全文获取类型
收费全文 | 1299篇 |
免费 | 69篇 |
国内免费 | 2篇 |
出版年
2022年 | 13篇 |
2021年 | 23篇 |
2020年 | 21篇 |
2019年 | 17篇 |
2018年 | 40篇 |
2017年 | 30篇 |
2016年 | 47篇 |
2015年 | 65篇 |
2014年 | 74篇 |
2013年 | 85篇 |
2012年 | 89篇 |
2011年 | 126篇 |
2010年 | 56篇 |
2009年 | 51篇 |
2008年 | 83篇 |
2007年 | 87篇 |
2006年 | 106篇 |
2005年 | 54篇 |
2004年 | 70篇 |
2003年 | 62篇 |
2002年 | 41篇 |
2001年 | 9篇 |
2000年 | 6篇 |
1999年 | 10篇 |
1998年 | 8篇 |
1997年 | 10篇 |
1996年 | 4篇 |
1995年 | 6篇 |
1993年 | 2篇 |
1992年 | 2篇 |
1991年 | 6篇 |
1990年 | 4篇 |
1989年 | 4篇 |
1988年 | 6篇 |
1987年 | 5篇 |
1986年 | 3篇 |
1985年 | 5篇 |
1984年 | 3篇 |
1983年 | 3篇 |
1982年 | 2篇 |
1981年 | 2篇 |
1979年 | 2篇 |
1978年 | 3篇 |
1977年 | 4篇 |
1976年 | 2篇 |
1974年 | 2篇 |
1973年 | 3篇 |
1972年 | 2篇 |
1970年 | 2篇 |
1969年 | 4篇 |
排序方式: 共有1370条查询结果,搜索用时 15 毫秒
1.
2.
3.
Jacek Kęsy Beata Maciejewska Magdalena Sowa Magdalena Szumilak Krzysztof Kawałowski Maja Borzuchowska Jan Kopcewicz 《Plant Growth Regulation》2008,55(1):43-50
It has been shown that both IAA and ethylene application inhibit flower induction in the short-day plant Pharbitis nil. However application of IAA has elevated ethylene production in this plant, as well. Strong enhancement of ethylene production
is also correlated with the night-break effect, which completely inhibits flowering. In order to determine what the role of
IAA and ethylene is in the photoperiodic flower induction in Pharbitis nil, we measured changes in their levels during inductive and non-inductive photoperiods, and the effects of ethylene biosynthesis
and action inhibitors on inhibition of flowering by IAA. Our results have shown that the inhibitory effect of IAA on Pharbitis nil flowering is not physiological but is connected with its effect on ethylene biosynthesis. 相似文献
4.
The influence of a single dose of ACTH(100 I.U. /kg body weight) on the diurnal rhythm of reduced glutathione (GSH) was studied in the blood and brain, liver and kidney homogenates of male mice. Cosinor analysis revealed that ACTH induces changes in the mean diurnal amount of GSH in the blood, brain, liver and kidneys. At the same time, GSH amplitudes in the blood and kidneys increased significantly, whereas in the case of brain and liver they decreased markedly. Moreover, it was found that ACTH induces a shift in GSH acrophases in the blood, brain, liver and kidneys as compared with the control values. 相似文献
5.
Beata Bartodziejska Joanna Radziejewska-Lebrecht Maria Lipinska Yuriy A. Knirel Leonid O. Kononov Anatoly Y. Chernyak Hubert Mayer Antoni Rozalski 《FEMS immunology and medical microbiology》1996,13(2):113-121
Abstract In DOC-PAGE, lipopolysaccharide (LPS) of Proteus mirabilis R14/1959 (Rb-type) mutant showed a ladder-like migration pattern indicating the presence of a high molecular weight polysaccharide chain. The isolated polysaccharide, called T-antigen because of similarity with the T1 chain of Salmonella friedenau LPS, contained d -glucose, d -galacturonic acid ( d -GalA), and d -GlcNAc in molar ratios 2:1:1 and was structurally different from the O-antigen of the parental S-strain P. mirabilis S1959 but identical to the O-antigen of another S-strain Proteus penneri 42. The importance of a d -GalA( l -Lys)-containing epitope, most likely present in the core region of LPS, and of GalA present in the T-antigen chain in manifesting the serological specificity of P. mirabilis R14/1959 were revealed using rabbit polyclonal homologous and heterologous R- and O-specific antisera and the appropriate antigens, including synthetic antigens which represent partial structures of various Proteus LPS. 相似文献
6.
Two series of amino-modified silicate gels prepared by sol-gel processing were used to absorb Cu(II), Ni(II), Co(II), Mn(II) and Cr(III) from aqueous solutions. These easily prepared sorbents with various content of primary amino groups in series (A) or primary and secondary amino groups in series (AA) have reasonable stability. The gel composition, time and concentration dependence of the uptake of the metal ions by these materials were studied systematically. These materials would be further used as supports to disperse catalytically active phases by conventional wet chemical procedures. Apart from this they demonstrate potential for the preconcentration aid for transition metal analysis. 相似文献
7.
The number of neurocytes containing lipofuscin pigment (LEP) was determined in the nucleus infundibularis dorsalis (NID), the subfornical organ (SFO) and the medulla oblongata (MO) of the brain of sexually mature females and males of Rana temporaria L. approximately identical in length and age. The frogs were captured in their natural habitat in seven periods of the annual cycle. The number of LFP-positive neurocytes shows distinct seasonal variations in the analyzed areas. In general, neurocytes containing LFP were found in higher numbers during the winter months, and their significant drop was observed in summer. The results seem to suggest that cells containing LFP represent a certain kind of dynamic cellular system responding to various internal and/or external factors changing within a year. 相似文献
8.
The influence of a single dose of actinomycin-D (1 mg/kg body weight) on the diurnal rhythm of cytoplasmic RNA was studied in neurocytes of the supraoptic nucleus (SON), paraventricular nucleus (PVN), and arcuate nucleus (AN) by microspectrophotometer. Cosinor analysis of the obtained results revealed a disturbed diurnal rhythm of cytoplasmic RNA in the animals treated with actinomycin-D. The mean diurnal RNA content in the SON, PVN, and AN neurocytes decreased, the amplitude of diurnal fluctuation was reduced and the acrophase was shifted to earlier hours. 相似文献
9.
W Dobryszycka B R Przysiecki E Krawczyk B Rudkowska 《Archives internationales de physiologie et de biochimie》1984,92(2):47-52
Inflammation was induced in rabbits by injection of turpentine or/and endotoxin. Haptoglobin (Hp) and lipoperoxide (as malondialdehyde - MDA) concentrations in rabbit plasma, were measured. In some experiments indomethacin was administered, as a specific control of anti-inflammatory action. In the course of the reagents-induced inflammation there existed positive correlation between changes in Hp and MDA levels. Indomethacin was found to eliminate this effect. Under the model system of experiments, Hp as presumed endogenous inhibitor of prostaglandin synthesis, even in concentrations in rabbits' blood 15-20 times higher than normal, did not exert any protective action against inflammation. 相似文献
10.
By the use of Mac Conaill's lead hematoxylin, periodic acid and Schiff's reagent (PAS, PbH-positive and PAS-positive cells were distinguished in the pars intermedia of the hypophysis in mice. Nuclear volume in PbH-positive and PAS-positive cells in the pars intermedia of the hypophysis in male and female mice under conditions of 12 h light and 12 h darkness shows distinct diurnal rhythmicity. Maximum nuclear volume in PbH-positive cells of the pars intermedia in both sexes was observed at 1800 h, and minimum at 2400 h. In the Pas-positive cells in females maximum nuclear volume was observed at 600 h, and minimum at 2400 h. In males maximal nuclear volume in these cells appears at 2400 h, and minimum at 1800 h. Maximum number of vacuoles in the nuclei of PbH-positive cells in the pars intermedia in both sexes appeared at 1800 h, and minimum at 2400 h. Maximum numbers of vacuoles in the nuclei of PAS-positive cells in females was noted at 1200 h, and minimum at 2400 h. In males the maximum number of vacuoles appeared at 600 h, and minimum at 1200 h. Differences in the number of vacuoles in the nuclei of PAS-positive cells between males and females were also noted. 相似文献