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961.
Erlandsen H Canaves JM Elsliger MA von Delft F Brinen LS Dai X Deacon AM Floyd R Godzik A Grittini C Grzechnik SK Jaroszewski L Klock HE Koesema E Kovarik JS Kreusch A Kuhn P Lesley SA McMullan D McPhillips TM Miller MD Morse A Moy K Ouyang J Page R Robb A Quijano K Schwarzenbacher R Spraggon G Stevens RC van den Bedem H Velasquez J Vincent J Wang X West B Wolf G Hodgson KO Wooley J Wilson IA 《Proteins》2004,54(4):806-809
962.
Schwarzenbacher R Deacon AM Jaroszewski L Brinen LS Canaves JM Dai X Elsliger MA Floyd R Godzik A Grittini C Grzechnik SK Klock HE Koesema E Kovarik JS Kreusch A Kuhn P Lesley SA McMullan D McPhillips TM Miller MD Morse A Moy K Nelson MS Ouyang J Page R Robb A Quijano K Spraggon G Stevens RC van den Bedem H Velasquez J Vincent J von Delft F Wang X West B Wolf G Hodgson KO Wooley J Wilson IA 《Proteins》2004,54(4):801-805
963.
McMullan D Schwarzenbacher R Jaroszewski L von Delft F Klock HE Vincent J Quijano K Abdubek P Ambing E Biorac T Brinen LS Canaves JM Dai X Deacon AM DiDonato M Elsliger MA Eshaghi S Floyd R Godzik A Grittini C Grzechnik SK Hampton E Karlak C Koesema E Kreusch A Kuhn P Levin I McPhillips TM Miller MD Morse A Moy K Ouyang J Page R Reyes R Rezezadeh F Robb A Sims E Spraggon G Stevens RC van den Bedem H Velasquez J Wang X West B Wolf G Xu Q Hodgson KO Wooley J Lesley SA Wilson IA 《Proteins》2004,56(3):615-618
964.
Levin I Schwarzenbacher R McMullan D Abdubek P Ambing E Biorac T Cambell J Canaves JM Chiu HJ Dai X Deacon AM DiDonato M Elsliger MA Godzik A Grittini C Grzechnik SK Hampton E Jaroszewski L Karlak C Klock HE Koesema E Kreusch A Kuhn P Lesley SA McPhillips TM Miller MD Morse A Moy K Ouyang J Page R Quijano K Reyes R Robb A Sims E Spraggon G Stevens RC van den Bedem H Velasquez J Vincent J von Delft F Wang X West B Wolf G Xu Q Hodgson KO Wooley J Wilson IA 《Proteins》2004,56(3):629-633
965.
Fitness of a turnip crinkle virus satellite RNA correlates with a sequence-nonspecific hairpin and flanking sequences that enhance replication and repress the accumulation of virions
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satC, a satellite RNA associated with Turnip crinkle virus (TCV), enhances the ability of the virus to colonize plants by interfering with stable virion accumulation (F. Zhang and A. E. Simon, unpublished data). Previous results suggested that the motif1-hairpin (M1H), a replication enhancer on minus strands, forms a plus-strand hairpin flanked by CA-rich sequence that may be involved in enhancing systemic infection (G. Zhang and A. E. Simon, J. Mol. Biol. 326:35-48, 2003). In this study, sequence and structural requirements of the M1H were further assayed by replacing the 28-base M1H with 10 random bases and then subjecting the pool of satellite RNA to functional selection in plants. Unlike previous results with 28-base replacement sequences (G. Zhang and A. E. Simon, J. Mol. Biol. 326:35-48, 2003), only a few of the 10-base SELEX (systematic evolution of ligands by exponential enrichment) assay winners contained short motifs in their minus-sense orientation that were similar to TCV replication elements. However, all second- and third-round winning replacement sequences folded into hairpins flanked by CA-rich sequence predicted to be more stable on plus strands than minus strands. Plus strands of several of the most fit satellite RNAs contained insertions of CA-rich sequence at the base of their hairpins whose presence correlated with enhanced replication and reduced detection of virions. Deletion of the M1H resulted in no detectable virions despite very low satellite accumulation. These results support the hypothesis that a sequence-nonspecific plus-strand hairpin brings together flanking CA-rich sequences in the M1H region that confers fitness to satC by reducing the accumulation of stable virions. 相似文献
966.
Apocytochrome c (Apocyt. c) is the precursor of cytochrome c. It is synthesized in the cytosol and posttranslationally imported
into mitochondria. In order to determine the crucial sequence in apocyt. c translocation, deleted mutant and chemically synthesized
peptides with different length were used. Obtained results showed that sequence 68–88 of apocyt. c plays a critical role in
its insertion into membrane and binding to mitochondria. 相似文献
967.
Differential effects of IL-1 alpha and IL-1 beta on tumorigenicity patterns and invasiveness 总被引:4,自引:0,他引:4
Song X Voronov E Dvorkin T Fima E Cagnano E Benharroch D Shendler Y Bjorkdahl O Segal S Dinarello CA Apte RN 《Journal of immunology (Baltimore, Md. : 1950)》2003,171(12):6448-6456
In this study, we show that distinct compartmentalization patterns of the IL-1 molecules (IL-1alpha and IL-1beta), in the milieu of tumor cells that produce them, differentially affect the malignant process. Active forms of IL-1, namely precursor IL-1alpha (pIL-1alpha), mature IL-1beta (mIL-1beta), and mIL-1beta fused to a signal sequence (ssIL-1beta), were transfected into an established fibrosarcoma cell line, and tumorigenicity and antitumor immunity were assessed. Cell lines transfected with pIL-1alpha, which expresses IL-1alpha on the membrane, fail to develop local tumors and activate antitumor effector mechanisms, such as CTLs, NK cells, and high levels of IFN-gamma production. Cells transfected with secretable IL-1beta (mIL-1beta and ssIL-1beta) were more aggressive than wild-type and mock-transfected tumor cells; ssIL-1beta transfectants even exhibited metastatic tumors in the lungs of mice after i.v. inoculation (experimental metastasis). In IL-1beta tumors, increased vascularity patterns were observed. No detectable antitumor effector mechanisms were observed in spleens of mice injected with IL-1beta transfectants, mock-transfected or wild-type fibrosarcoma cells. Moreover, in spleens of mice injected with IL-1beta transfectants, suppression of polyclonal mitogenic responses (proliferation, IFN-gamma and IL-2 production) to Con A was observed, suggesting the development of general anergy. Histologically, infiltrating mononuclear cells penetrating the tumor were seen at pIL-1alpha tumor sites, whereas in mIL-1beta and ssIL-1beta tumor sites such infiltrating cells do not penetrate inside the tumor. This is, to our knowledge, the first report on differential, nonredundant, in vivo effects of IL-1alpha and IL-1beta in malignant processes; IL-1alpha reduces tumorigenicity by inducing antitumor immunity, whereas IL-1beta promotes invasiveness, including tumor angiogenesis, and also induces immune suppression in the host. 相似文献
968.
The two upstream open reading frames of oncogene mdm2 have different translational regulatory properties 总被引:5,自引:0,他引:5
Jin X Turcott E Englehardt S Mize GJ Morris DR 《The Journal of biological chemistry》2003,278(28):25716-25721
969.
发根农杆菌(Agrobacterium rhizogenes)的建立对植物功能基因的验证具有重要意义,为了在桉树(Eucalyptus)中建立发根农杆菌介导的遗传转化体系,本研究以不同的发根农杆菌菌株侵染尾巨桉(Eucalyptus urophylla × E. grandis)的叶片和茎段,确定合适的农杆菌菌株和外植体类型,在此基础上开展农杆菌浓度、侵染时间对毛状根诱导的影响。结果表明:采用发根农杆菌菌株MSU440,以叶片为外植体进行发根诱导,最高获得了81.0%的毛状根诱导率,毛状根平均根长达到3.23 cm。在发根农杆菌浓度为OD600=0.3、侵染时间为30 min时,共培养48 h后经过20 mg·L-1卡那霉素筛选培养,通过PCR分子鉴定和GUS染色证实外源基因稳定地整合在桉树毛状根基因组中,转化率达20.2%。初步建立了发根农杆菌介导的桉树遗传转化体系,为桉树基因功能鉴定和进一步的转基因育种奠定基础。 相似文献
970.
Endothelium-derived nitric oxide (NO) is a potent vasodilator in the cardiovascular system. Several lines of experimental evidence suggest that NO or NO equivalents may also be generated in the blood. However, blood contains a large amount of hemoglobin (Hb) in red blood cells (RBCs). The RBC-encapsulated Hb can react very quickly with NO, which is only limited by the rate of NO diffusion into the RBCs. It is unclear what the possible NO concentration levels in blood are and how the NO diffusion coefficient (D) and the permeability (Pm) of RBC membrane to NO affect the level of NO concentration. In this study, a steady-state concentration experimental method combined with a spherical diffusion model are presented for determining D and Pm and examining the effect of NO generation rate (V0) and hematocrit (Hct) on NO concentration. It was determined that Pm is 4.5 +/- 1.5 cm/s and D is 3410 +/- 50 microm2/s at 37 degrees C. Simulations based on experimental parameters show that, when the rate of NO formation is as high as 100 nm/s, the maximal NO concentration in blood is below 0.012 nM at Pm = 4.5 cm/s and Hct = 45%. Thus, it is unlikely that NO is directly exported or generated from the RBC as an intravascular signaling molecule, because its concentration would be too low to exert a physiological role. Furthermore, our results suggest that, if RBCs export NO bioactivity, this would be through NO-derived species that can release or form NO rather than NO itself. 相似文献