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111.
García-Mayoral MF Hollingworth D Masino L Díaz-Moreno I Kelly G Gherzi R Chou CF Chen CY Ramos A 《Structure (London, England : 1993)》2007,15(4):485-498
The AU-rich element (ARE) RNA-binding protein KSRP (K-homology splicing regulator protein) contains four KH domains and promotes the degradation of specific mRNAs that encode proteins with functions in cellular proliferation and inflammatory response. The fourth KH domain (KH4) is essential for mRNA recognition and decay but requires the third KH domain (KH3) for its function. We show that KH3 and KH4 behave as independent binding modules and can interact with different regions of the AU-rich RNA targets of KSRP. This provides KSRP with the structural flexibility needed to recognize a set of different targets in the context of their 3'UTR structural settings. Surprisingly, we find that KH4 binds to its target AREs with lower affinity than KH3 and that KSRP's mRNA binding, and mRNA degradation activities are closely associated with a conserved structural element of KH4. 相似文献
112.
The Mediterranean fruit fly (medfly), Ceratitis capitata (Wiedemann), is a key pest of citrus in Spain because of significant yield losses and to quarantine restrictions. Biologically based control methods, such as the Sterile Insect Technique (SIT), which relies on the sterilization by irradiation of large numbers of insects, is gaining an increasing role in the control of medfly in Mediterranean areas. However, gamma-irradiation might damage the midgut epithelium cells, causing a lowering of nutritive assimilation that can negatively affect adult performance. Irradiation effects on digestive physiology are well established for a number of insect pests, but there is no information on medfly. Our aim was to determine the effects of gamma-irradiation on C. capitata digestive protease activity. Both larvae and adults were found to use a similar proteolytic system based on aspartyl-, trypsin-, chymotrypsin-, amino peptidase-, and carboxypeptidase A- and B-like activities. Pupae of the Vienna-7 (tsl) strain were irradiated at 70 or 140 Gy, two days before emergence, and the adults fed during 5 days on sugar-protein (4:1) diets. Protease activity was measured in midgut extracts and compared with males non-irradiated reared in the same conditions. The results showed that the irradiation doses tested had no effect on the digestive proteolytic activities of medfly adults. Moreover, the longevity of irradiated medflies at the highest dose (140 Gy) was similar to that of controls. 相似文献
113.
AIDS is the result of a constant struggle between the lentivirus HIV and the immune system. Infection with HIV interferes directly with the function of CD4(+) T cells and manipulates the host immune response to the virus. Recent studies indicate that the viral protein Nef, a central player in HIV pathogenesis, impairs the ability of infected lymphocytes to form immunological synapses with antigen-presenting cells and affects T-cell-receptor-mediated stimulation. An integrative picture of the abnormal behaviour of HIV-infected lymphocytes is therefore emerging. We propose that modulating lymphocyte signalling, apoptosis and intracellular trafficking ensures efficient spread of the virus in the hostile environment of the immune system. 相似文献
114.
Structural and functional analyses of methyl-lysine binding by the malignant brain tumour repeat protein Sex comb on midleg 总被引:2,自引:0,他引:2
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Grimm C de Ayala Alonso AG Rybin V Steuerwald U Ly-Hartig N Fischle W Müller J Müller CW 《EMBO reports》2007,8(11):1031-1037
Sex comb on midleg (Scm) is a member of the Polycomb group of proteins involved in the maintenance of repression of Hox and other developmental control genes in Drosophila. The two malignant brain tumour (MBT) repeats of Scm form a domain that preferentially binds to monomethylated lysine residues either as a free amino acid or in the context of peptides, while unmodified or di- or trimethylated lysine residues are bound with significantly lower affinity. The crystal structure of a monomethyl-lysine-containing histone tail peptide bound to the MBT repeat domain shows that the methyl-lysine side chain occupies a binding pocket in the second MBT repeat formed by three conserved aromatic residues and one aspartate. Insertion of the monomethylated side chain into this pocket seems to be the main contributor to the binding affinity. Functional analyses in Drosophila show that the MBT domain of Scm and its methyl-lysine-binding activity are required for repression of Hox genes. 相似文献
115.
Sotiris Pavlopoulos Trias Thireou George Kontaxakis Andres Santos 《Biomedical engineering online》2007,6(1):36
Background
Dynamic positron emission tomography studies produce a large amount of image data, from which clinically useful parametric information can be extracted using tracer kinetic methods. Data reduction methods can facilitate the initial interpretation and visual analysis of these large image sequences and at the same time can preserve important information and allow for basic feature characterization. 相似文献116.
Furlan Lopes Cassiane Lemos Costa Alice Dionísio Jaqueline Fernanda Delgado Cañedo Andres da Rosa Renata Del Valle Garnero Analia Inacio Ribeiro José Ricardo Gunski Ricardo José 《Genetica》2022,150(5):235-246
Genetica - Known as "electric-light bugs", belostomatids potentially act as agents of biological control. The Belostoma genus has holokinetic chromosomes, interspecific variation in... 相似文献
117.
Jacomijn P. Dijksterhuis Bolormaa Baljinnyam Karen Stanger Hakki O. Sercan Yun Ji Osler Andres Jeffrey S. Rubin Rami N. Hannoush Gunnar Schulte 《The Journal of biological chemistry》2015,290(11):6789-6798
The seven-transmembrane-spanning receptors of the FZD1–10 class are bound and activated by the WNT family of lipoglycoproteins, thereby inducing a complex network of signaling pathways. However, the specificity of the interaction between mammalian WNT and FZD proteins and the subsequent signaling cascade downstream of the different WNT-FZD pairs have not been systematically addressed to date. In this study, we determined the binding affinities of various WNTs for different members of the FZD family by using bio-layer interferometry and characterized their functional selectivity in a cell system. Using purified WNTs, we show that different FZD cysteine-rich domains prefer to bind to distinct WNTs with fast on-rates and slow off-rates. In a 32D cell-based system engineered to overexpress FZD2, FZD4, or FZD5, we found that WNT-3A (but not WNT-4, -5A, or -9B) activated the WNT-β-catenin pathway through FZD2/4/5 as measured by phosphorylation of LRP6 and β-catenin stabilization. Surprisingly, different WNT-FZD pairs showed differential effects on phosphorylation of DVL2 and DVL3, revealing a previously unappreciated DVL isoform selectivity by different WNT-FZD pairs in 32D cells. In summary, we present extensive mapping of WNT-FZD cysteine-rich domain interactions complemented by analysis of WNT-FZD pair functionality in a unique cell system expressing individual FZD isoforms. Differential WNT-FZD binding and selective functional readouts suggest that endogenous WNT ligands evolved with an intrinsic natural bias toward different downstream signaling pathways, a phenomenon that could be of great importance in the design of FZD-targeting drugs. 相似文献
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