全文获取类型
收费全文 | 113篇 |
免费 | 12篇 |
出版年
2021年 | 2篇 |
2016年 | 1篇 |
2015年 | 2篇 |
2014年 | 9篇 |
2013年 | 2篇 |
2012年 | 6篇 |
2011年 | 6篇 |
2010年 | 2篇 |
2009年 | 5篇 |
2008年 | 5篇 |
2007年 | 5篇 |
2006年 | 2篇 |
2005年 | 4篇 |
2004年 | 7篇 |
2003年 | 4篇 |
2002年 | 2篇 |
2000年 | 6篇 |
1999年 | 5篇 |
1998年 | 4篇 |
1997年 | 2篇 |
1994年 | 2篇 |
1992年 | 3篇 |
1991年 | 3篇 |
1990年 | 1篇 |
1989年 | 1篇 |
1988年 | 2篇 |
1987年 | 3篇 |
1986年 | 1篇 |
1985年 | 2篇 |
1982年 | 3篇 |
1980年 | 2篇 |
1978年 | 1篇 |
1977年 | 1篇 |
1975年 | 2篇 |
1974年 | 10篇 |
1972年 | 3篇 |
1971年 | 1篇 |
1970年 | 3篇 |
排序方式: 共有125条查询结果,搜索用时 15 毫秒
1.
V L Vaughn R Wang C Fenselau H B White 《Biochemical and biophysical research communications》1987,147(1):115-119
The tryptic phosphopeptide of hen egg white riboflavin-binding protein has been found to exist as a mixture of peptides which differ only with respect to the number of covalently bound phosphoryl groups. Anion-exchange chromatography was used to separate homologues of the tryptic phosphopeptide of egg white riboflavin-binding protein. Four peptide peaks were obtained and analyzed using plasma desorption mass spectrometry. Molecular ions obtained agree closely with calculated molecular weight values for phosphopeptides with 8, 7 and 5 phosphoryl groups. Amino acid analyses showed that the octa- and hepta-phosphorylated peptides were pure and had the same amino acid compositions. 相似文献
2.
B M Glaser P A D'Amore R G Michels A Patz A Fenselau 《The Journal of cell biology》1980,84(2):298-304
Vasoproliferative activity has been demonstrated in extracts of retinas from human, bovine, and feline sources. These retinal extracts are capable of stimulating (a) proliferation and thymidine uptake of bovine vascular endothelial cells in culture and (b) neovascularization on the chick chorioallantoic membrane. Extracts of skeletal muscle, cardiac muscle, and liver lack similar stimulatory activity. The activity is nondialyzable, stable at 56 degrees C, and inactivated at 100 degrees C. Retinal extracts stimulate the proliferation of corneal fibroblasts but have no effect on the proliferation of vascular smooth muscle cells. Indirect evidence suggests the liberation of a vasoproliferative factor from retina in several ocular disorders. The data in this report represent the first direct demonstration of vasoproliferative activity from mammalian retina. 相似文献
3.
The antitumor agent BCNU (1,3-bis(2-chloroethyl)-1-nitrosourea) was incubated with poly(C) and poly(G) in aqueous solution at 37 degrees and pH 7 to produce approximately 0.33 and 0.07% substitution, respectively. Under the same conditions, there was relatively little reaction with poly(A) and poly(U). Poylnucleotides reacted with [14C]BCNU were digested by chemical and enzymatic methods, and the derivative nucleotides were isolated by column chromatography. There were identified by a combination of ultraviolet and mass spectroscopy as 3-(beta-hydroxyethyl)CMP, 3,N4-ethano-CMP, and 7-(beta-hydroxy-ethyl)GMP. This would indicate that BCNU generates active two carbon fragments, probably chloroethyl carbonium ions, which are free to react with nucleotides. The production of these substituted bases may be important to the mechanism of action of the therapeutic nitrosoureas since they would probably alter the function of any nucleic acid which contained them. 相似文献
4.
Uxmal and Tulum are two important Mayan sites in the Yucatan peninsula. The buildings are mainly composed of limestone and grey/black discoloration is seen on exposed walls and copious greenish biofilms on inner walls. The principal microorganisms detected on interior walls at both Uxmal and Tulum were cyanobacteria; heterotrophic bacteria and filamentous fungi were also present. A dark‐pigmented mitosporic fungus and Bacillus cereus, both isolated from Uxmal, were shown to be acidogenic in laboratory cultures. Cyanobacteria belonging to rock‐degrading genera Synechocystis and Gloeocapsa were identified at both sites. Surface analysis previously showed that calcium ions were present in the biofilms on buildings at Uxmal and Tulum, suggesting the deposition of biosolubilized stone. Apart from their potential to degrade the substrate, the coccoid cyanobacteria supply organic nutrients for bacteria and fungi, which can produce organic acids, further increasing stone degradation. 相似文献
5.
Novak V Yang AC Lepicovsky L Goldberger AL Lipsitz LA Peng CK 《Biomedical engineering online》2004,3(1):39
Background
This study evaluated the effects of stroke on regulation of cerebral blood flow in response to fluctuations in systemic blood pressure (BP). The autoregulatory dynamics are difficult to assess because of the nonstationarity and nonlinearity of the component signals.Methods
We studied 15 normotensive, 20 hypertensive and 15 minor stroke subjects (48.0 ± 1.3 years). BP and blood flow velocities (BFV) from middle cerebral arteries (MCA) were measured during the Valsalva maneuver (VM) using transcranial Doppler ultrasound.Results
A new technique, multimodal pressure-flow analysis (MMPF), was implemented to analyze these short, nonstationary signals. MMPF analysis decomposes complex BP and BFV signals into multiple empirical modes, representing their instantaneous frequency-amplitude modulation. The empirical mode corresponding to the VM BP profile was used to construct the continuous phase diagram and to identify the minimum and maximum values from the residual BP (BPR) and BFV (BFVR) signals. The BP-BFV phase shift was calculated as the difference between the phase corresponding to the BPR and BFVR minimum (maximum) values. BP-BFV phase shifts were significantly different between groups. In the normotensive group, the BFVR minimum and maximum preceded the BPR minimum and maximum, respectively, leading to large positive values of BP-BFV shifts.Conclusion
In the stroke and hypertensive groups, the resulting BP-BFV phase shift was significantly smaller compared to the normotensive group. A standard autoregulation index did not differentiate the groups. The MMPF method enables evaluation of autoregulatory dynamics based on instantaneous BP-BFV phase analysis. Regulation of BP-BFV dynamics is altered with hypertension and after stroke, rendering blood flow dependent on blood pressure.6.
Jinxi Li Kevin Shefcheck John Callahan Catherine Fenselau 《Protein science : a publication of the Protein Society》2010,19(1):174-182
The Ara h 2 proteins are major determinants of peanut allergens. These proteins have not been fully studied at the molecular level. It has been previously proposed that there are two isoforms of Ara h 2, based on primary structures that were deduced from two reported cDNA sequences. In this report, four isoforms have been purified and characterized individually. Mass spectrometric methods have been used to determine the protein sequences and to define post‐translational modifications for all four isoforms. Two pairs of isoforms have been identified, corresponding to a long‐chain form and a form that is shorter by 12 amino acids. Each pair is further differentiated by the presence or absence of a two amino acid sequence at the carboxyl terminus of the protein. Modifications that were characterized include site‐specific hydroxylation of proline residues, but no glycosylation was found, in contrast to previous reports. 相似文献
7.
Danilo E Xavier Renata C Picão Raquel Girardello Lorena CC Fehlberg Ana C Gales 《BMC microbiology》2010,10(1):217
Background
Multi-drug efflux pumps have been increasingly recognized as a major component of resistance in P. aeruginosa. We have investigated the expression level of efflux systems among clinical isolates of P. aeruginosa, regardless of their antimicrobial susceptibility profile. 相似文献8.
Anna CC Aguiar Ananda C Cunha Isabela Penna Ceravolo Regina A Correia Gon?alves Arildo JB Oliveira Antoniana Ursine Krettli 《Memórias do Instituto Oswaldo Cruz》2015,110(7):906-913
Several species of Aspidosperma plants are used to treat diseases in
the tropics, including Aspidosperma ramiflorum, which acts against
leishmaniasis, an activity that is experimentally confirmed. The species, known as
guatambu-yellow, yellow peroba,
coffee-peroba andmatiambu, grows in the Atlantic
Forest of Brazil in the South to the Southeast regions. Through a guided
biofractionation of A. ramiflorum extracts, the plant activity
against Plasmodium falciparum was evaluated in vitro for toxicity
towards human hepatoma G2 cells, normal monkey kidney cells and nonimmortalised human
monocytes isolated from peripheral blood. Six of the seven extracts tested were
active at low doses (half-maximal drug inhibitory concentration < 3.8 µg/mL); the
aqueous extract was inactive. Overall, the plant extracts and the purified compounds
displayed low toxicity in vitro. A nonsoluble extract fraction and one purified
alkaloid isositsirikine (compound 5) displayed high selectivity indexes (SI) (= 56
and 113, respectively), whereas compounds 2 and 3 were toxic (SI < 10). The
structure, activity and low toxicity of isositsirikine in vitro are described here
for the first time in A. ramiflorum, but only the neutral and
precipitate plant fractions were tested for activity, which caused up to 53%
parasitaemia inhibition of Plasmodium berghei in mice with
blood-induced malaria. This plant species is likely to be useful in the further
development of an antimalarial drug, but its pharmacological evaluation is still
required. 相似文献
9.
10.
Small, Acid-Soluble Proteins as Biomarkers in Mass Spectrometry Analysis of Bacillus Spores 总被引:1,自引:0,他引:1
下载免费PDF全文
![点击此处可从《Applied microbiology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Yetrib Hathout Barbara Setlow Rosa-Martha Cabrera-Martinez Catherine Fenselau Peter Setlow 《Applied microbiology》2003,69(2):1100-1107
The use of 1 N HCl for extraction of small, acid-soluble proteins (SASP) from different Bacillus spore species was examined. The extracts were analyzed by high-performance liquid chromatography and matrix-assisted laser desorption mass spectrometry and were found to be both qualitatively and quantitatively superior to extraction by acetonitrile-5% trifluoroacetic acid (70:30, vol/vol). Both major and minor α/β- and γ-type SASP were characterized by their molecular masses or tryptic peptide maps and by searches of both protein and unannotated genome databases. For all but 1 pair (B. cereus T and B. thuringiensis subsp. Kurstaki) among the 11 variants studied the suites of SASP masses are distinctive, consistent with the use of these proteins as potential biomarkers for spore identification by mass spectrometry. 相似文献