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排序方式: 共有1932条查询结果,搜索用时 187 毫秒
71.
Kumura H Takagaki K Sone T Tsukahara M Tanaka T Shimazaki K 《Bioscience, biotechnology, and biochemistry》2002,66(6):1370-1373
To understand the possible proteolytic contribution of yeast during cheese ripening, Debaryomyces hansenii 212 was isolated from commercial blue-veined cheese and incubated in a medium containing casein. Growth and casein degradation were recognized at the cheese-ripening temperature. Proteolytic activity was found in the intracellular fraction, and the enzyme, which was attached to the cell wall, primarily acted on beta-casein. The cytosol contained more than 90% of the total proteolytic activity which was responsible for the degradation of both alpha(s)- and beta-casein. These results suggest that the contribution of yeast to cheese ripening would depend on the susceptibility to cell lysis in addition to its proteolytic activity. 相似文献
72.
Takao M Yamaguchi A Yoshikawa K Terashita T Sakai T 《Bioscience, biotechnology, and biochemistry》2002,66(2):430-433
The gene that encodes a thermostable endo-arabinase (called ABN-TS) from Bacillus thermodenitrificans TS-3 was cloned, sequenced, and expressed in the mesophilic B. subtilis. The gene contained an open reading frame consists of 939 bp, which encodes 313 amino acids. The deduced amino acid sequence of the enzyme showed 50, 46, and 36% similarity with endo-arabinase from B. subtilis IFO 3134 (PPase-C), Pseudomonas fluorescens (ArbA), and Aspergillus niger (ABNA), respectively. The hydrophobic and acidic amino acids making up ABN-TS outnumbered those in PPase-C. The gene product expressed in B. subtilis, as the host, had substantially the same characteristics, and was stable up to 70 degrees C, and the reaction was optimal around 70 degrees C, as well as native ABN-TS. 相似文献
73.
Sakai T Kato K Watanabe K Orii H 《The International journal of developmental biology》2002,46(3):329-332
The pharynx is a distinctive organ in the center of the body of planarians. Although the process of pharynx regeneration has been studied previously, the details and mechanism of the process remain controversial. We examined the process of regeneration of the pharynx in the planarian Dugesia japonica in detail by in situ hybridization and immunohistochemistry for myosin heavy chain-A (DjMHC-A), which is mainly expressed in the pharynx muscles and pharynx-anchoring muscles. We also monitored the behavior of the neoblasts in this process. In the regenerating posterior body fragment, the pharyngeal rudiment was formed by accumulation of cells that were probably undifferentiated cells derived from the neoblasts. The pharynx muscles appeared to differentiate in the rudiment in a manner that was coordinated with the differentiation of the pharynx-anchoring muscles in the region surrounding the rudiment. During this process, all cells containing mRNA for DjMHC-A also contained the DjMHC-A protein. These results argue against a previously proposed hypothesis that in the mesenchyme, 'pharynx-forming cells', which are committed to differentiate into the pharyngeal cells but have not yet differentiated, gather in the rudiment to form the pharynx (Agata and Watanabe, 1999). Rather, the present observations suggest that regeneration of the planarian pharynx proceeds by accumulation of cells that are probably undifferentiated cells derived from neoblasts in the rudiment, followed by their differentiation into the pharyngeal cells there. 相似文献
74.
The phase-resetting experiment was applied to human periodic finger tapping to understand how its rhythm is controlled by
the internal neural clock that is assumed to exist. In the experiment, the right periodic tapping movement was disturbed transiently
by a series of left finger taps in response to impulsive auditory cues presented randomly at various phases within the tapping
cycle. After each left finger tap, the original periodic tapping was reestablished within several tapping cycles. Influences
of the disturbance on the periodic right finger tapping varied depending on the phase of the periodic right finger tapping
at which each left finger tap was made. It was confirmed that the periodic tapping was disturbed not by the auditory cues
but by the left finger taps. Based on this fact, in this paper each single left tap was considered as the stimulus, and the
phase of the periodic tapping of the right index finger when the left tap was executed as the phase of the stimulus. Responses
of the neural activities (magnetoencephalography, MEG), the tapping movement, and the corresponding muscle activities (electromyography)
were simultaneously measured. Phase-resetting curves (PRCs) representing the degree of phase reset as a function of the phase
of the stimulus were obtained both for the left sensorimotor cortex MEG response and for the right index finger tapping response.
The shapes of both PRCs were similar, suggesting that the phase reset of the left sensorimotor cortex activities and that
of the finger tapping rhythm were the same. Four out of eight subjects showed type-0 reset in Winfree's definition, and the
others showed type-1 reset. For general limit-cycle oscillators, type-0 reset is obtained for relatively strong perturbations
and type 1 for weak perturbations. It was shown that the transient response of MEG to the single left tap stimuli in type-0
subjects, where the phase was progressively reset, were different from those in type-1 subjects. Based on detailed analysis
of the differences, a neural network model for the phase reset of the tapping rhythm is proposed.
Received: 10 February 2000 / Accepted in revised form: 15 January 2002 相似文献
75.
Conversion of gastric mucosa to intestinal metaplasia in Cdx2-expressing transgenic mice 总被引:23,自引:0,他引:23
Mutoh H Hakamata Y Sato K Eda A Yanaka I Honda S Osawa H Kaneko Y Sugano K 《Biochemical and biophysical research communications》2002,294(2):470-479
Gastric intestinal metaplasia occurs as a pathological condition in the gastric mucosa. To clarify how an intestine-specific homeobox gene, Cdx2, affects the morphogenesis of gastric mucosa, we generated transgenic mice expressing Cdx2 in parietal cells. Until Day 18 after birth, the number of parietal cells inthegastric mucosa of transgenic mice was the same as for their normal littermates. However, at Day 19, we detected several glands in which parietal cells disappeared and the proliferating zone moved from the isthmus to the base of the glands. Thereafter, parietal cells decreased gradually and disappeared at Day 37. All of the gastric mucosal cells, except for enterochromaffin-like (ECL) cells, were completely replaced by intestinal metaplasia, consisting of goblet cells, enteroendocrine cells, and absorptive cells expressing alkaline phosphatase. Pseudopyloric gland metaplasia was also formed. The transgenic mouse is a very useful model for clarifying physiological differentiation of gastric and intestinal cell lineages and analyzing the molecular events from intestinal metaplasia to adenocarcinoma. 相似文献
76.
Oikawa H Tun Z Young DR Ozawa H Yamazaki K Tanaka E Honda K 《Biochemical and biophysical research communications》2002,297(2):341-345
Hypervariable segments of mitochondrial DNA (mtDNA) (HV1 and HV2) were analyzed in Klinefelter's syndrome and compared to normal population data. One pair of samples consisting of a Japanese mother and affected son with Klinefelter's syndrome (involved in a criminal case), and seven unrelated DNA samples from Caucasian Klinefelter males (two involved in criminal cases and five diagnosed) were collected in Japan and the United States. The diagnosis of Klinefelter's syndrome was established previously by multiplex XY-STR typing detecting two X alleles and one Y allele in the samples. Haplotype analysis of the mtDNA sequence in Klinefelter males was found to be identical, unique, and specific, as it was not found in the normal population. Astonishingly, family data exhibited that the haplotype of the mtDNA in the son was apparently different from the mother's, suggesting that the mtDNA of Klinefelter male would not be inherited from mother to son. Our data indicate that possible interaction of the sex chromosome and the mtDNA exists, and suggests that the specific mtDNA haplotype could cause the abnormal cell to fertilize and reproduce itself. 相似文献
77.
Kentaro Nagamine Yoko Kuzuhara Tsugunori Notomi 《Biochemical and biophysical research communications》2002,290(4):1195-1198
Loop-mediated isothermal amplification (LAMP), in which a specific DNA sequence can be directly amplified under isothermal conditions, yields DNA in large quantities of more than 500 microg/ml. We have developed a method to isolate single-stranded DNA fragments from LAMP products that are stem-loop DNAs with several inverted repeats of the target DNA. This method requires the TspRI restriction enzyme, a primer hybridized to the 3' overhanging sequence at its cleavage site, and a DNA polymerase with strand displacement activity. The LAMP products are digested with TspRI and are then extended using the primer, producing the strand-specific DNA fragments. All processes, from LAMP reaction to primer extension, can be carried out at the same temperature. The use of strand-specific DNA would be conducive for detection by hybridization technique such as DNA microarrays. 相似文献
78.
79.
80.
Two lignan dimers from bamboo stems (Phyllostachys edulis) 总被引:2,自引:0,他引:2
Phyllostadimers A and B, two bis-lignans in which the two lignan units are directly connected by a C-C bond, were isolated from stems of bamboo, Phyllostachys edulis. Their structures were determined on the basis of spectral evidence. In addition, 14 known compounds were also obtained throughout the investigation. Phyllostadimer A significantly inhibited liposomal lipid peroxidation. 相似文献