全文获取类型
收费全文 | 481篇 |
免费 | 35篇 |
出版年
2021年 | 2篇 |
2018年 | 4篇 |
2017年 | 2篇 |
2016年 | 8篇 |
2015年 | 16篇 |
2014年 | 20篇 |
2013年 | 25篇 |
2012年 | 18篇 |
2011年 | 26篇 |
2010年 | 26篇 |
2009年 | 27篇 |
2008年 | 25篇 |
2007年 | 26篇 |
2006年 | 15篇 |
2005年 | 21篇 |
2004年 | 16篇 |
2003年 | 10篇 |
2002年 | 11篇 |
2001年 | 12篇 |
2000年 | 15篇 |
1999年 | 7篇 |
1998年 | 14篇 |
1997年 | 14篇 |
1996年 | 9篇 |
1995年 | 10篇 |
1994年 | 4篇 |
1993年 | 11篇 |
1992年 | 3篇 |
1991年 | 7篇 |
1990年 | 3篇 |
1989年 | 4篇 |
1988年 | 10篇 |
1985年 | 5篇 |
1984年 | 7篇 |
1983年 | 5篇 |
1982年 | 17篇 |
1981年 | 6篇 |
1980年 | 2篇 |
1979年 | 6篇 |
1978年 | 5篇 |
1977年 | 6篇 |
1976年 | 5篇 |
1975年 | 7篇 |
1974年 | 4篇 |
1973年 | 3篇 |
1972年 | 4篇 |
1971年 | 2篇 |
1968年 | 2篇 |
1967年 | 1篇 |
1964年 | 1篇 |
排序方式: 共有516条查询结果,搜索用时 15 毫秒
11.
12.
13.
14.
From 180 gray squirrels (Sciurus c. carolinesis), 942 isolates of fungi representing 19 genera were recovered upon culture of hair-skin scrapings and toenails. Of the isolates, 170 represented known human pathogens and 142, squirrel pathogens. A human infection of Trichophyton mentagrophytes was derived from handling the squirrels. Skin lesions of seven squirrels were attributable to T. mentagrophytes and Mucor sp. 相似文献
15.
The signal produced by fluorescence in situ hybridization (FISH) often is inconsistent among cells and sensitivity is low. Small DNA targets on the chromatin are difficult to detect. We report here an improved nick translation procedure for Texas red and Alexa Fluor 488 direct labeling of FISH probes. Brighter probes can be obtained by adding excess DNA polymerase I. Using such probes, a 30?kb yeast transgene, and the rp1, rp3 and zein multigene clusters were clearly detected. 相似文献
16.
Christopher I Keeling Macaire MS Yuen Nancy Y Liao T Roderick Docking Simon K Chan Greg A Taylor Diana L Palmquist Shaun D Jackman Anh Nguyen Maria Li Hannah Henderson Jasmine K Janes Yongjun Zhao Pawan Pandoh Richard Moore Felix AH Sperling Dezene P W Huber Inanc Birol Steven JM Jones Joerg Bohlmann 《Genome biology》2013,14(3):R27
17.
The molecular integrity of the active site of phytases from fungi is critical for maintaining phytase function as efficient catalytic
machines. In this study, the molecular dynamics (MD) of two monomers of phytase B from Aspergillus niger, the disulfide intact
monomer (NAP) and a monomer with broken disulfide bonds (RAP), were simulated to explore the conformational basis of the
loss of catalytic activity when disulfide bonds are broken. The simulations indicated that the overall secondary and tertiary
structures of the two monomers were nearly identical but differed in some crucial secondary–structural elements in the vicinity of
the disulfide bonds and catalytic site. Disulfide bonds stabilize the β-sheet that contains residue Arg66 of the active site and
destabilize the α-helix that contains the catalytic residue Asp319. This stabilization and destabilization lead to changes in the shape
of the active–site pocket. Functionally important hydrogen bonds and atomic fluctuations in the catalytic pocket change during the
RAP simulation. None of the disulfide bonds are in or near the catalytic pocket but are most likely essential for maintaining the
native conformation of the catalytic site.
Abbreviations
PhyB - 2.5 pH acid phophatese from Aspergillus niger, NAP - disulphide intact monomer of Phytase B, RAP - disulphide reduced monomer of Phytase B, Rg - radius of gyration, RMSD - root mean square deviation, MD - molecular dynamics. 相似文献18.
KB Cullberg T Christiansen SK Paulsen JM Bruun SB Pedersen B Richelsen 《Obesity (Silver Spring, Md.)》2013,21(3):454-460
Background:
Vascular growth is a prerequisite for adipose tissue (AT) development and expansion. Some AT cytokines and hormones have effects on vascular development, like vascular endothelial growth factor (VEGF‐A), angiopoietin (ANG‐1), ANG‐2 and angiopoietin‐like protein‐4 (ANGPTL‐4).Methods:
In this study, the independent and combined effects of diet‐induced weight loss and exercise on AT gene expression and proteins levels of those angiogenic factors were investigated. Seventy‐nine obese males and females were randomized to: 1. Exercise‐only (EXO; 12‐weeks exercise without diet‐restriction), 2. Hypocaloric diet (DIO; 8‐weeks very low energy diet (VLED) + 4‐weeks weight maintenance diet) and 3. Hypocaloric diet and exercise (DEX; 8‐weeks VLED + 4‐weeks weight maintenance diet combined with exercise throughout the 12 weeks). Blood samples and fat biopsies were taken before and after the intervention.Results:
Weight loss was 3.5 kg in the EXO group and 12.3 kg in the DIO and DEX groups. VEGF‐A protein was non‐significantly reduced in the weight loss groups. ANG‐1 protein levels were significantly reduced 22‐25% after all three interventions (P < 0.01). The ANG‐1/ANG‐2 ratio was also decreased in all three groups (P < 0.05) by 27‐38%. ANGPTL‐4 was increased in the EXO group (15%, P < 0.05) and 9% (P < 0.05) in the DIO group. VEGF‐A, ANG‐1, and ANGPTL‐4 were all expressed in human AT, but only ANGPTL‐4 was influenced by the interventions.Conclusions:
Our data show that serum VEGF‐A, ANG‐1, ANG‐2, and ANGPTL‐4 levels are influenced by weight changes, indicating the involvement of these factors in the obese state. Moreover, it was found that weight loss generally was associated with a reduced angiogenic activity in the circulation. 相似文献19.
20.
Orr SJ Morgan NM Buick RJ Boyd CR Elliott J Burrows JF Jefferies CA Crocker PR Johnston JA 《The Journal of biological chemistry》2007,282(6):3418-3422
CD33-related Siglecs (sialic acid-binding immunoglobulin-like lectins) 5-11 are inhibitory receptors that contain a membrane proximal ITIM (immunoreceptor tyrosine-based inhibitory motif) (I/V/L/)XYXX(L/V), which can recruit SHP-1/2. However, little is known about the regulation of these receptors. SOCS3 (suppressor of cytokine signaling 3) is up-regulated during inflammation and competes with SHP-1/2 for binding to ITIM-like motifs on various cytokine receptors resulting in inhibition of signaling. We show that SOCS3 binds the phosphorylated ITIM of Siglec 7 and targets it for proteasomal-mediated degradation, suggesting that Siglec 7 is a novel SOCS target. Following ligation, the ECS E3 ligase is recruited by SOCS3 to target Siglec 7 for proteasomal degradation, and SOCS3 expression is decreased concomitantly. In addition, we found that SOCS3 expression blocks Siglec 7-mediated inhibition of cytokine-induced proliferation. This is the first time that a SOCS target has been reported to degrade simultaneously with the SOCS protein and that inhibitory receptors have been shown to be degraded in this way. This may be a mechanism by which the inflammatory response is potentiated during infection. 相似文献