全文获取类型
收费全文 | 653篇 |
免费 | 29篇 |
出版年
2023年 | 2篇 |
2022年 | 2篇 |
2021年 | 8篇 |
2019年 | 6篇 |
2018年 | 6篇 |
2017年 | 5篇 |
2016年 | 11篇 |
2015年 | 8篇 |
2014年 | 17篇 |
2013年 | 38篇 |
2012年 | 38篇 |
2011年 | 36篇 |
2010年 | 14篇 |
2009年 | 19篇 |
2008年 | 37篇 |
2007年 | 28篇 |
2006年 | 32篇 |
2005年 | 40篇 |
2004年 | 30篇 |
2003年 | 25篇 |
2002年 | 31篇 |
2001年 | 20篇 |
2000年 | 15篇 |
1999年 | 27篇 |
1998年 | 13篇 |
1997年 | 10篇 |
1996年 | 5篇 |
1995年 | 10篇 |
1994年 | 10篇 |
1993年 | 12篇 |
1992年 | 24篇 |
1991年 | 11篇 |
1990年 | 15篇 |
1989年 | 9篇 |
1988年 | 14篇 |
1987年 | 7篇 |
1986年 | 7篇 |
1985年 | 7篇 |
1984年 | 2篇 |
1982年 | 3篇 |
1981年 | 2篇 |
1980年 | 2篇 |
1979年 | 2篇 |
1978年 | 6篇 |
1976年 | 2篇 |
1975年 | 2篇 |
1973年 | 3篇 |
1971年 | 2篇 |
1969年 | 3篇 |
1966年 | 1篇 |
排序方式: 共有682条查询结果,搜索用时 15 毫秒
671.
672.
An unstable mutant R factor conferring only chloramphenicol (CM) resistance was obtained by spontaneous segregation. After storage in broth culture, a stable CM-resistant mutant was obtained and its CM-resistance could not be cured by treatment with acriflavine or transduced to a recombination-deficient strain of Escherichia coli K12. Recombinational analysis indicated that the cml gene governing CM resistance had been integrated into the E. coli chromosome and closely linked with met B locus. The cml gene was co-transduced with both met and arg markers by phage P1, and the linkage order was considered to be mtl-cml-met-arg-thi. When the strain carrying this chromosomal CM-resistance was infected with a transferable R (TC) factor capable of conferring tetracycline (TC) resistance, the CM-resistance became transferable by conjugation. This mechanism is considered to account for the formation of the recombinant R (TC.CM) factor. 相似文献
673.
Ito Masamitsu; Kawakami Yasuo; Ichinose Yoshiho; Fukashiro Senshi; Fukunaga Tetsuo 《Journal of applied physiology》1998,85(4):1230-1235
Fascicle length, pennation angle, and tendonelongation of the human tibialis anterior were measured in vivo byultrasonography. Subjects (n = 9) wererequested to develop isometric dorsiflexion torque gradually up tomaximal at the ankle joint angle of 20° plantarflexion from theanatomic position. Fascicle length shortened from 90 ± 7 to 76 ± 7 (SE) mm, pennation angle increased from 10 ± 1 to 12 ± 1°, and tendon elongation increased up to 15 ± 2 mm with gradedforce development up to maximum. The tendon stiffness increased withincreasing tendon force from 10 N/mm at 0-20 N to 32 N/mm at240-260 N. Young's modulus increased from 157 MPa at 0-20 Nto 530 MPa at 240-260 N. It can be concluded that, in isometriccontractions of a human muscle, mechanical work, some of which isabsorbed by the tendinous tissue, is generated by the shortening ofmuscle fibers and that ultrasonography can be used to determine thestiffness and Young's modulus for human tendons. 相似文献
674.
Puff application of complement component C5a (5 x 10(-8) M) onto peritoneal macrophages from thioglycollate-stimulated mice induced two kinds of outward current at a holding potential of -68 mV, a slowly-rising sustained outward current and a spike-like transient outward current. Quinidine (2 x 10(-4) M) and tetraethylammonium (10(-2) M) partially suppressed both types of outward current. Charybdotoxin (2 x 10(-6) M) markedly suppressed the spike-like outward current. Reversal potentials in bath solutions of different external K+ concentrations were dependent only on K+ concentrations. The transient current was not suppressed in Ca(2+)-free EGTA-containing solution, but was completely abolished in BAPTA-containing solution. One kind of single channel responding to C5a, which has a single-channel conductance of 29 pS, was recorded from cell-attached patches. These results suggest that C5a activates a Ca(2+)-dependent and another type of K+ current. 相似文献
675.
Regulation of Polyphosphoinositide Metabolism in Pea Plasma Membranes by Elicitor and Suppressor from a Pea Pathogen, Mycosphaerella pinodes 总被引:1,自引:0,他引:1
Toyoda Kazuhiro; Shirashi Noriaki; Yoshioka Hirofumi; Yamada Tetsuji; Ichinose Yuki; Oku Hachiro 《Plant & cell physiology》1992,33(4):445-452
Effects of the elicitor and the suppressor from a pea pathogen,Mycosphaerella pinodes, on polyphosphoinositide metabolism inpea plasma membranes were examined in vitro. Lipid phosphorylationin the isolated pea plasma membrane was drastically stimulatedby the elicitor, but markedly inhibited by the suppressor. Asimilar inhibitory effect was observed by the treatment withorthovanadate or K-252a that blocked pisatin production inducedby the elicitor. Neomycin, an aminoglycoside antibiotic thatinteracts with the polyphosphoinositide metabolism, also affectedthe lipid phosphorylation in vitro and blocked the elicitor-inducedaccumulation of pisatin in vivo. These results suggest thatrapid changes of polyphosphoinositide metabolism in pea plasmamembranes is one of indispensable processes during the elicitationof defense responses. (Received January 22, 1992; Accepted March 23, 1992) 相似文献
676.
677.
Noriyuki Kasai Shinji Hirosue Hirofumi Ichinose Miho Ohta 《Biochemical and biophysical research communications》2009,387(1):103-123
We cloned full-length cDNAs of more than 130 cytochrome P450s (P450s) derived from Phanerochaete chrysosporium, and successfully expressed 70 isoforms using a co-expression system of P. chrysosporium P450 and yeast NADPH-P450 reductase in Saccharomyces cerevisiae. Of these P450s, a microsomal P450 designated as PcCYP65a2 consists of 626 amino acid residues with a molecular mass of 68.3 kDa. Sequence alignment of PcCYP65a2 and human CYP1A2 revealed a unique structure of PcCYP65a2. Functional analysis of PcCYP65a2 using the recombinant S. cerevisiae cells demonstrated that this P450 catalyzes 3′-hydroxylation of naringenin to yield eriodictyol, which has various biological and pharmacological properties. In addition, the recombinant S. cerevisiae cells expressing PcCYP65a2 metabolized such polyaromatic compounds as dibenzo-p-dioxin (DD), 2-monochloroDD, biphenyl, and naphthalene. These results suggest that PcCYP65a2 is practically useful for both bioconversion and bioremediation. 相似文献
678.
679.
680.
Shizuko Sei 《Letters in Peptide Science》2003,10(3-4):269-286
The advent of highly active antiretroviral therapy (HAART) was once perceived to havetransformed deadly HIV/AIDS into a treatable,
chronic infectious disease. However, mountingevidence now suggests that the prevalence of multi-drug resistant HIV (MDR-HIV)
infection issteadily rising among newly infected individuals in the HAART-experienced countries, raising aconcern for a future
outbreak of MDR-HIV/AIDS. Our global fight against AIDS must include sustainedeffort to search and discover a new therapeutic
modality for HIV infection. Of plausible viraltargets explored to date, HIV gene-targeting approach has not yet seen a considerable
success invivo. The pursuit of anti-HIV gene intervention should include the identification of critical genetargets as well
as the optimization of biomolecules that can effectively interact with theintended targets. Using unmodified peptide nucleic
acids (PNA) as a biomolecular tool, we discovereda potentially critical HIV gene segment within gag-polencoding gene. Antisense PNA targetingthis specific region effectively disrupted a translation of HIV gag-polmRNA, abolishing thevirion production from chronically HIV-infected cells. This exemplifies the possibility that epigenic
HIV inhibitors may be developed in the coming years, if emerging novel technologies permitsufficient and stable in vivo delivery
of PNA or other similarly effective biomolecules. 相似文献