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排序方式: 共有251条查询结果,搜索用时 93 毫秒
31.
In this paper we have defined proteome signatures of Bacillus subtilis in response to heat, salt, peroxide, and superoxide stress as well as after starvation for ammonium, tryptophan, glucose, and phosphate using the 2-D gel-based approach. In total, 79 stress-induced and 155 starvation-induced marker proteins were identified including 50% that are not expressed in the vegetative proteome. Fused proteome maps and a color coding approach have been used to define stress-specific regulons that are involved in specific adaptative functions (HrcA for heat, PerR and Fur for oxidative stress, RecA for peroxide, CymR and S-box for superoxide stress). In addition, starvation-specific regulons are defined that are involved in the uptake or utilization of alternative nutrient sources (TnrA, sigmaL/BkdR for ammonium; tryptophan-activated RNA-binding attenuation protein for tryptophan; CcpA, CcpN, sigmaL/AcoR for glucose; PhoPR for phosphate starvation). The general stress or starvation proteome signatures include the CtsR, Spx, sigmaL/RocR, sigmaB, sigmaH, CodY, sigmaF, and sigmaE regulons. Among these, the Spx-dependent oxidase NfrA was induced by all stress conditions indicating stress-induced protein damages. Finally, a subset of sigmaH-dependent proteins (sporulation response regulator, YvyD, YtxH, YisK, YuxI, YpiB) and the CodY-dependent aspartyl phosphatase RapA were defined as general starvation proteins that indicate the transition to stationary phase caused by starvation. 相似文献
32.
David L. Cowles Jaclyn R. Van Dolson Lisa R. Hainey Dallas M. Dick 《Journal of experimental marine biology and ecology》2006,330(2):528-534
A behavioral assay was used to assess the ability of the stomatopod Hemisquilla californiensis to perceive and respond to a moving target under different wavelengths and intensities of light illumination. Subjects responded to targets rotating horizontally across their visual field by a brief startle response of their eyes or antennules but did not track the targets. Under white light responses were elicited down to a light intensity of 0.9 μW cm− 2. Responses were seen in blue light at intensities as low as 0.5 μW cm− 2, and in green light down to 1.0 μW cm− 2. The animals were less sensitive to red light, with no responses seen at intensities below 3.0 μW cm− 2. Subjects did not respond to the targets at all under infrared light. This response pattern mirrors the computed sensitivity spectrum of ommatidia in the species' peripheral hemispheres but not that in most of the central bands. We conclude that this species uses the monochromatic vision in the peripheral hemispheres of its eyes to recognize objects and that the sharply tuned color receptors of the central band serve to add supplemental information if light conditions allow. 相似文献
33.
The decolorization kinetics of Remazol Brilliant Violet 5R (RBV-5R) and Remazol Black B (RB-B) (mono- and diazo reactive dyes, respectively) was investigated in the first 9 h (anaerobic phase) of a 24-h cycle anaerobic/aerobic sequencing batch reactor (SBR). Two distinct, successive decolorization periods were observed for both dyes, apparently due to different decolorization mechanisms. The apparent first-order rate constants were much lower for the second periods. First-order kinetics were apparently followed for both periods of RBV-5R but not for the first decolorization period of RB-B, possibly due to the occurrence of mass transfer limitations. 相似文献
34.
Orange petals of calendula (Calendula officinalis) accumulate red carotenoids with the cis-configuration at the C-5 or C-5' position (5-cis-carotenoids). We speculated that the orange-flowered calendula is a carotenoid isomerase (crtiso) loss-of-function mutant that impairs the cis-to-trans conversion of 5-cis-carotenoids. We compared the sequences and enzyme activities of CRTISO from orange- and yellow-flowered calendulas. Four types of CRTISO were expressed in calendula petals. The deduced amino acid sequence of one of these genes (CoCRTISO1) was different between orange- and yellow-flowered calendulas, whereas the sequences of the other three CRTISOs were identical between these plants. Analysis of the enzymatic activities of the CoCRTISO homologs showed that CoCRTISO1-Y, which was expressed in yellow petals, converted carotenoids from the cis-to-trans-configuration, whereas both CoCRTISO1-ORa and 1-ORb, which were expressed in orange petals, showed no activity with any of the cis-carotenoids we tested. Moreover, the CoCRTISO1 genotypes of the F2 progeny obtained by crossing orange and yellow lines linked closely to petal color. These data indicate that CoCRTISO1 is a key regulator of the accumulation of 5-cis-carotenoids in calendula petals. Site-directed mutagenesis showed that the deletion of Cys-His-His at positions 462-464 in CoCRTISO1-ORa and a Gly-to-Glu amino acid substitution at position 450 in CoCRTISO1-ORb abolished enzyme activity completely, indicating that these amino acid residues are important for the enzymatic activity of CRTISO. 相似文献
35.
目的:探讨应用彩超在肾脏恶性肿瘤诊断及治疗中的应用效果。方法:回顾分析2006年1月~2010年12月在我院采用彩超确诊的肾脏恶性肿瘤138例,所有患者均采用LOGIQ-7彩色多普勒超声诊断仪进行检测并行手术治疗,术后均行病理检查。结果:138例患者彩超影像显示瘤体内具有丰富的动静脉血流信号,诊断为肾脏恶性肿瘤,与病理诊断完全相符。结论:彩超检查可以明确肾脏肿瘤的性质和范围,以供临床决定手术方式,也可用于术后复查。 相似文献
36.
Although camouflage is a common predator defense strategy across a wide variety of organisms, direct tests of the adaptive
and ecological consequences of camouflage are rare. In this study, we demonstrated that closely related crabs in the family
Epialtidae coexist in the same algal environment but use alternative forms of camouflage––decoration and color change––to
protect themselves from predation. Decoration and color change are both plastic camouflage strategies in that they can be
changed to match different habitats: decoration occurs on a short timescale (hours to days), while color change accompanies
molting and occurs on longer timescales (months). We found that the species that decorated the most had the lowest magnitude
of color change (Pugettia richii); the species that decorated the least showed the highest magnitude of color change (Pugettia producta), and a third species (Mimulus foliatus) was intermediate in both decoration and color change, suggesting a negative correlation in utilization of these strategies.
This negative correlation between color change and decoration camouflage utilization mirrored the effectiveness of these camouflage
strategies in reducing predation in different species. Color camouflage primarily reduced predation on P. producta, while decoration camouflage (but not color camouflage) reduced predation on P. richii. These results indicate there might be among-species trade-offs in utilization and/or effectiveness of these two forms of
plastic camouflage, with important consequences for distribution of these species among habitats and the evolution of different
camouflage strategies in this group. 相似文献
37.
Jinfeng Wang Pu Xu Jianyi Zhu Wei Zhou Jianrong Xu Xiugeng Fei Xuecheng Zhang 《Journal of applied phycology》2008,20(5):499-504
The color mutations in Bangiaceae were investigated by treating the blades, conchocelis and conchospores phase of Bangia sp., Porphyra yezoensis, and P. haitanensis sampled in China with mutagen N-methyl-N′-nitro-N-nitrosoguanidine (MNNG). A high percentage of mutation in different expression
characteristics in all three phases were shown within optimum mutagen concentrations. Among mutagenized blades, mutations
occurred on single cells, which is a direct outcome of mutation of haploid cells. The mutation of mutagenized conchocelis
resulted in a two-step process: low-level expression in conchocelis phase, and high-level expression in progeny, explaining
that mutation took place in diploid cells. The mutations of conchospores were expressed immediately at germination of spores,
indicating a change in ploidy. This paper reports the process of meiosis and its effect on frond development, and the relation
between color mutations and morphological characteristics expressed by mutations in Bangiaceae. 相似文献
38.
彩色多普勒超声对原位肝移植术后血流动力学研究 总被引:1,自引:1,他引:0
目的:探讨彩色多普勒超声(CDI)在原位肝移植术后对移植肝血流动力学变化的诊断价值。方法:应用CDI连续观察6例原位肝移植患者移植肝脏形态学变化,肝动脉峰值流速(HAmax)、门静脉及肝静脉平均流速(PVmean,HVmean)等指标,并以30例健康成人男性肝脏的血流动力学参数作为正常对照组。结果:在术后2周内肝脏移植组的HAmax低于正常对照组,1周内表现更为明显;术后1周内移植肝脏组的PVmean高于正常对照组,1周后表现不明显;移植肝脏组的Hvmean与正常对照组相比无明显差异。2周后,HA、PV和HV的血流速度基本上趋于正常。结论:CDI技术对了解肝移植术后移植肝的灌注情况,及早发现肝移植术后早期的并发症有重要意义。 相似文献
39.
Arikawa K. 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》2003,189(11):791-800
Journal of Comparative Physiology A - This review outlines our recent studies on the spectral organization of butterfly compound eyes, with emphasis on the Japanese yellow swallowtail butterfly,... 相似文献
40.
Analysis of Petal Anthocyanins to Investigate Flower Coloration of Zhongyuan (Chinese) and Daikon Island (Japanese) Tree Peony Cultivars 总被引:14,自引:0,他引:14
Liang-Sheng Wang Aya Shiraishi Fumio Hashimoto Noriaki Aoki Keiichi Shimizu Yusuke Sakata 《Journal of plant research》2001,114(1):33-43
Pn, Pg; Pn, Pg > Cy ; Pn, Cy and Pn, Cy > Pg groups. Each group consequently specified significant features among CIELAB color notation and petal pigmentation, being
adequate to characterize tree peony flowers as similar between Zhongyuan and Daikon Island cultivars, thus the cultivars of
the two areas are suggested to be related to one another.
Received 25 April 2000/ Accepted in revised form 21 December 2000 相似文献