全文获取类型
收费全文 | 185篇 |
免费 | 29篇 |
出版年
2016年 | 3篇 |
2015年 | 3篇 |
2014年 | 5篇 |
2012年 | 2篇 |
2011年 | 3篇 |
2010年 | 3篇 |
2009年 | 4篇 |
2008年 | 2篇 |
2007年 | 6篇 |
2006年 | 2篇 |
2005年 | 3篇 |
2003年 | 3篇 |
2002年 | 3篇 |
2001年 | 5篇 |
2000年 | 2篇 |
1999年 | 4篇 |
1998年 | 10篇 |
1997年 | 3篇 |
1996年 | 2篇 |
1995年 | 2篇 |
1994年 | 2篇 |
1993年 | 4篇 |
1991年 | 2篇 |
1989年 | 5篇 |
1986年 | 2篇 |
1985年 | 2篇 |
1979年 | 2篇 |
1977年 | 5篇 |
1973年 | 4篇 |
1960年 | 4篇 |
1959年 | 2篇 |
1957年 | 2篇 |
1953年 | 3篇 |
1947年 | 2篇 |
1940年 | 2篇 |
1938年 | 4篇 |
1937年 | 2篇 |
1936年 | 9篇 |
1935年 | 5篇 |
1934年 | 2篇 |
1933年 | 8篇 |
1932年 | 9篇 |
1931年 | 9篇 |
1930年 | 2篇 |
1929年 | 7篇 |
1924年 | 2篇 |
1923年 | 3篇 |
1920年 | 2篇 |
1918年 | 3篇 |
1910年 | 2篇 |
排序方式: 共有214条查询结果,搜索用时 187 毫秒
21.
Van Goor F Straley KS Cao D González J Hadida S Hazlewood A Joubran J Knapp T Makings LR Miller M Neuberger T Olson E Panchenko V Rader J Singh A Stack JH Tung R Grootenhuis PD Negulescu P 《American journal of physiology. Lung cellular and molecular physiology》2006,290(6):L1117-L1130
Cystic fibrosis (CF) is a fatal genetic disease caused by mutations in cftr, a gene encoding a PKA-regulated Cl(-) channel. The most common mutation results in a deletion of phenylalanine at position 508 (DeltaF508-CFTR) that impairs protein folding, trafficking, and channel gating in epithelial cells. In the airway, these defects alter salt and fluid transport, leading to chronic infection, inflammation, and loss of lung function. There are no drugs that specifically target mutant CFTR, and optimal treatment of CF may require repair of both the folding and gating defects. Here, we describe two classes of novel, potent small molecules identified from screening compound libraries that restore the function of DeltaF508-CFTR in both recombinant cells and cultures of human bronchial epithelia isolated from CF patients. The first class partially corrects the trafficking defect by facilitating exit from the endoplasmic reticulum and restores DeltaF508-CFTR-mediated Cl(-) transport to more than 10% of that observed in non-CF human bronchial epithelial cultures, a level expected to result in a clinical benefit in CF patients. The second class of compounds potentiates cAMP-mediated gating of DeltaF508-CFTR and achieves single-channel activity similar to wild-type CFTR. The CFTR-activating effects of the two mechanisms are additive and support the rationale of a drug discovery strategy based on rescue of the basic genetic defect responsible for CF. 相似文献
22.
Donaldson SC Straley BA Hegde NV Sawant AA DebRoy C Jayarao BM 《Applied and environmental microbiology》2006,72(6):3940-3948
Healthy calves (n = 96, 1 to 9 weeks old) from a dairy herd in central Pennsylvania were examined each month over a five-month period for fecal shedding of ceftiofur-resistant gram-negative bacteria. Ceftiofur-resistant Escherichia coli isolates (n = 122) were characterized by antimicrobial resistance (disk diffusion and MIC), serotype, pulsed-field gel electrophoresis subtypes, beta-lactamase genes, and virulence genes. Antibiotic disk diffusion assays showed that the isolates were resistant to ampicillin (100%), ceftiofur (100%), chloramphenicol (94%), florfenicol (93%), gentamicin (89%), spectinomycin (72%), tetracycline (98%), ticarcillin (99%), and ticarcillin-clavulanic acid (99%). All isolates were multidrug resistant and displayed elevated MICs. The E. coli isolates belonged to 42 serotypes, of which O8:H25 was the predominant serotype (49.2%). Pulsed-field gel electrophoresis classified the E. coli isolates into 27 profiles. Cluster analysis showed that 77 isolates (63.1%) belonged to one unique group. The prevalence of pathogenic E. coli was low (8%). A total of 117 ceftiofur-resistant E. coli isolates (96%) possessed the bla(CMY2) gene. Based on phenotypic and genotypic characterization, the ceftiofur-resistant E. coli isolates belonged to 59 clonal types. There was no significant relationship between calf age and clonal type. The findings of this study revealed that healthy dairy calves were rapidly colonized by antibiotic-resistant strains of E. coli shortly after birth. The high prevalence of multidrug-resistant nonpathogenic E. coli in calves could be a significant source of resistance genes to other bacteria that share the same environment. 相似文献
23.
24.
25.
26.
FASTEST DOCUMENTED MIGRATION OF A NORTH PACIFIC HUMPBACK WHALE 总被引:1,自引:0,他引:1
Christine M. Gabriele Janice M. Straley Louis M. Herman Richard J. Coleman 《Marine Mammal Science》1996,12(3):457-464
27.
EO Ogueji CD Nwani SC Iheanacho CE Mbah CO Okeke A Yaji 《African Journal of Aquatic Science》2018,43(3):293-303
Indiscriminate discharge of pharmaceutical waste into the aquatic ecosystem may pose serious health challenges to aquatic biota. The effect of acute exposure to ibuprofen was evaluated using changes in behaviour and haematological parameters under static bio-assay method in Clarias gariepinus. Test specimens were exposed to acute concentrations of ibuprofen (0.28, 0.33, 0.38, 0.43 and 0.48 mg l?1) for 24, 48, 72 and 96 h durations respectively. Behavioural and phenotypic changes were observed in surviving fish. There were significant (p < 0.05) concentration and duration-dependent increases in erythrocyte (RBC), haemoglobin (Hb), pack cell volume (PCV) and leukocytes (WBC) in treated fish compared to the control. Insignificant decreases (p > 0.05) in mean corpuscular volume (MCV), mean corpuscular haemoglobin (MCH) and mean corpuscular haemoglobin concentration (MCHC) were observed in treated fish compared to the control. Ibuprofen elicited dose and duration- dependent decrease in neutrophil counts with the decreases being significant (p < 0.05) in the higher doses of 0.43 and 0.48 mg l?1. Ibuprofen did not elicit any significant changes in monocytes, basophils and eosinophils. Changes observed in this study showed that ibuprofen negatively affected the health of the fish and we recommend that discharge of ibuprofen into the aquatic environment should be monitored and controlled. 相似文献
28.
Context-dependent memory: colour versus odour 总被引:2,自引:1,他引:1
An olfactory stimulus and a visual stimulus were employed in a context-
dependent memory study using a prose passage as the to-be-remembered item.
Ninety-five university students (aged 17-35 years) learned the passage of
prose in the presence of one of the stimuli and were then asked to recall
the passage with the original context either reinstated or not reinstated.
The results revealed a significant context-dependent memory effect for the
olfactory cue but not for the visual cue. They demonstrate support for the
effectiveness of odours as context cues and it is suggested that
context-dependent memory processes may underlie the formation and retrieval
of odour-evoked autobiographical memories.
相似文献
29.
30.