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1.
2.
Compression wood (CW) contains higher quantities of β-1-4-galactan than does normal wood (NW). However, the physiological
roles and ultrastructural distribution of β-1-4-galactan during CW formation are still not well understood. The present work
investigated deposition of β-1-4-galactan in differentiating tracheids of Cryptomeria japonica during CW formation using an immunological probe (LM5) combined with immunomicroscopy. Our immunolabeling studies clearly
showed that differences in the distribution of β-1-4-galactan between NW (and opposite wood, OW) and CW are initiated during
the formation of the S1 layer. At this stage, CW was strongly labeled in the S1 layer, whereas no label was observed in the S1 layer of NW and OW. Immunogold labeling showed that β-1-4-galactan in the S1 layer of CW tracheids significantly decreased during the formation of the S2 layer. Most β-1-4-galactan labeling was present in the outer S2 region in mature CW tracheids, and was absent in the inner S2 layer that contained helical cavities in the cell wall. In addition, delignified CW tracheids showed significantly more labeling
of β-1-4-galactan in the secondary cell wall, suggesting that lignin is likely to mask β-1-4-galactan epitopes. The study
clearly showed that β-1-4-galactan in CW was mainly deposited in the outer portion of the secondary cell wall, indicating
that its distribution may be spatially consistent with lignin distribution in CW tracheids of Cryptomeria japonica. 相似文献
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Bacteriophages (or phages) play major roles in the evolution of bacterial pathogens via horizontal gene transfer. Multiple phages are often integrated in a host chromosome as prophages, not only carrying various novel virulence-related genetic determinants into host bacteria but also providing various possibilities for prophage-prophage interactions in bacterial cells. In particular, Escherichia coli strains such as Shiga toxin (Stx)-producing E. coli (STEC) and enteropathogenic E. coli (EPEC) strains have acquired more than 10 prophages (up to 21 prophages), many of which encode type III secretion system (T3SS) effector gene clusters. In these strains, some prophages are present at a single locus in tandem, which is usually interpreted as the integration of phages that use the same attachment (att) sequence. Here, we present phages integrating into T3SS effector gene cluster-associated loci in prophages, which are widely distributed in STEC and EPEC. Some of the phages integrated into prophages are Stx-encoding phages (Stx phages) and have induced the duplication of Stx phages in a single cell. The identified attB sequences in prophage genomes are apparently derived from host chromosomes. In addition, two or three different attB sequences are present in some prophages, which results in the generation of prophage clusters in various complex configurations. These phages integrating into prophages represent a medically and biologically important type of inter-phage interaction that promotes the accumulation of T3SS effector genes in STEC and EPEC, the duplication of Stx phages in STEC, and the conversion of EPEC to STEC and that may be distributed in other types of E. coli strains as well as other prophage-rich bacterial species. 相似文献
5.
Corynebacterium equi IFO 3730 was found to oxidize a wide variety of sec-alcohols, including alkanols, substituted alkanols, alkenols and cyclic alcohols, in moderate to high yields. Among them, the sec-alcohols which have longer carbon chains were oxidized more smoothly than those with smaller numbers of carbon. Although both enantiomers of unsymmetrically disubstituted carbinols were oxidized, the S form of 2-dodecanol was converted to the corresponding ketone a little faster than the other enantiomer. 相似文献
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Yosiaki Itô 《Journal of Ethology》1987,5(2):115-124
Social behaviour ofRopalidia revolutionalis (de Saussure) was observed in Brisbane and Townsville. Nests were, as a rule, founded by association of females. Each nest
began as a single comb but, after the emergence of progeny adults, satellite combs were constructed near the original comb.
During the pre-emergence (single-comb) stage, each colony had a single egg-layer, despite the rare occurrence of intranidal
dominance acts among female wasps. When colonies had reached the multiple-comb stage, the frequency and intensity of intranidal
dominance-aggressive acts rose to a high level, comparable to those of typically aggressive colonies of e.g.Polistes canadensis in Panama. Colonies appeared to be still functionally haplometrotic during the early phase of multiple-comb stage, but several
potential egg-layers were present as colony size increased. Dominant females often performed wing vibration, rapid runs between
combs and tended to sit on the largest comb, whilst subordinate females tended to sit on smaller combs. 相似文献
9.
C. R. Vonk E. Davelaar S. A. Ribôt B. Shadid H. C. Van der Plas 《Plant Growth Regulation》1989,8(3):263-276
It is shown that in bulbous Iris zeatin originates from a nucleotide. This nucleotide is probably zeatin-allylic-phosphate, in which a phosphate group is attached to the isoprenoid side-chain of zeatin. The formation of zeatin-allylic-phosphate from t-zeatin and 8-[14C]-zeatin by the microsomal fractions of Iris bulb disks and Helianthus tubers was demonstrated. The responsible enzyme was partially purified. 5-AMP was found to be a phosphate group delivering substrate. Adenosine and adenine inhibited the enzyme reaction. The significance of the results is discussed in relation to cytokinin biosynthesis and the occurrence of bud blast in Iris. 相似文献
10.
Keiji Sugimoto Sachiko Fujii Masayoshi Kaiho Itsuo Nakamura 《Cell and tissue research》1990,261(3):509-516
Summary Actin-containing cytoplasmic fibers were visualized in the mesenteric mesothelial cells of the large intestine of bullfrog tadpoles by rhodamine-phalloidin staining of en face preparations of mesothelial cells. These fibers were concurrently stained by immunofluorescence using antibodies to myosin or -actinin. Electron microscopy showed the presence of bundles of microfilaments in the basal cytoplasm of the cells. Such fibers in the mesothelial cells may be comparable to the stress fibers present in cultured cells. The mesothelial cells initially formed axially oriented stress fibers when they changed from a rhombic to a slender spindle-like shape. On the other hand, stress fibers disappeared as cells transformed from elongated to polygonal shapes during the period of metamorphic climax. Expression of stress fibers in these cells appears to be related to the degree of tension loaded on the mesentery, which may be generated by mesenteric winding. These stress fibers in the mesothelial cells may serve to regulate cellular transformation. They may also help to maintain cellular integrity by strengthening the cellular attachment to subepithelial tissue against tensile stress exerted on the mesentery. 相似文献