全文获取类型
收费全文 | 2309篇 |
免费 | 138篇 |
出版年
2023年 | 8篇 |
2022年 | 21篇 |
2021年 | 28篇 |
2020年 | 20篇 |
2019年 | 33篇 |
2018年 | 40篇 |
2017年 | 24篇 |
2016年 | 56篇 |
2015年 | 74篇 |
2014年 | 104篇 |
2013年 | 126篇 |
2012年 | 149篇 |
2011年 | 141篇 |
2010年 | 74篇 |
2009年 | 62篇 |
2008年 | 107篇 |
2007年 | 132篇 |
2006年 | 110篇 |
2005年 | 108篇 |
2004年 | 97篇 |
2003年 | 104篇 |
2002年 | 93篇 |
2001年 | 53篇 |
2000年 | 70篇 |
1999年 | 48篇 |
1998年 | 21篇 |
1997年 | 13篇 |
1996年 | 20篇 |
1995年 | 19篇 |
1993年 | 7篇 |
1992年 | 46篇 |
1991年 | 42篇 |
1990年 | 45篇 |
1989年 | 44篇 |
1988年 | 42篇 |
1987年 | 29篇 |
1986年 | 22篇 |
1985年 | 20篇 |
1984年 | 21篇 |
1983年 | 18篇 |
1982年 | 18篇 |
1981年 | 16篇 |
1980年 | 13篇 |
1979年 | 13篇 |
1974年 | 8篇 |
1971年 | 8篇 |
1969年 | 9篇 |
1968年 | 10篇 |
1967年 | 6篇 |
1966年 | 8篇 |
排序方式: 共有2447条查询结果,搜索用时 375 毫秒
91.
Mohamed Omar Yosuke Matsuo Hajime Maeda Yoshinori Saito Takashi Tanaka 《Phytochemistry letters》2013,6(3):486-490
Two novel glycosides, 4,5-dimethoxy-3-hydroxyphenol 1-O-β-(6′-O-galloyl)-glucopyranoside (1) and (+)-2α-O-galloyl lyoniresinol 3α-O-β-d-xylopyranoside (2), as well as a novel ellagitannin named epiquisqualin B (3), were isolated from sapwood of Quercus mongolica var. crispula along with 19 known phenolic compounds. The structures of the novel compounds were elucidated on the basis of chemical and spectroscopic investigation. Compound 2 is the first example of a lignan galloyl ester, and 3 is the oxidation product of vescalagin, which is the major ellagitannin of this plant. 相似文献
92.
Shigeaki Matsuda Hirotaka Hiyoshi Sarunporn Tandhavanant Toshio Kodama 《Microbiology and immunology》2020,64(3):167-181
Vibrio parahaemolyticus is a leading cause of seafood-borne bacterial gastroenteritis in humans. Since its discovery in 1950, this bacterium has been isolated in widespread outbreaks and in sporadic cases of gastroenteritis worldwide. Although the exotoxin, thermostable direct hemolysin, had been the focus of extensive research on the pathogenicity of V. parahaemolyticus, the whole-genome sequencing of a clinical isolate, RIMD2210633 strain, was a breakthrough in this field. The possession of two sets of gene clusters for type III secretion systems (T3SS1 and T3SS2) was unveiled by that genome project. T3SS is a protein export apparatus that delivers bacterial proteins, called effectors, directly into the host's cytosol, to disrupt host cell function. The subsequent studies have established that T3SS2, which is encoded in an 80 kb pathogenicity island called V. parahaemolyticus pathogenicity island (Vp-PAI), is closely related to enteropathogenicity. Recent functional analyses of Vp-PAI-encoded genes revealed the sophisticated mechanisms in V. parahaemolyticus for sensing the intestinal environment and host cell contact, and a dozen T3SS2-exported proteins encoded in Vp-PAI. In this review, we summarize recent advances in V. parahaemolyticus research regarding the control of the expression of Vp-PAI-encoded genes, structural components and the secretory regulation of T3SS2, and the biological activities of T3SS2-exported effectors. Thus, Vp-PAI-encoded T3SS2 becomes an important key in the postgenomic era to shed light on the enteropathogenic mechanism of V. parahaemolyticus. 相似文献
93.
Nishiyama Misa Nakamichi Noritaka Yoshimura Tomoyuki Masuo Yusuke Komori Tomoe Ishimoto Takahiro Matsuo Jun-ichi Kato Yukio 《Neurochemical research》2020,45(11):2664-2678
Neurochemical Research - Understanding of the underlying mechanism of epilepsy is desired since some patients fail to control their seizures. The carnitine/organic cation transporter OCTN1/SLC22A4... 相似文献
94.
95.
Tomoko Lee Yasuhiro Takeshima Yo Okizuka Kiyoshi Hamahira Noriko Kusunoki Hiroyuki Awano Mariko Yagi Norio Sakai Masafumi Matsuo Kazumoto Iijima 《Gene》2013
Geleophysic dysplasia (GD) is a rare disorder characterized by severe short stature, short hands and feet, limited joint mobility, skin thickening, characteristic facial features (e.g., a “happy” face), and cardiac valvular disorders that often result in an early death. The genes ADAMTSL2 (a disintegrin-like and metalloprotease with thrombospondin type 1 motif-like 2) and FBN1 (fibrillin 1) were recently identified as causative genes for GD. Here, we describe a 10-year-old Japanese female with GD who was born to non-consanguineous parents. At the age of 11 months, she was referred to our hospital because of very short stature for her age (− 4.4 standard deviations of the age-matched value) and a “happy” face with full cheeks, a shortened nose, hypertelorism, and a long and flat philtrum, characteristic of GD. Her hands and feet were small, her skin was thickened, and her joint mobility was generally limited. She had cardiac valvular disorders and history of recurrent respiratory failure. Mutation analysis revealed no abnormalities in ADAMTSL2. However, analysis of FBN1 revealed a novel heterozygous mutation (c.5161T > T/G) in exon 41, which encodes transforming growth factor-β-binding protein-like domain 5 (TB5). GD is an extremely rare disorder and, to our knowledge, only one case of GD with an FBN1 mutation has been reported in Japan. Similar to the previously reported cases of GD, the mutation in the current patient was located in the TB5 domain, which suggests that abnormalities in this domain of FBN1 are responsible for GD. 相似文献
96.
Keisuke Toyoda Kunihiko Tanaka Shinsuke Nakagawa Dinh Ha Duy Thuy Kenta Ujifuku Kensaku Kamada Kentaro Hayashi Takayuki Matsuo Izumi Nagata Masami Niwa 《Cellular and molecular neurobiology》2013,33(4):489-501
Glioblastoma multiforme (GBM) cells invade along the existing normal capillaries in brain. Normal capillary endothelial cells function as the blood–brain barrier (BBB) that limits permeability of chemicals into the brain. To investigate whether GBM cells modulate the BBB function of normal endothelial cells, we developed a new in vitro BBB model with primary cultures of rat brain endothelial cells (RBECs), pericytes, and astrocytes. Cells were plated on a membrane with 8 μm pores, either as a monolayer or as a BBB model with triple layer culture. The BBB model consisted of RBEC on the luminal side as a bottom, and pericytes and astrocytes on the abluminal side as a top of the chamber. Human GBM cell line, LN-18 cells, or lung cancer cell line, NCI-H1299 cells, placed on either the RBEC monolayer or the BBB model increased the transendothelial electrical resistance (TEER) values against the model, which peaked within 72 h after the tumor cell application. The TEER value gradually returned to baseline with LN-18 cells, whereas the value quickly dropped to the baseline in 24 h with NCI-H1299 cells. NCI-H1299 cells invaded into the RBEC layer through the membrane, but LN-18 cells did not. Fibroblast growth factor 2 (FGF-2) strengthens the endothelial cell BBB function by increased occludin and ZO-1 expression. In our model, LN-18 and NCI-H1299 cells secreted FGF-2, and a neutralization antibody to FGF-2 inhibited LN-18 cells enhanced BBB function. These results suggest that FGF-2 would be a novel therapeutic target for GBM in the perivascular invasive front. 相似文献
97.
Masako Nomaguchi Masaru Yokoyama Ken Kono Emi E. Nakayama Tatsuo Shioda Naoya Doi Sachi Fujiwara Akatsuki Saito Hirofumi Akari Kei Miyakawa Akihide Ryo Hirotaka Ode Yasumasa Iwatani Tomoyuki Miura Tatsuhiko Igarashi Hironori Sato Akio Adachi 《Journal of virology》2013,87(21):11447-11461
Human immunodeficiency virus type 1 (HIV-1) replication in macaque cells is restricted mainly by antiviral cellular APOBEC3, TRIM5α/TRIM5CypA, and tetherin proteins. For basic and clinical HIV-1/AIDS studies, efforts to construct macaque-tropic HIV-1 (HIV-1mt) have been made by us and others. Although rhesus macaques are commonly and successfully used as infection models, no HIV-1 derivatives suitable for in vivo rhesus research are available to date. In this study, to obtain novel HIV-1mt clones that are resistant to major restriction factors, we altered Gag and Vpu of our best HIV-1mt clone described previously. First, by sequence- and structure-guided mutagenesis, three amino acid residues in Gag-capsid (CA) (M94L/R98S/G114Q) were found to be responsible for viral growth enhancement in a macaque cell line. Results of in vitro TRIM5α susceptibility testing of HIV-1mt carrying these substitutions correlated well with the increased viral replication potential in macaque peripheral blood mononuclear cells (PBMCs) with different TRIM5 alleles, suggesting that the three amino acids in HIV-1mt CA are involved in the interaction with TRIM5α. Second, we replaced the transmembrane domain of Vpu of this clone with the corresponding region of simian immunodeficiency virus SIVgsn166 Vpu. The resultant clone, MN4/LSDQgtu, was able to antagonize macaque but not human tetherin, and its Vpu effectively functioned during viral replication in a macaque cell line. Notably, MN4/LSDQgtu grew comparably to SIVmac239 and much better than any of our other HIV-1mt clones in rhesus macaque PBMCs. In sum, MN4/LSDQgtu is the first HIV-1 derivative that exhibits resistance to the major restriction factors in rhesus macaque cells. 相似文献
98.
Stefan Harjes William C. Solomon Ming Li Kuan-Ming Chen Elena Harjes Reuben S. Harris Hiroshi Matsuo 《Journal of virology》2013,87(12):7008-7014
APOBEC3G has an important role in human defense against retroviral pathogens, including HIV-1. Its single-stranded DNA cytosine deaminase activity, located in its C-terminal domain (A3Gctd), can mutate viral cDNA and restrict infectivity. We used time-resolved nuclear magnetic resonance (NMR) spectroscopy to determine kinetic parameters of A3Gctd''s deamination reactions within a 5′-CCC hot spot sequence. A3Gctd exhibited a 45-fold preference for 5′-CCC substrate over 5′-CCU substrate, which explains why A3G displays almost no processivity within a 5′-CCC motif. In addition, A3Gctd''s shortest substrate sequence was found to be a pentanucleotide containing 5′-CCC flanked on both sides by a single nucleotide. A3Gctd as well as full-length A3G showed peak deamination velocities at pH 5.5. We found that H216 is responsible for this pH dependence, suggesting that protonation of H216 could play a key role in substrate binding. Protonation of H216 appeared important for HIV-1 restriction activity as well, since substitutions of H216 resulted in lower restriction in vivo. 相似文献
99.
Shin-ichi Ikeda Yoshifumi Tamura Saori Kakehi Kageumi Takeno Minako Kawaguchi Takahiro Watanabe Fumihiko Sato Takeshi Ogihara Akio Kanazawa Yoshio Fujitani Ryuzo Kawamori Hirotaka Watada 《Biochemical and biophysical research communications》2013
Exercise enhances insulin sensitivity in skeletal muscle, but the underlying mechanism remains obscure. Recent data suggest that alternatively activated M2 macrophages enhance insulin sensitivity in insulin target organs such as adipose tissue and liver. Therefore, the aim of this study was to determine the role of anti-inflammatory M2 macrophages in exercise-induced enhancement of insulin sensitivity in skeletal muscle. C57BL6J mice underwent a single bout of treadmill running (20 m/min, 90 min). Twenty-four hours later, ex vivo insulin-stimulated 2-deoxy glucose uptake was found to be increased in plantaris muscle. This change was associated with increased number of CD163-expressing macrophages (i.e. M2-polarized macrophages) in skeletal muscle. Systemic depletion of macrophages by pretreatment of mice with clodronate-containing liposome abrogated both CD163-positive macrophage accumulation in skeletal muscle as well as the enhancement of insulin sensitivity after exercise, without affecting insulin-induced phosphorylation of Akt and AS160 or exercise-induced GLUT4 expression. These results suggest that accumulation of M2-polarized macrophages is involved in exercise-induced enhancement of insulin sensitivity in mouse skeletal muscle, independently of the phosphorylation of Akt and AS160 and expression of GLUT4. 相似文献
100.