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61.
Efficient and selective recognition of DNA by proteins is due to sequence-specific interactions with a target site and nonselective electrostatic interactions that promote the target's rapid location. If synthetic molecules could mimic these functions, they would render a wide range of chromosome sequences accessible to rationally designed probes. Here we describe conjugates between bispeptide nucleic acids (bisPNAs) designed to specifically recognize duplex DNA and peptides that have been designed to promote rapid sequence recognition. Peptide design was based on the surface of staphylococcal nuclease, a cationic DNA binding protein with low sequence selectivity. We observe that attachment of the designed peptide increases rates of strand invasion by 100-fold relative to unmodified bisPNA. The peptide can contain D-amino acids, increasing the likelihood that it will be stable in cell extract and inside cells. Binding of the conjugate containing the D-amino acid peptide occurred over a broad range of experimental conditions and was sensitive to a single mismatch. Strand invasion was efficient at neutral to basic pH, a wide range of temperatures (0-65 degrees C), and in the presence of up to 7 mM Mg(2+) and 100 mM Na(+) or K(+). Our data suggest that attachment of peptides that mimic cationic protein surfaces to PNAs can afford conjugates that mimic the rapid and selective binding that characterizes native DNA binding proteins. Rapid strand invasion over a wide range of experimental conditions should further expand the utility of strand invasion by PNAs. 相似文献
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64.
Reconstruction of the weight-bearing surface of the foot with nonneurosensory free flaps 总被引:3,自引:0,他引:3
Sönmez A Bayramiçli M Sönmez B Numanoğlu A 《Plastic and reconstructive surgery》2003,111(7):2230-2236
Neurotized fasciocutaneous flaps and split-skin grafted muscle flaps are the most frequently used free flap alternatives for the reconstruction of weight-bearing surfaces of the foot. An objective comparison of the innate characteristics of these two flap types, with respect to long-term stability, has not been possible because sensory reinnervation in the fasciocutaneous flaps has been a confounding factor. This study compares nonsensate fasciocutaneous flaps (n = 9) with nonsensate split-skin grafted muscle flaps (n = 11), with mean follow-up periods of 34.3 and 31.3 months, respectively. Patients completed a form that included questions regarding degree of pain at the operative site, presence of ulcers, ability to wear normal shoes, employment status, and time spent standing on foot. Touch and deep sensation were evaluated with Semmes-Weinstein and vibration tests, respectively. Significantly less pain and less ulceration (p < 0.05) were observed in the fasciocutaneous group. Semmes-Weinstein monofilament tests revealed poorer results with split-skin grafted muscle flaps, compared with fasciocutaneous flaps. These results indicate that even if the sensory protection of fasciocutaneous flaps is not considered, these flaps have superior properties, compared with split-skin grafted muscle flaps. 相似文献
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The use of tissue expander base as an internal nasal splint 总被引:3,自引:0,他引:3
Eroğlu L Güneren E Akbaş H Demir A Karacalar A 《Plastic and reconstructive surgery》2003,111(2):942-943
68.
Baydar T Papp A Aydin A Nagymajtenyi L Schulz H Isimer A Sahin G 《Biological trace element research》2003,92(3):231-244
The present study was undertaken to examine possible aluminum (Al) accumulation in the brain of rats and to investigate whether
subchronic exposure to the metal leads to behavioral and neurophysiological changes in both treated and control groups. Each
of the groups consisted of 10 animals. Aluminum chloride (AlCl3) at a low (50 mg/kg/d) or high (200 mg/kg/d) dose was applied to male Wistar rats by gavage for 8 wk. Al-free water by gavage
was given to the control group throughout the experiment. Behavioral effects were evaluated by open-field (OF) motor activity
and by acoustic startle response (ASR). Electrophysiological examination was done by recording spontaneous activity and sensory-evoked
potentials from the visual, somatosensory, as well as auditory cortex. The Al content of each whole brain was determined by
electrothermal atomic absorption spectrophotometry. Subchronic Al exposure slightly caused some changes in the evoked potentials
and electrocorticograms and in the OF and ASR performance, but these results were not statistically significant. The brain
Al levels of the control and the low and high dose of Al-exposed groups were measured as 0.717±0.208 μg/g (wet weight), 0.963±0.491
μg/g (wet weight) and 1.816±1.157 μg/g (wet weight), respectively. 相似文献
69.
Oztürk A Baltaci AK Bediz CS Mogulkoc R Güngör S 《Biological trace element research》2003,96(1-3):255-262
The present study was designed to investigate the effects of zinc and/or melatonin deficiency on rat testes. A total of 24
adult male Sprague-Dawley rats were used in this study. The rats were divided into four groups of six rats each, as follows:
(I) controls, (II) zinc deficient, (III) pinealectomized, zinc normal, and (IV) pinealectomized, zinc deficient. The plasma
zinc levels in the control group were higher than in all the other groups (p<0.01), and those of the zinc-deficient groups II and IV were significantly lower than for group III (p<0.01). The melatonin levels in the controls were also significantly higher than for all other groups (p<0.01) There was no significant difference in sperm production between the controls and the group of animals that had no epiphysis.
A significant suppression was observed in the spermatogenetic activity of the zinc-deficient groups (p<0.01). The suppression was higher in group II than in group IV. These results indicate that testicular damage caused by zinc
deficiency may be reduced by melatonin deficiency. 相似文献
70.
Ozturk A Baltaci AK Mogulkoc R Oztekin E Sivrikaya A Kurtoglu E Kul A 《Biological trace element research》2003,94(2):157-166
The aim of the study was to investigate the effects of zinc deficiency and supplementation on lipid peroxidation and glutathione
levels in blood and in some tissues of rats performing swimming exercise. Forty adult male Sprague-Dawley rats were divided
into four groups: group 1, zinc-deficient consisted of swimming rats; group 2 consisted of zinc-supplemented swimming rats;
groups 3 and 4 were the swimming and nonswimming controls, respectively. The levels of malondialdehyde and glutathione were
measured after 4 wk of zinc-deficient or zinc-supplemented diet and 30 min of swimming exercise daily.
The erythrocyte glutathione levels of groups 2 and 4 were significantly higher than those of groups 1 and 3 (p<0.01). The plasma malondialdehyde level of group 1 was significantly higher than all other groups. The glutathione levels
in liver, kidney, striated muscle, and testes of group 2 were higher than in the other groups (p<0.01) and higher in kidney and striated muscle of group 3 than in groups 1 and 4 (p<0.01). The tissue malondialdehyde levels of striated muscle, liver, kidney, and testes of group 1 were significantly higher
than for all other groups (p<0.01). Our findings suggest that both swimming exercise and zinc deficiency result in an increase of lipid peroxidation in
tissues and that zinc supplementation prevents these alterations by the activation of the antioxidant system. 相似文献