provides a new scaffold for chemical modulators of large-conductance calcium-activated K(+) channels (BK channels). Structure-activity analysis indicates the importance of both the arrangement (i.e., location and orientation) of the carboxylic acid functionality of ring A and the hydrophobic region of ring C for expression of BK channel-opening activity. 相似文献
66.
67.
Different roles of bases within the integration signal sequence of human immunodeficiency virus type 1 in vitro. 总被引:3,自引:3,他引:0
下载免费PDF全文
![点击此处可从《Journal of virology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
To investigate the roles of bases near the tips of each strand of the long terminal repeat of the human immunodeficiency virus type 1 in the integration reaction, we examined the efficiencies of both binding and integration activities of staggered-ended substrates and mismatched mutant substrates by the integration assay and the UV cross-linking assay. Our results suggest that some bases of the human immunodeficiency virus type 1 long terminal repeat are required primarily for binding, whereas others are more critical for later reaction steps in vitro. 相似文献
68.
Nathan D. Mathewson Orr Ashenberg Itay Tirosh Simon Gritsch Elizabeth M. Perez Sascha Marx Livnat Jerby-Arnon Rony Chanoch-Myers Toshiro Hara Alyssa R. Richman Yoshinaga Ito Jason Pyrdol Mirco Friedrich Kathrin Schumann Michael J. Poitras Prafulla C. Gokhale L. Nicolas Gonzalez Castro Marni E. Shore Kai W. Wucherpfennig 《Cell》2021,184(5):1281-1298.e26
- Download : Download high-res image (226KB)
- Download : Download full-size image
69.
Helga E. Hildebrandt-Stark George J. Marcus Koji Yoshinaga Harold R. Behrman Roy O. Greep 《Prostaglandins & other lipid mediators》1975,9(2):231-244
Adult female guinea pigs were actively immunized with prostaglandin F2α conjugated to bovine serum albumin (BSA). Control animals, immunized against BSA continued to cycle normally, while the animals immunized against prostaglandin F2α stopped cycling after one to three normal cycles. Laparotomy at 30 days after the last estrus revealed no recently formed corpora lutea. During the remaining 70 days of observation the antibody titer increased to 1:700, accompanied by increasing total serum estrogens (136 pg/ml at day 100) and a slow decline in circulating progesterone levels (0.6 ng/ml at day 100). The ovaries at day 100 contained degenerated corpora lutea and luteinized follicles. The suppression of the estrous cycle in the present experiments was interpreted as resulting from prolongation of luteal function as well as from inhibition of ovulation. 相似文献
70.
Naoki Tokuhara Kana Namiki Mai Uesugi Chihiro Miyamoto Makoto Ohgoh Katsutoshi Ido Takashi Yoshinaga Toshihiko Yamauchi Junro Kuromitsu Sadao Kimura Norimasa Miyamoto Yoshitoshi Kasuya 《The Journal of biological chemistry》2010,285(43):33294-33306
One of the family of voltage-gated calcium channels (VGCC), the N-type Ca2+ channel, is located predominantly in neurons and is associated with a variety of neuronal responses, including neurodegeneration. A precise mechanism for how the N-type Ca2+ channel plays a role in neurodegenerative disease, however, is unknown. In this study, we immunized N-type Ca2+ channel α1B-deficient (α1B−/−) mice and their wild type (WT) littermates with myelin oligodendrocyte glycoprotein 35–55 and analyzed the progression of experimental autoimmune encephalomyelitis (EAE). The neurological symptoms of EAE in the α1B−/− mice were less severe than in the WT mice. In conjunction with these results, sections of the spinal cord (SC) from α1B−/− mice revealed a reduction in both leukocytic infiltration and demyelination compared with WT mice. No differences were observed in the delayed-type hypersensitivity response, spleen cell proliferation, or cytokine production from splenocytes between the two genotypes. On the other hand, Western blot array analysis and RT-PCR revealed that a typical increase in the expression of MCP-1 in the SC showed a good correlation with the infiltration of leukocytes into the SC. Likewise, immunohistochemical analysis showed that the predominant source of MCP-1 was activated microglia. The cytokine-induced production of MCP-1 in primary cultured microglia from WT mice was significantly higher than that from α1B−/− mice and was significantly inhibited by a selective N-type Ca2+ channel antagonist, ω-conotoxin GVIA or a withdrawal of extracellular Ca2+. These results suggest that the N-type Ca2+ channel is involved in the pathogenesis of EAE at least in part by regulating MCP-1 production by microglia. 相似文献