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171.
Functional analysis of Hes-1 in preadipocytes 总被引:3,自引:0,他引:3
172.
173.
Dai-Shi Su John J. Lim Elizabeth Tinney Bang-Lin Wan Mary Beth Young Kenneth D. Anderson Deanne Rudd Vandna Munshi Carolyn Bahnck Peter J. Felock Meiqing Lu Ming-Tain Lai Sinoeun Touch Gregory Moyer Daniel J. DiStefano Jessica A. Flynn Yuexia Liang Rosa Sanchez Sridhar Prasad Youwei Yan Neville J. Anthony 《Bioorganic & medicinal chemistry letters》2009,19(17):5119-5123
174.
Daniel Rosen Alexander M. Lewis Akiko Mizote Justyn M. Thomas Parvinder K. Aley Sridhar R. Vasudevan Raman Parkesh Antony Galione Minoru Izumi A. Ganesan Grant C. Churchill 《The Journal of biological chemistry》2009,284(50):34930-34934
Nicotinic acid adenine dinucleotide phosphate (NAADP) is a Ca2+-releasing messenger. Biological data suggest that its receptor has two binding sites: one high-affinity locking site and one low-affinity opening site. To directly address the presence and function of these putative binding sites, we synthesized and tested analogues of the NAADP antagonist Ned-19. Ned-19 itself inhibits both NAADP-mediated Ca2+ release and NAADP binding. A fluorometry bioassay was used to assess NAADP-mediated Ca2+ release, whereas a radioreceptor assay was used to assess binding to the NAADP receptor (only at the high-affinity site). In Ned-20, the fluorine is para rather than ortho as in Ned-19. Ned-20 does not inhibit NAADP-mediated Ca2+ release but inhibits NAADP binding. Conversely, Ned-19.4 (a methyl ester of Ned-19) inhibits NAADP-mediated Ca2+ release but cannot inhibit NAADP binding. Furthermore, Ned-20 prevents the self-desensitization response characteristic of NAADP in sea urchin eggs, confirming that this response is mediated by a high-affinity allosteric site to which NAADP binds in the radioreceptor assay. Collectively, these data provide the first direct evidence for two binding sites (one high- and one low-affinity) on the NAADP receptor. 相似文献
175.
Bryon S. Donohoe Michael J. Selig Sridhar Viamajala Todd B. Vinzant William S. Adney Michael E. Himmel 《Biotechnology and bioengineering》2009,103(3):480-489
In general, pretreatments are designed to enhance the accessibility of cellulose to enzymes, allowing for more efficient conversion. In this study, we have detected the penetration of major cellulases present in a commercial enzyme preparation (Spezyme CP) into corn stem cell walls following mild‐, moderate‐ and high‐severity dilute sulfuric acid pretreatments. The Trichoderma reesei enzymes, Cel7A (CBH I) and Cel7B (EG I), as well as the cell wall matrix components xylan and lignin were visualized within digested corn stover cell walls by immuno transmission electron microscopy (TEM) using enzyme‐ and polymer‐specific antibodies. Low severity dilute‐acid pretreatment (20 min at 100°C) enabled <1% of the thickness of secondary cell walls to be penetrated by enzyme, moderate severity pretreatment at (20 min at 120°C) allowed the enzymes to penetrate ~20% of the cell wall, and the high severity (20 min pretreatment at 150°C) allowed 100% penetration of even the thickest cell walls. These data allow direct visualization of the dramatic effect dilute‐acid pretreatment has on altering the condensed ultrastructure of biomass cell walls. Loosening of plant cell wall structure due to pretreatment and the subsequently improved access by cellulases has been hypothesized by the biomass conversion community for over two decades, and for the first time, this study provides direct visual evidence to verify this hypothesis. Further, the high‐resolution enzyme penetration studies presented here provide insight into the mechanisms of cell wall deconstruction by cellulolytic enzymes. Biotechnol. Bioeng. 2009;103: 480–489. © 2009 Wiley Periodicals, Inc. 相似文献
176.
Julien Bonnel April Khademi Sridhar Krishnan Cornel Ioana 《Biomedical signal processing and control》2009,4(1):7-15
This paper presents a novel system to compute the automated classification of wireless capsule endoscope images. Classification is achieved by a classical statistical approach, but novel features are extracted from the wavelet domain and they contain both color and texture information. First, a shift-invariant discrete wavelet transform (SIDWT) is computed to ensure that the multiresolution feature extraction scheme is robust to shifts. The SIDWT expands the signal (in a shift-invariant way) over the basis functions which maximize information. Then cross-co-occurrence matrices of wavelet subbands are calculated and used to extract both texture and color information. Canonical discriminant analysis is utilized to reduce the feature space and then a simple 1D classifier with the leave one out method is used to automatically classify normal and abnormal small bowel images. A classification rate of 94.7% is achieved with a database of 75 images (41 normal and 34 abnormal cases). The high success rate could be attributed to the robust feature set which combines multiresolutional color and texture features, with shift, scale and semi-rotational invariance. This result is very promising and the method could be used in a computer-aided diagnosis system or a content-based image retrieval scheme. 相似文献
177.
Stephanie L. Davis Nicholas A. Be Gyanu Lamichhane Sridhar Nimmagadda Martin G. Pomper William R. Bishai Sanjay K. Jain 《PloS one》2009,4(7)
Background
Bacteria can be selectively imaged in experimentally-infected animals using exogenously administered 1-(2′deoxy-2′-fluoro-β-D-arabinofuranosyl)-5-[125I]-iodouracil ([125I]-FIAU), a nucleoside analog substrate for bacterial thymidine kinase (TK). Our goal was to use this reporter and develop non-invasive methods to detect and localize Mycobacterium tuberculosis.Methodology/Principal Findings
We engineered a M. tuberculosis strain with chromosomally integrated bacterial TK under the control of hsp60 - a strong constitutive mycobacterial promoter. [125I]FIAU uptake, antimicrobial susceptibilities and in vivo growth characteristics were evaluated for this strain. Using single photon emission computed tomography (SPECT), M. tuberculosis Phsp60 TK strain was evaluated in experimentally-infected BALB/c and C3HeB/FeJ mice using the thigh inoculation or low-dose aerosol infection models. M. tuberculosis Phsp60 TK strain actively accumulated [125I]FIAU in vitro. Growth characteristics of the TK strain and susceptibility to common anti-tuberculous drugs were similar to the wild-type parent strain. M. tuberculosis Phsp60 TK strain was stable in vivo and SPECT imaging could detect and localize this strain in both animal models tested.Conclusion
We have developed a novel tool for non-invasive assessment of M. tuberculosis in live experimentally-infected animals. This tool will allow real-time pathogenesis studies in animal models of TB and has the potential to simplify preclinical studies and accelerate TB research. 相似文献178.
S. K. Arepalli V. Sridhar J. Venkateswara Rao P. Kavin Kennady Y. Venkateswarlu 《Apoptosis : an international journal on programmed cell death》2009,14(5):729-740
Bioassay directed fractionation and purification led to the successful isolation of a furano sesquiterpene, Methyl 5-[(1E,5E)-2,6-Dimethyl
octa-1,5,7-trienyl] furan-3-carboxylate (MDTFC), a bioactive component from a soft coral, Sinularia kavarittiensis. Its structure was determined by analyzing 1H, 13C NMR and FAB-MS. The results show that MDTFC could efficiently and selectively inhibit the proliferation of several human
cancer cell lines. Among all the cell lines, THP-1 was found to be most sensitive (IC50 29.59 μM), whereas the peripheral blood mononuclear cells were least effected (IC50 464.16 μM). The molecular mechanism of MDTFC mediated apoptosis was investigated for the first time. Induction of apoptosis
in THP-1 cells was characterized by cell membrane blebbing, chromatin condensation, DNA fragmentation, and decrease in level
of pro-caspases 3, 9 and increase in Bax/Bcl-2 ratio. Our results were further strengthened through cleavage of poly (ADP-ribose)
polymerase, reduction of mitochondrial membrane potential (Ψm) and cytosolic release of cytochrome c, which are key events during apoptosis. Moreover, phosphatidyl serine exposure and appearance of sub-G1 peak also demonstrated
cell death, when analyzed by flow cytometry. DNA fragmentation was prevented moderately when pretreated with caspase-9 inhibitor
(Z-LEHD-FMK) and largely with caspase-3 inhibitor (Z-DEVD-FMK). In summary, MDTFC mediated apoptosis involves mitochondria-dependent
pathway and the present compound of marine origin might have a therapeutic value against human cancer cell lines and especially
on leukemia cells. 相似文献
179.
A quick, efficient and convenient method for the regiospecific reductive ring opening of 4,6-O-benzylidene acetals of O-/S-alkyl/aryl glycosides of mono- and disaccharides, leading to the exclusive formation of the corresponding 6-O-benzyl ethers, using sodium cyanoborohydride in the presence of molecular iodine, is reported. It has been observed that common protecting groups such as ethers and esters are well tolerated under the conditions studied. The reaction was proved unsuccessful when applied to a glucosamine-derived benzylidene acetal. 相似文献
180.
Nimmanapalli P. Reddy Polamarasetty Aparoy T. Chandra Mohan Reddy Chandrani Achari P. Ramu Sridhar Pallu Reddanna 《Bioorganic & medicinal chemistry》2010,18(16):5807-5815
Ten novel mono- and di-O-prenylated chalcone derivatives were designed on the basis of a homology derived molecular model of 5-lipoxygenase (5-LOX). The compounds were docked into 5-LOX active site and the binding characteristics were quantified using LUDI. To verify our theoretical assumption, the molecules were synthesized and tested for their 5-LOX inhibitory activities. The synthesis was carried out by Claisen–Schmidt condensation reaction of mono- and di-O-prenylated acetophenones with appropriate aldehydes. 5-LOX in vitro inhibition assay showed higher potency of di-O-prenylated chalcones than their mono-O-prenylated chalcone analogs. Compound 5e exhibited good inhibition with an IC50 at 4 μM. The overall trend for the binding energies calculated and LUDI score was in good qualitative agreement with the experimental data. Further, the compound 5e showed potent anti-proliferative effects (GI50 at 9 μM) on breast cancer cell line, MCF-7. 相似文献