全文获取类型
收费全文 | 127篇 |
免费 | 9篇 |
专业分类
136篇 |
出版年
2021年 | 2篇 |
2018年 | 1篇 |
2017年 | 2篇 |
2016年 | 2篇 |
2015年 | 7篇 |
2014年 | 5篇 |
2013年 | 3篇 |
2012年 | 2篇 |
2011年 | 5篇 |
2010年 | 4篇 |
2009年 | 2篇 |
2008年 | 2篇 |
2007年 | 4篇 |
2006年 | 4篇 |
2005年 | 3篇 |
2004年 | 4篇 |
2003年 | 2篇 |
2002年 | 4篇 |
2001年 | 1篇 |
2000年 | 1篇 |
1999年 | 1篇 |
1998年 | 1篇 |
1997年 | 4篇 |
1993年 | 2篇 |
1992年 | 4篇 |
1991年 | 2篇 |
1990年 | 6篇 |
1989年 | 3篇 |
1988年 | 3篇 |
1987年 | 4篇 |
1986年 | 6篇 |
1985年 | 9篇 |
1984年 | 2篇 |
1983年 | 1篇 |
1982年 | 2篇 |
1981年 | 4篇 |
1980年 | 2篇 |
1979年 | 3篇 |
1978年 | 3篇 |
1977年 | 2篇 |
1976年 | 1篇 |
1975年 | 3篇 |
1974年 | 5篇 |
1973年 | 1篇 |
1970年 | 2篇 |
排序方式: 共有136条查询结果,搜索用时 15 毫秒
11.
Erwin Bay Xosé Luís Deán‐Ben Genny A. Pang Alexandre Douplik Daniel Razansky 《Journal of biophotonics》2015,8(1-2):102-111
Lack of sensory feedback during laser surgery prevents surgeons from discerning the exact location of the incision, which increases duration and complexity of the treatment. In this study we demonstrate a new method for monitoring of laser ablation procedures. Real‐time tracking of the exact three dimensional (3D) lesion profile is accomplished by detection of shock waves emanating from the ablation spot and subsequent reconstruction of the incision location using time‐of‐flight data obtained from multiple acoustic detectors. Here, incisions of up to 9 mm in depth, created by pulsed laser ablation of fresh bovine tissue samples, were successfully monitored in real time. It was further observed that, by utilizing as little as 12 detection elements, the incision profile can be characterized with accuracy below 0.5 mm in all three dimensions and in good agreement with histological examinations. The proposed method holds therefore promise for delivering high precision real‐time feedback during laser surgeries. (© 2013 WILEY‐VCH Verlag GmbH &Co. KGaA, Weinheim) 相似文献
12.
Rodríguez-Vivas RI Quiñones-Avila FJ Ramírez-Cruz GT Cruz D Wagner G 《Revista de biología tropical》2007,55(1):127-133
Isolation of a field strain of Babesia bigemina (Piroplasma: Babesiidae) and establishment of in vitro culture for antigen production. Bovine b abesiosis, caused by Babesia bigemina, is a barrier for livestock development; it results in high economic loss to Mexican livestock. Control requires adequate antigens for diagnosis and vaccination programs. However, because of antigenic variation among Babesia strains, it is necessary to use antigens prepared from local strains. The purpose of the present study was to isolate a local field strain and to establish the in vitro culture of B. bigemina by the evaluation of the constituent's concentration of culture media. Thirty engorged female Boophilus microplus were collected from cattle suffering clinical babesiosis (B. bigemina) in Yucatan state, Mexico. These ticks were sent to the laboratory for detection of Babesia sp. vermicules. Eggs were kept at 83-85 % humidity and 27 degrees C until hatching. Larvae were transferred to an esplenectomized calf (B-1). The resulting nymphs were transferred to an esplenectomized calf (B-2). Twelve days later, B. bigemina (local strain) was detected in calf B-2 and its infected blood was frozen in liquid nitrogen to initiate the in vitro culture. The Microaerophilus Stationary Phase (MASP) in vitro culture method was used to reactivate the parasite. Three different concentrations of culture media (70, 60 and 50%), serum (30, 40 and 50%) and uninfected red blood cells (5, 10 and 15 %) were used in order to know the convenient concentrations to obtain the highest percentage of infected red blood cells (PEI). The cultured strain was used to prepare antigens for the Immunofluorescence Antibody Test (IFAT) and several concentrations of serum and conjugate were tested. Strain isolation was successful; 30 days were needed to obtain a PEI of 1.5%. The isolated strain was frozen in liquid nitrogen and the parasites were reactivated with the in vitro culture MASP method. The concentration of culture media that produced the highest PEI (14%) (p < 0.05) was 30% serum, 70% M199 and 5%. Uninfected Red Blood cells antigens were successfully used in the IFAT and the best dilutions to differentiate between positive and negative controls were serum 1:80 and conjugate 1:80. The isolated B. bigemina local strain requires particular conditions of in vitro culture by the MASP method to reach high numbers of infected red blood cells, needed to prepare and provide high quality antigens for serological diagnosis of B. bigemina. 相似文献
13.
T Bellini F Dallocchio D Degani S Spisani R Gavioli S Traniello 《Biochemical and biophysical research communications》1986,141(2):524-527
Myelin basic protein, one of the major membrane protein component of the central nervous system, was used to probe the molecular mechanism of cellular activation. Pre-treatment of human neutrophils with myelin basic protein selectively inhibits the formyl-peptide-induced chemotaxis, without affecting chemotaxis evoked by casein and activated serum. Furthermore, both the degranulation and superoxide anion production stimulated by the chemotactic peptide are not modified by the prior treatment of the neutrophils with myelin basic protein. 相似文献
14.
D Degani T Bellini C M Bergamini M Matteuzzi F Dallocchio 《Biochemistry international》1989,19(4):687-693
Preincubation with 1 nM 17 beta-estradiol changes the partition behaviour of human erythrocytes in dextran-poly(ethylene glycol) aqueous phases. Erythrocyte partition decreases reaching a minimum after 5 min of incubation, then slowly increases returning to starting values after 30 min. The effect is specifically induced by the isomer of estradiol, whereas the alpha isomer and other steroid hormones (progesterone, testosterone and 5 alpha-dihydrotestosterone) are uneffective. The effect of the hormone can be suppressed by treatment of erythrocytes with either N-ethyl maleimide, sodium vanadate, or ouabain, or carrying out incubations in potassium-free buffer. These data suggest that the effect of estradiol on phase partition of erythrocytes is mediated by the (Na,K)-ATPase. 相似文献
15.
The reaction of X-537A (XH) with Co2+ in methanol to form the complex CoX+ has been studied fluorometrically to determine the equilibrium constant as a function of temperature. The effect of complexation on the proton NMR spectrum of the X-537A was studied to determine the kinetics of complex formation. Comparing the data for the reaction XM+→X? + M2+ in methanol at 25° for several M2+ we find that the equilibrium constants increase in the order CoX+ < MnX+ < NiX+ and span only a factor of 5 while the rate constants increase in the order NiX+ < CoX+ < MnX+ and span a factor of more than 100. 相似文献
16.
Host Physiology and Pathogenic Variation of Cochliobolus heterostrophus Strains with Mutations in the G Protein Alpha Subunit, CGA1 下载免费PDF全文
Ofir Degani Rudy Maor Ruthi Hadar Amir Sharon Benjamin A. Horwitz 《Applied microbiology》2004,70(8):5005-5009
Conserved eukaryotic signaling proteins participate in development and disease in plant-pathogenic fungi. Strains with mutations in CGA1, a heterotrimeric G protein G alpha subunit gene of the maize pathogen Cochliobolus heterostrophus, are defective in several developmental pathways. Conidia from CGA1 mutants germinate as abnormal, straight-growing germ tubes that form few appressoria, and the mutants are female sterile. Nevertheless, these mutants can cause normal lesions on plants, unlike other filamentous fungal plant pathogens in which functional homologues of CGA1 are required for full virulence. Δcga1 mutants of C. heterostrophus were less infective of several maize varieties under most conditions, but not all, as virulence was nearly normal on detached leaves. This difference could be related to the rapid senescence of detached leaves, since delaying senescence with cytokinin also had differential effects on the virulence of the wild type and the Δcga1 mutant. In particular, detached leaves may provide a more readily available nutrient source than attached leaves. Decreased fitness of Δcga1 as a pathogen may reflect conditions under which full virulence requires signal transduction through CGA1-mediated pathways. The virulence of these signal transduction mutants is thus affected differentially by the physiological state of the host. 相似文献
17.
18.
19.
Neta Degani Yoav Lubelsky Rotem Ben-Tov Perry Elena Ainbinder Igor Ulitsky 《PLoS genetics》2021,17(7)
Long noncoding RNAs (lncRNAs) have been shown to play important roles in gene regulatory networks acting in early development. There has been rapid turnover of lncRNA loci during vertebrate evolution, with few human lncRNAs conserved beyond mammals. The sequences of these rare deeply conserved lncRNAs are typically not similar to each other. Here, we characterize HOXA-AS3 and HOXB-AS3, lncRNAs produced from the central regions of the HOXA and HOXB clusters. Sequence-similar orthologs of both lncRNAs are found in multiple vertebrate species and there is evident sequence similarity between their promoters, suggesting that the production of these lncRNAs predates the duplication of the HOX clusters at the root of the vertebrate lineage. This conservation extends to similar expression patterns of the two lncRNAs, in particular in cells transiently arising during early development or in the adult colon. Functionally, the RNA products of HOXA-AS3 and HOXB-AS3 regulate the expression of their overlapping HOX5–7 genes both in HT-29 cells and during differentiation of human embryonic stem cells. Beyond production of paralogous protein-coding and microRNA genes, the regulatory program in the HOX clusters therefore also relies on paralogous lncRNAs acting in restricted spatial and temporal windows of embryonic development and cell differentiation. 相似文献
20.
Luca Antonioli Maria Cecilia Giron Rocchina Colucci Carolina Pellegrini Deborah Sacco Valentina Caputi Genny Orso Marco Tuccori Carmelo Scarpignato Corrado Blandizzi Matteo Fornai 《PloS one》2014,9(12)