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Plant polyphenols, especially flavonoids, are active and pro‐health substances found in fruits and vegetables. Quercetin and its glycoside rutin are representatives of flavonoids, commonly found in plant products. Catechins found in large quantities in tea are also a well‐known group of natural polyphenols. These compounds are based on the structure of flavan‐3‐ol, which is why the number, positions and types of substitutions affect the scavenging of radicals and other properties. Despite some inconsistent evidence, several structure?activity relationships of monomeric flavonoids are well established in vitro. However, the relationships between the activity and other properties of the polymeric forms of flavonoids and their structures are poorly understood so far. The aim of this article is to compare the data on polymerization of quercetin, rutin and catechin, as well as to systematize knowledge about the structure?activity relationship of the polymeric forms of these compounds. 相似文献
44.
Wojciech Lipinski Joanna Wasko Malgorzata Walczak Justyna Fraczyk Zbigniew J. Kaminski Krystian Galecki Zbigniew Draczynski Izabella Krucinska Marta Kaminska Beata Kolesinska 《化学与生物多样性》2019,16(11)
The aim of the study was the assessment of the ability of short peptides to form aggregates under physiological conditions. The dipeptides studied were derived from different aromatic amino acids (heteroaromatic peptides). Tripeptides were obtained from two distinct aromatic amino acids and cysteine or methionine residue in the C‐terminal, N‐terminal, or central position. The ability of the peptides to form fibrous aggregates under physiological conditions was evaluated using three independent methods: the Congo Red assay, the Thioflavin T assay, and microscopic examinations using normal and polarized light. Materials potentially useful for regenerative medicine were selected based on their cytotoxicity to the endothelial cell line EA.hy 926 and physicochemical properties of films formed by peptides. The required parameters of biocompatibility were fulfilled by H?PheCysTrp?OH, H?PheCysTyr?OH, H?PheTyrMet?OH, and H?TrpTyr?OH. 相似文献
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Hybridization in large-bodied New World primates 总被引:2,自引:0,他引:2
Cortés-Ortiz L Duda TF Canales-Espinosa D García-Orduña F Rodríguez-Luna E Bermingham E 《Genetics》2007,176(4):2421-2425
Well-documented cases of natural hybridization among primates are not common. In New World primates, natural hybridization has been reported only for small-bodied species, but no genotypic data have ever been gathered that confirm these reports. Here we present genetic evidence of hybridization of two large-bodied species of neotropical primates that diverged approximately 3 MYA. We used species-diagnostic mitochondrial and microsatellite loci and the Y chromosome Sry gene to determine the hybrid status of 36 individuals collected from an area of sympatry in Tabasco, Mexico. Thirteen individuals were hybrids. We show that hybridization and subsequent backcrosses are directionally biased and that the only likely cross between parental species produces fertile hybrid females, but fails to produce viable or fertile males. This system can be used as a model to study gene interchange between primate species that have not achieved complete reproductive isolation. 相似文献
48.
Identification of mutations that decrease the stability of a fragment of Saccharomyces cerevisiae chromosome III lacking efficient replicators 总被引:1,自引:0,他引:1
Theis JF Dershowitz A Irene C Maciariello C Tobin ML Liberi G Tabrizifard S Korus M Fabiani L Newlon CS 《Genetics》2007,177(3):1445-1458
Eukaryotic chromosomes are duplicated during S phase and transmitted to progeny during mitosis with high fidelity. Chromosome duplication is controlled at the level of replication initiation, which occurs at cis-acting replicator sequences that are spaced at intervals of approximately 40 kb along the chromosomes of the budding yeast Saccharomyces cerevisiae. Surprisingly, we found that derivatives of yeast chromosome III that lack known replicators were replicated and segregated properly in at least 96% of cell divisions. To gain insight into the mechanisms that maintain these "originless" chromosome fragments, we screened for mutants defective in the maintenance of an "originless" chromosome fragment, but proficient in the maintenance of the same fragment that carries its normal complement of replicators (originless fragment maintenance mutants, or ofm). We show that three of these Ofm mutations appear to disrupt different processes involved in chromosome transmission. The OFM1-1 mutant seems to disrupt an alternative initiation mechanism, and the ofm6 mutant appears to be defective in replication fork progression. ofm14 is an allele of RAD9, which is required for the activation of the DNA damage checkpoint, suggesting that this checkpoint plays a key role in the maintenance of the "originless" fragment. 相似文献
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Gene expression dynamics in deer antler: mesenchymal differentiation toward chondrogenesis 总被引:6,自引:0,他引:6
Gyurján I Molnár A Borsy A Stéger V Hackler L Zomborszky Z Papp P Duda E Deák F Lakatos P Puskás LG Orosz L 《Molecular genetics and genomics : MGG》2007,277(3):221-235
Annual re-growth of deer antler represents a unique example of complete organ regeneration. Because antler mesenchymal cells
retain their embryonic capacity to develop into cartilage or bone, studying antler development provides a natural system to
follow gene expression changes during mesenchymal differentiation toward chondrogenic/osteogenic lineage. To identify novel
genes involved either in early events of mesenchymal cell specialization or in robust bone development, we have introduced
a 3 K heterologous microarray set-up (deer cDNA versus mouse template). Fifteen genes were differentially expressed; genes
for housekeeping, regulatory functions (components of different signaling pathways, including FGF, TGFβ, Wnt), and genes encoding
members of the Polycomb group were represented. Expression dynamics for genes are visualized by an expression logo. The expression
profile of the gene C21orf70 of unknown function is described along with the effects when over-expressed; furthermore the nuclear localization of the
cognate protein is shown. In this report, we demonstrate the particular advantage of the velvet antler model in bone research
for: (1) identification of mesenchymal and precartilaginous genes and (2) targeting genes upregulated in robust cartilage
development.
Electronic supplementary material Supplementary material is available in the online version of this article at and is accessible for authorized users. 相似文献
50.
Regulation of autophagy in bovine mammary epithelial cells 总被引:1,自引:0,他引:1
The bovine mammary gland undergoes intensive remodelling during the lactation cycle, and the escalation of this process is observed during dry periods. The main type of cell death responsible for bovine mammary gland involution is apoptosis; however, there are also a lot of cells exhibiting morphological features of autophagy during drying off. Our in vitro and in vivo studies of bovine mammary gland physiology suggest that the enhanced process of autophagy, observed at the end of lactation and during dry periods, is the result of: (1) decreased level of lactogenic hormones (GH, IGF-I), (2) decreased GH-R and IGF-IR alpha expression, (3) increased expression of auto/paracrine apoptogenic peptides (IGFBPs, TGFbeta), (4) increased influence of sex steroids (17beta-estradiol and progesterone) and (5) enhanced competition between the between the intensively developing fetus and the mother organism for nutritional and bioactive compounds. The above conditions may create a state of temporary malnutrition of mammary epithelial cells, which forces the cells to the induction of autophagy, as a mechanism for stabilizing intracellular supplies of energy and amino acids, especially during the enhanced activity of apoptogenic factors. 相似文献