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Carla Abdo Nabil Nemer Georges Nemer Yusuf Abou Jawdah Hagop Atamian Nasri S. Kawar 《BioControl》2008,53(2):341-352
Larvae of the cedar web-spinning sawfly, Cephalcia tannourinensis Chevin (Hymenoptera: Pamphiliidae), infected with a white fungus were collected from the Tannourine-Hadath El-Jebbeh cedar
forest. Macro- and micro-morphological data based on the examination of colonies, conidiophores, and conidial shape of the
fungus suggested a Beauveria species. Sequence analysis of the internal transcribed spacer regions of the isolated fungus showed that it is most closely
related to isolates of B. bassiana Clade C. The present study showed that the isolated B. bassiana is a naturally occurring entomopathogenic fungus parasitizing the larvae of C. tannourinensis in Lebanon. Laboratory bioassays showed that B. bassiana caused high mortality of eggs and larvae. The infected eggs turned brownish in color, while larvae of the first instar ceased
feeding and showed immobility and rigidity within 5 days and before sporulating conidial mat appeared on their cuticle. Second
and third larval instars took longer time to show fungal sporulation: mortalities ranged between 85 and 100% within 7 days
when treated with different conidial concentrations. The efficacy of control of C. tannourinensis using B. bassiana was higher or equal to the reference insect growth regulator, diflubenzuron, suggesting the possibility of its success as
a biological control agent. 相似文献
125.
It has become increasingly difficult to find an area of cell biology in which lipids do not have important, if not key, roles as signalling and regulatory molecules. The rapidly expanding field of bioactive lipids is exemplified by many sphingolipids, such as ceramide, sphingosine, sphingosine-1-phosphate (S1P), ceramide-1-phosphate and lyso-sphingomyelin, which have roles in the regulation of cell growth, death, senescence, adhesion, migration, inflammation, angiogenesis and intracellular trafficking. Deciphering the mechanisms of these varied cell functions necessitates an understanding of the complex pathways of sphingolipid metabolism and the mechanisms that regulate lipid generation and lipid action. 相似文献
126.
Bielawska A Bielawski J Szulc ZM Mayroo N Liu X Bai A Elojeimy S Rembiesa B Pierce J Norris JS Hannun YA 《Bioorganic & medicinal chemistry》2008,16(2):1032-1045
Novel isosteric analogs of the ceramidase inhibitors (1S,2R)-N-myristoylamino-phenylpropanol-1 (d-e-MAPP) and (1R,2R)-N-myristoylamino-4'-nitro-phenylpropandiol-1,3 (B13) with modified targeting and physicochemical properties were developed and evaluated for their effects on endogenous bioactive sphingolipids: ceramide, sphingosine, and sphingosine 1-phosphate (Cer, Sph, and S1P) in MCF7 cells as determined by high-performance liquid chromatography-mass spectrometry (HPLC-MS/MS). Time- and dose-response studies on the effects of these compounds on Cer species and Sph levels, combined with structure-activity relationship (SAR) data, revealed 4 distinct classes of analogs which were predominantly defined by modifications of the N-acyl-hydrophobic interfaces: N-acyl-analogs (class A), urea-analogs (class B), N-alkyl-analogs (class C), and omega-cationic-N-acyl analogs (class D). Signature patterns recognized for two of the classes correspond to the cellular compartment of action of the new analogs, with class D acting as mitochondriotropic agents and class C compounds acting as lysosomotropic agents. The neutral agents, classes A and B, do not have this compartmental preference. Moreover, we observed a close correlation between the selective increase of C(16)-, C(14)-, and C(18)-Cers and inhibitory effects on MCF7 cell growth. The results are discussed in the context of compartmentally targeted regulators of Sph, Cer species, and S1P in cancer cell death, emphasizing the role of C(16)-Cer. These novel analogs should be useful in cell-based studies as specific regulators of Cer-Sph-S1P inter-metabolism, in vitro enzymatic studies, and for therapeutic development. 相似文献
127.
A number of new imine derivatives of 5-amino-1, 3, 4-thiadiazole-2-thiol have been synthesized, and their anti-depressant activity was tested using imipramine as reference drug. Two compounds namely 5-{[1-(4-chlorophenyl)-3-(4-methoxy-phenyl)prop-2-en-1-ylidene]-amino}-5-benzylthio-1, 3,4 -thiadiazole 4i(b) and 5-{[1-(4-chlorophenyl)-3-(4-dimethyl-aminophenyl)-prop-2-en-1-ylidene]amino}-5-benzylthio-1,3,4-thiadiazole 4i(c) have shown significant anti-depressant activity, which decreased immobility time by 77.99% and 76.26% compared to the standard imipramine (82%). All the compounds in the series have passed neurotoxicity tests. 相似文献
128.
Arvind Kumar Gupta Ashraf Yusuf Rangrez Pankaj Verma Anil Chatterji Yogesh S. Shouche 《Indian journal of microbiology》2009,49(2):169-187
Microbial communities in coastal subsurface sediments play an important role in biogeochemical cycles. In this study microbial
communities in tidal subsurface sediments of Balramgari in the state of Orissa, India were investigated using a culture independent
approach. Two 16S rDNA cloned libraries were prepared from the closely located (100 m along the coast) subsurface sediment
samples. Library I sediment samples had higher organic carbon content but lower sand percentage in comparison to Library II.
A total of 310 clone sequences were used for DOTUR analysis which revealed 51 unique phylotypes or operational taxonomic units
(OTUs) for both libraries. The OTUs were affiliated with 13 major lineages of domain bacteria including Proteobacteria (α, β, δ and λ), Acidobacteria, Actinobacteria, Cyanobacteria, Chloroflexi, Firmicutes, Verrucomicrobia, Bacteroidetes, Gemmatimonadetes and TM7. We encountered few pathogenic bacteria such as Aeromonas hydrophila and Ochrobactrum intermedium, in sediment from Library I. ∫-LIBSHUFF comparison depicts that the two libraries were significantly different communities.
Most of the OTUs from both libraries possessed ≥85% to <97% similarity to RDP database sequences depicting the putative presence
of new species, genera and phylum. This work revealed the complex and unique bacterial diversity from coastal habitat of Balramgari
and shows that, in coastal habitat a variability of physical and chemical parameter has a prominent impact on the microbial
community structure. 相似文献
129.
Aiping Bai Zdzislaw M. Szulc Jacek Bielawski Nalini Mayroo Xiang Liu James Norris Yusuf A. Hannun Alicja Bielawska 《Bioorganic & medicinal chemistry》2009,17(5):1840-1848
Novel ω-N-amino analogs of B13 (Class E) were designed, synthesized and tested as inhibitors of acid ceramidase (ACDase) and potential anticancer agents deprived of unwanted lysosomal destabilization and ACDase proteolytic degradation properties of LCL204 [Szulc, Z. M.; Mayroo, N.; Bai, A.; Bielawski, J.; Liu, X.; Norris, J. S.; Hannun, Y. A.; Bielawska, A. Bioorg. Med. Chem. 2008, 16, 1015].Representative analog LCL464, (1R,2R)-2-N-(12′-N,N-dimethylaminododecanoyl amino)-1-(4″-nitrophenyl)-1,3-propandiol, inhibited ACDase activity in vitro, with a similar potency as B13 but higher than LCL204. LCL464 caused an early inhibition of this enzyme at a cellular level corresponding to decrease of sphingosine and specific increase of C14- and C16-ceramide. LCL464 did not induce lysosomal destabilization nor degradation of ACDase, showed increased cell death demonstrating inherent anticancer activity in a wide range of different cancer cell lines, and induction of apoptosis via executioner caspases activation. LCL464 represents a novel structural lead as chemotherapeutic agent acting via the inhibition of ACDase. 相似文献
130.
Diffusive Movement of Processive Kinesin-1 on Microtubules 总被引:1,自引:0,他引:1
Hailong Lu M. Yusuf Ali Carol S. Bookwalter David M. Warshaw Kathleen M. Trybus 《Traffic (Copenhagen, Denmark)》2009,10(10):1429-1438
The processive motor kinesin-1 moves unidirectionally toward the plus end of microtubules. This process can be visualized by total internal reflection fluorescence microscopy of kinesin bound to a carboxylated quantum dot (Qdot), which acts both as cargo and label. Surprisingly, when kinesin is bound to an anti-HIS Qdot, it shows diffusive movement on microtubules, which decreased in favor of processive runs with increasing salt concentration. This observation implies that kinesin movement on microtubules is governed by its conformation, as it is well established that kinesin undergoes a salt-dependent transition from a folded (inactive) to an extended (active) molecule. A truncated kinesin lacking the last 75 amino acids (kinesin-ΔC) showed both processive and diffusive movement on microtubules. The extent of each behavior depends on the relative amounts of ADP and ATP, with purely diffusive movement occurring in ADP alone. Taken together, these data imply that folded kinesin.ADP can exist in a state that diffuses along the microtubule lattice without expending energy. This mechanism may facilitate the ability of kinesin to pick up cargo, and/or allow the kinesin/cargo complex to stay bound after encountering obstacles. 相似文献