全文获取类型
收费全文 | 123篇 |
免费 | 12篇 |
出版年
2022年 | 1篇 |
2020年 | 1篇 |
2019年 | 2篇 |
2018年 | 2篇 |
2017年 | 1篇 |
2016年 | 1篇 |
2015年 | 6篇 |
2014年 | 9篇 |
2013年 | 8篇 |
2012年 | 6篇 |
2011年 | 2篇 |
2010年 | 3篇 |
2009年 | 5篇 |
2007年 | 9篇 |
2006年 | 3篇 |
2005年 | 6篇 |
2004年 | 5篇 |
2003年 | 5篇 |
2002年 | 2篇 |
2001年 | 3篇 |
1999年 | 5篇 |
1998年 | 2篇 |
1997年 | 5篇 |
1996年 | 1篇 |
1995年 | 2篇 |
1993年 | 1篇 |
1992年 | 4篇 |
1990年 | 3篇 |
1989年 | 2篇 |
1988年 | 3篇 |
1987年 | 3篇 |
1986年 | 2篇 |
1985年 | 4篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1982年 | 2篇 |
1979年 | 1篇 |
1978年 | 4篇 |
1977年 | 3篇 |
1974年 | 1篇 |
1973年 | 1篇 |
1972年 | 1篇 |
1959年 | 1篇 |
1953年 | 1篇 |
1874年 | 1篇 |
排序方式: 共有135条查询结果,搜索用时 15 毫秒
101.
102.
103.
J R Scocca K O Hartog S S Krag 《Biochemical and biophysical research communications》1988,156(3):1063-1069
Restriction digests of genomic DNA from tunicamycin-resistant Chinese hamster ovary cells, 3E11, were probed with the yeast transferase gene, ALG7. The data presented suggest moderate amplification of the N-acetylglucosaminyl-1-phosphate transferase gene occurred in these cells, consistent with the previously observed chromosomal translocations and increased enzymatic activity. This is the first example of gene amplification as a mechanism for aberrations in N-linked glycosylation. 相似文献
104.
Abdullah Alghasham Abdulaziz AM Al Salloom Ahmed SS Alghamadi 《Nucleosides, nucleotides & nucleic acids》2015,34(1):56-68
Present study probes the role of peroxynitrite (ONOO-)-modified thymidine-5′-monophosphate (TMP) in SLE patients with different disease activity scores according to the SLE Disease Activity Index (SLEDAI). Serum analysis showed significant increased number of subjects positive for anti-ONOO--TMP-protein antibodies in SLE patients with different SLEDAI scores. Interestingly, the levels of these antibodies were significantly higher among SLE patients, whose SLEDAI scores were ≥20. In addition, a significant correlation was observed between the levels of anti-ONOO--TMP-protein antibodies and the SLEDAI score (r = 0.595, p < 0.0001). In short, this study shows a positive association between anti-ONOO--TMP-protein antibodies and SLEDAI. The stronger response observed in patients with higher SLEDAI scores suggests that anti-ONOO--TMP-protein antibodies may be useful in evaluating the progression of SLE and in elucidating the mechanisms of disease pathogenesis. 相似文献
105.
Fernanda Fraga Campos Policarpo A Sales Junior Alvaro José Romanha Márcio SS Araújo Ezequias P Siqueira Jarbas M Resende Tania MA Alves Olindo A Martins-Filho Vera Lúcia dos Santos Carlos A Rosa Carlos L Zani Betania Barros Cota 《Memórias do Instituto Oswaldo Cruz》2015,110(1):65-74
Aiming to identify new sources of bioactive secondary metabolites, we isolated 82
endophytic fungi from stems and barks of the native Brazilian tree Caesalpinia
echinata Lam. (Fabaceae). We tested their ethyl acetate extracts in several in vitro
assays. The organic extracts from three isolates showed antibacterial activity
against Staphylococcus aureus and Escherichia coli [minimal inhibitory concentration
(MIC) 32-64 μg/mL]. One isolate inhibited the growth of Salmonella typhimurium (MIC
64 μg/mL) and two isolates inhibited the growth of Klebsiella oxytoca (MIC 64 μg/mL),
Candida albicans and Candida tropicalis (MIC 64-128 μg/mL). Fourteen extracts at a
concentration of 20 μg/mL showed antitumour activities against human breast cancer
and human renal cancer cells, while two isolates showed anti-tumour activities
against human melanoma cancer cells. Six extracts were able to reduce the
proliferation of human peripheral blood mononuclear cells, indicating some degree of
selective toxicity. Four isolates were able to inhibit Leishmania (Leishmania)
amazonensis and one isolate inhibited Trypanosoma cruzi by at least 40% at 20 μg/mL.
The trypanocidal extract obtained from Fusarium sp. [] culture was subjected
to bioguided fractionation, which revealed beauvericin as the compound responsible
for the observed toxicity of Fusarium sp. to T. cruzi. This depsipeptide showed a
half maximal inhibitory concentration of 1.9 μg/mL (2.43 μM) in a T. cruzi cellular
culture assay. KF611679相似文献
106.
EG Ciolac SS Mantuani CM Neiva CEL Verardi DM Pess?a-Filho L Pimenta 《Biology of sport / Institute of Sport》2015,32(2):103-108
The aim of the present study was to analyse the usefulness of the 6-20 rating of perceived exertion (RPE) scale for prescribing and self-regulating high-intensity interval training (HIT) in young individuals. Eight healthy young subjects (age = 27.5±6.7 years) performed maximal graded exercise testing to determine their maximal and reserve heart rate (HR). Subjects then performed two HIT sessions (20 min on a treadmill) prescribed and regulated by their HR (HR: 1 min at 50% alternated with 1 min at 85% of reserve HR) or RPE (RPE: 1 minute at the 9-11 level [very light-fairly light] alternated with 1 minute at the 15-17 level [hard-very hard]) in random order. HR response and walking/running speed during the 20 min of exercise were compared between sessions. No significant difference between sessions was observed in HR during low- (HR: 135±15 bpm; RPE: 138±20 bpm) and high-intensity intervals (HR: 168±15 bpm; RPE: 170±18 bpm). Walking/running speed during low- (HR: 5.7±1.2 km · h−1; RPE: 5.7±1.3 km · h−1) and high-intensity intervals (HR: 7.8±1.9 km · h−1; RPE: 8.2±1.7 km · h−1) was also not different between sessions. No significant differences were observed in HR response and walking/running speed between HIT sessions prescribed and regulated by HR or RPE. This finding suggests that the 6-20 RPE scale may be a useful tool for prescribing and self-regulating HIT in young subjects. 相似文献
107.
Changes in pH are now widely accepted as a signalling mechanism in cells. In plants, proton pumps in the plasma membrane and tonoplast play a key role in regulation of intracellular pH homeostasis and maintenance of transmembrane proton gradients. Proton transport in response to external stimuli can be expected to be finely regulated spatially and temporally. With the ambition to follow such changes live, a new genetically encoded sensor, pHusion, has been developed. pHusion is especially designed for apoplastic pH measurements. It was constitutively expressed in Arabidopsis and targeted for expression in either the cytosol or the apoplast including intracellular compartments. pHusion consists of the tandem concatenation of enhanced green fluorescent protein (EGFP) and monomeric red fluorescent protein (mRFP1), and works as a ratiometric pH sensor. Live microscopy at high spatial and temporal resolution is highly dependent on appropriate immobilization of the specimen for microscopy. Medical adhesive often used in such experiments destroys cell viability in roots. Here a novel system for immobilizing Arabidopsis seedling roots for perfusion experiments is presented which does not impair cell viability. With appropriate immobilization, it was possible to follow changes of the apoplastic and cytosolic pH in mesophyll and root tissue. Rapid pH homeostasis upon external pH changes was reflected by negligible cytosolic pH fluctuations, while the apoplastic pH changed drastically. The great potential for analysing pH regulation in a whole-tissue, physiological context is demonstrated by the immediate alkalinization of the subepidermal apoplast upon external indole-3-acetic acid administration. This change is highly significant in the elongation zone compared with the root hair zone and control roots. 相似文献
108.
Helene M Langevin Donna M Rizzo James R Fox Gary J Badger Junru Wu Elisa E Konofagou Debbie Stevens-Tuttle Nicole A Bouffard Martin H Krag 《BMC systems biology》2007,1(1):25-12
Background
In humans, connective tissue forms a complex, interconnected network throughout the body that may have mechanosensory, regulatory and signaling functions. Understanding these potentially important phenomena requires non-invasive measurements of collagen network structure that can be performed in live animals or humans. The goal of this study was to show that ultrasound can be used to quantify dynamic changes in local connective tissue structure in vivo. We first performed combined ultrasound and histology examinations of the same tissue in two subjects undergoing surgery: in one subject, we examined the relationship of ultrasound to histological images in three dimensions; in the other, we examined the effect of a localized tissue perturbation using a previously developed robotic acupuncture needling technique. In ten additional non-surgical subjects, we quantified changes in tissue spatial organization over time during needle rotation vs. no rotation using ultrasound and semi-variogram analyses. 相似文献109.
110.
The enzyme activity of Mg-ATPase, Na+ -K+ -ATPase, 5'-nucleotidase and NAD(P)H-oxidase was cytochemically detected at the ultrastructural level in mouse peritoneal macrophages infected with untreated and with specific antibody-coated Toxoplasma gondii tachyzoites. The Mg++ -ATPase and 5'-nucleotidase were distributed throughout the macrophages'plasma membrane but were not observed in the membrane lining endocytic vacuoles containing ingested parasites; however, Na+ -K+ -ATPase activity was detected in the macrophages'plasma membrane as well as in the parasitophorous vacuoles that contained untreated or specific antibody-coated parasites. Reaction product, indicative of NAD(P)H-oxidase, was detected in the parasitophorous vacuoles that contained only-specific antibody-coated parasites. 相似文献