全文获取类型
收费全文 | 149篇 |
免费 | 27篇 |
专业分类
176篇 |
出版年
2022年 | 1篇 |
2021年 | 2篇 |
2020年 | 2篇 |
2018年 | 2篇 |
2017年 | 3篇 |
2016年 | 4篇 |
2015年 | 6篇 |
2014年 | 6篇 |
2013年 | 12篇 |
2012年 | 9篇 |
2011年 | 5篇 |
2010年 | 6篇 |
2009年 | 8篇 |
2008年 | 5篇 |
2007年 | 5篇 |
2006年 | 4篇 |
2005年 | 7篇 |
2004年 | 6篇 |
2003年 | 11篇 |
2002年 | 11篇 |
2001年 | 8篇 |
2000年 | 3篇 |
1999年 | 3篇 |
1998年 | 5篇 |
1997年 | 1篇 |
1996年 | 2篇 |
1994年 | 1篇 |
1992年 | 7篇 |
1991年 | 1篇 |
1990年 | 4篇 |
1989年 | 4篇 |
1988年 | 2篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1985年 | 3篇 |
1984年 | 2篇 |
1981年 | 5篇 |
1977年 | 1篇 |
1973年 | 1篇 |
1967年 | 2篇 |
1966年 | 1篇 |
1965年 | 1篇 |
1951年 | 1篇 |
1939年 | 1篇 |
排序方式: 共有176条查询结果,搜索用时 0 毫秒
91.
Nahrendorf M Hiller KH Greiser A Kohler S Neuberger T Hu K Waller C Albrecht M Neubauer S Haase A Ertl G Bauer WR 《American journal of physiology. Heart and circulatory physiology》2003,285(6):H2712-H2721
Our purpose was to study morphological, functional, and metabolic changes induced by chronic ischemia in myocardium supplied by the stenotic vessel and in the remote area by MR techniques. A new technique of image fusion is proposed for analysis of coronary artery stenosis involving coronary MR angiography and spectroscopic imaging. Cine-MRI was performed 2 wk after induction of coronary stenosis. Global heart function and regional wall thickening were determined in 11 Wistar rats with stenosis and compared with 7 control rats. Two weeks after stenosis was induced, spin-labeling MRI for measurement of perfusion was performed in 14 isolated hearts. In eight isolated hearts with coronary stenosis, MR spectroscopy was performed, followed by angiography. 31P metabolite maps were fused with three-dimensional coronary angiograms. Induction of stenosis led to reduced segmental wall thickening (control: 75 +/- 9%, ischemic region: 9 +/- 3%, P < 0.05 vs. control) but also to impaired function of the remote region and lower cardiac output. Perfusion was reduced by 74.9 +/- 4.0% within ischemic segments compared with a septal control region. The phosphocreatine (PCr)/ATP ratio as a marker of ischemia was reduced in the region associated with stenosis (1.09 +/- 0.09) compared with remote (1.27 +/- 0.08) and control hearts (1.43 +/- 0.08; P < 0.05). The histological fraction of fibrosis within the ischemic region (12.8 +/- 1.4%) correlated to ATP signal reduction from remote to the ischemic region (r = 0.71, P < 0.05), but not to reduced wall thickening. Coronary narrowing caused declining function accompanied by diminished PCr/ATP, indicating impaired energy metabolism. Neither decline of function nor PCr signal decline correlated to fraction of fibrosis in histology. In contrast, reduction of ATP correlated to fibrosis and therefore to loss of viability. Impaired function within the ischemic region is associated with decreased PCr. Function of the remote region was affected as well. The fusion of PCr metabolite maps and the coronary angiogram may help to assess coronary morphology and resulting metabolic changes simultaneously. 相似文献
92.
The maize low-phytic acid mutant lpa2 is caused by mutation in an inositol phosphate kinase gene 总被引:12,自引:0,他引:12
Reduced phytic acid content in seeds is a desired goal for genetic improvement in several crops. Low-phytic acid mutants have been used in genetic breeding, but it is not known what genes are responsible for the low-phytic acid phenotype. Using a reverse genetics approach, we found that the maize (Zea mays) low-phytic acid lpa2 mutant is caused by mutation in an inositol phosphate kinase gene. The maize inositol phosphate kinase (ZmIpk) gene was identified through sequence comparison with human and Arabidopsis Ins(1,3,4)P(3) 5/6-kinase genes. The purified recombinant ZmIpk protein has kinase activity on several inositol polyphosphates, including Ins(1,3,4)P(3), Ins(3,5,6)P(3), Ins(3,4,5,6)P(4), and Ins(1,2,5,6)P(4). The ZmIpk mRNA is expressed in the embryo, the organ where phytic acid accumulates in maize seeds. The ZmIpk Mutator insertion mutants were identified from a Mutator F(2) family. In the ZmIpk Mu insertion mutants, seed phytic acid content is reduced approximately 30%, and inorganic phosphate is increased about 3-fold. The mutants also accumulate myo-inositol and inositol phosphates as in the lpa2 mutant. Allelic tests showed that the ZmIpk Mu insertion mutants are allelic to the lpa2. Southern-blot analysis, cloning, and sequencing of the ZmIpk gene from lpa2 revealed that the lpa2-1 allele is caused by the genomic sequence rearrangement in the ZmIpk locus and the lpa2-2 allele has a nucleotide mutation that generated a stop codon in the N-terminal region of the ZmIpk open reading frame. These results provide evidence that ZmIpk is one of the kinases responsible for phytic acid biosynthesis in developing maize seeds. 相似文献
93.
Novel, chimpanzee serotype 68-based adenoviral vaccine carrier for induction of antibodies to a transgene product 总被引:3,自引:0,他引:3 下载免费PDF全文
Xiang Z Gao G Reyes-Sandoval A Cohen CJ Li Y Bergelson JM Wilson JM Ertl HC 《Journal of virology》2002,76(6):2667-2675
An E1-deletion-containing adenoviral recombinant based on the chimpanzee serotype 68 (AdC68) was developed to express the rabies virus glycoprotein. Mice immunized with this construct (AdC68rab.gp) developed antibodies to rabies virus and remained resistant to challenge with an otherwise lethal dose of rabies virus. In na?ve mice immunized intranasally, the rabies virus-specific antibody responses elicited by AdC68rab.gp were comparable with regard to both titers and isotype profiles to those induced by an adenoviral recombinant based on human serotype 5 (Adhu5) expressing the same transgene product. In contrast, subcutaneous immunization with the AdC68rab.gp vaccine resulted in markedly lower antibody responses to the rabies virus glycoprotein than the corresponding Adhu5 vaccine. Antibodies from AdC68rab.gp-immunized mice were strongly biased towards the immunoglobulin G2a isotype. The antibody response to the rabies virus glycoprotein presented by Adhu5rab.gp was severely compromised in animals preexposed to the homologous adenovirus. In contrast, the rabies virus-specific antibody response to the AdC68rab.gp vaccine was at most marginally affected by preexisting immunity to common human adenovirus serotypes, such as 2, 4, 5, 7, and 12. This novel vaccine carrier thus offers a distinct advantage over adenoviral vaccines based on common human serotypes. 相似文献
94.
Effect of preexisting immunity to adenovirus human serotype 5 antigens on the immune responses of nonhuman primates to vaccine regimens based on human- or chimpanzee-derived adenovirus vectors 下载免费PDF全文
McCoy K Tatsis N Korioth-Schmitz B Lasaro MO Hensley SE Lin SW Li Y Giles-Davis W Cun A Zhou D Xiang Z Letvin NL Ertl HC 《Journal of virology》2007,81(12):6594-6604
In this study we compared a prime-boost regimen with two serologically distinct replication-defective adenovirus (Ad) vectors derived from chimpanzee serotypes C68 and C1 expressing Gag, Pol, gp140, and Nef of human immunodeficiency virus type 1 with a regimen in which replication-defective Ad vectors of the human serotype 5 (AdHu5) were given twice. Experiments were conducted in rhesus macaques that had or had not been preexposed to antigens of AdHu5. There was no significant difference in T-cell responses tested from peripheral blood of the different groups, although responses were overall highest in nonpreexposed animals immunized with the chimpanzee Ad vectors. Preexisting immunity to AdHu5 completely inhibited induction of transgene product-specific antibodies by the AdHu5 vectors without affecting antibody responses to the chimpanzee vectors. Upon euthanasia, T-cell responses were tested from a number of tissues. Preexisting immunity to AdHu5, commonly found in humans, changed the homing pattern of vaccine-induced T cells. In AdHu5-preexposed animals vaccinated with the chimpanzee Ad vectors, frequencies of transgene-specific T cells were higher in spleens than in blood, and in most preexposed animals vaccinated either with AdHu5 vectors or chimpanzee adenovirus vectors, frequencies of such T cells were exceptionally high in livers. The latter results indicate that analysis of T-cell responses solely from blood mononuclear cells of vaccine recipients may not suffice to compare the potencies of different vaccine regimens. 相似文献
95.
Eric Cornes Montserrat Porta-De-La-Riva David Aristizábal-Corrales Ana María Brokate-Llanos Francisco Javier García-Rodríguez Iris Ertl Mònica Díaz Laura Fontrodona Kadri Reis Robert Johnsen David Baillie Manuel J. Mu?oz Mihail Sarov Denis Dupuy Julián Cerón 《RNA (New York, N.Y.)》2015,21(9):1544-1553
96.
Carolyn J. Lawrence-Dill Robyn L. Allscheid Albert Boaitey Todd Bauman Edward S. Buckler IV Jennifer L. Clarke Christopher Cullis Jack Dekkers Cassandra J. Dorius Shawn F. Dorius David Ertl Matthew Homann Guiping Hu Mary Losch Eric Lyons Brenda Murdoch Zahra-Katy Navabi Somashekhar Punnuri Fahad Rafiq James M. Reecy Patrick S. Schnable Nicole M. Scott Moira Sheehan Xavier Sirault Margaret Staton Christopher K. Tuggle Alison Van Eenennaam Rachael Voas 《PLoS computational biology》2022,18(4)
97.
The target cell specificity of antiviral cytolytic T-lymphocyte (CTL) clones is influenced by in vitro tissue culture conditions. We have demonstrated that high concentrations of lymphokines such as recombinant interleukin-2 (rIL-2) induce killer T cells to lose virus specificity. Our experiments do not indicate that the cells become like natural killer (NK) cells. The loss of specificity is more general and can be reversed upon culture in more physiological concentrations of lymphokines. The implications of these observations for the pathogenesis of viral infection is discussed. 相似文献
98.
Robin P. Ertl William L. Alworth Gary W. Winston 《Journal of biochemical and molecular toxicology》1999,13(1):17-27
Six substituted alkoxyphenoxazones (resorufins) and four inhibitors of P450‐dependent mixed‐function oxygenases (MFO) were used to probe the breadth and extent of P450 metabolism induced by pretreatment with five xenobiotic chemicals in liver microsomes of the American alligator, Alligator mississippiensis. Phenobarbital (PB), 3‐methylcholanthrene (3MC), and PB–3MC co‐pretreatment elicited major induction of alligator MFO activity measured by alkoxyresorufin O‐dealkylation (AROD). The induced levels of activities observed with appropriate substrate, 7‐ethoxy, 7‐methoxy, 2‐phenylbenzyloxy, 7‐pentoxy, or 7‐benzyloxyresorufin (EROD, MROD, PBROD, PROD and BROD, respectively), were 10 to 100 times lower in alligator as compared to rat. The exception was a higher level of isopropoxyresorufin O‐dealkylation (IPROD) in alligator. The induction regimes used in alligator and rat revealed marked differences in substrate preference, discrimination factors (DF) for various inducible P450 isoforms. EROD, a classic indicator of CYP1A activity in rat, had a low DF in alligator. MROD was the best discriminator in alligator of CYP1A‐type induction. In contrast to rats, pretreatment of alligators with Aroclor 1254, 2,2′,4,4′ tetrachlorobiphenyl, and clofibrate caused minor alterations in AROD relative to untreated controls. The inhibitors, α‐napthaflavone, 1‐ethynylpyrene, SKF 525A, and 9‐ethynylphenanthrene, inhibited AROD activity of the expected P450 isoform. For example, 10 μM α‐napthaflavone inhibited liver microsomal EROD catalyzed by 3MC‐inducible isoforms from alligator by 90% and from rat by 97%. Similarly, 10 μM SKF 525A inhibited PROD catalyzed by PB‐inducible isoforms by 63% and 79% in alligator and rat liver microsomes, respectively. To the best of our knowledge, the present studies are the first to show PB induction of P450 activities typical of the mammalian CYP2 family and their inhibition with classical inhibitors in alligator liver. While our data indicate metabolism of P450 substrates with preferences to certain isoforms, it remains to be established which isoforms exert catalytic function in alligator and whether these are homologues or orthologues of mammalian isoforms. © 1998 John Wiley & Sons, Inc. J Biochem Toxicol 13: 17–27, 1999 相似文献
99.
Induction of genital immunity by DNA priming and intranasal booster immunization with a replication-defective adenoviral recombinant. 总被引:7,自引:0,他引:7
Mice immunized through different routes such as i.m., intradermally, or intratracheally with a DNA vaccine to rabies virus developed high titers of serum Ab but only borderline levels of mucosal Abs determined from vaginal secretions. DNA vaccines given by either route enhanced vaginal IgA and IgG2a secretion upon a subsequent intranasal booster immunization with an E1-deleted adenoviral recombinant expressing the same Ag of rabies virus. DNA vaccine priming reduced the Ab response to the adenoviral Ags and counterbalanced the impaired B cell response to the rabies virus Ag expressed by the adenoviral recombinant in mice preimmune to adenovirus. The vaginal B cell response could further be enhanced by using the Th2-type cytokines IL-4 or IL-5 as genetic adjuvants concomitantly with the DNA vaccine before intranasal booster immunization with the recombinant vaccine. 相似文献
100.
Gülmisal Güder Susanne Brenner Christiane E Angermann Georg Ertl Matthias Held Alfred P Sachs Jan-Willem Lammers Pieter Zanen Arno W Hoes Stefan St?rk Frans H Rutten 《Respiratory research》2012,13(1):13