全文获取类型
收费全文 | 108篇 |
免费 | 12篇 |
出版年
2022年 | 1篇 |
2021年 | 1篇 |
2020年 | 1篇 |
2019年 | 2篇 |
2018年 | 3篇 |
2017年 | 3篇 |
2016年 | 4篇 |
2015年 | 6篇 |
2014年 | 10篇 |
2013年 | 6篇 |
2012年 | 4篇 |
2011年 | 8篇 |
2010年 | 2篇 |
2009年 | 4篇 |
2008年 | 7篇 |
2007年 | 6篇 |
2006年 | 2篇 |
2005年 | 3篇 |
2004年 | 2篇 |
2003年 | 2篇 |
2002年 | 6篇 |
2001年 | 3篇 |
1999年 | 2篇 |
1998年 | 1篇 |
1997年 | 1篇 |
1991年 | 3篇 |
1989年 | 1篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1985年 | 4篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1978年 | 2篇 |
1976年 | 1篇 |
1975年 | 3篇 |
1974年 | 2篇 |
1972年 | 1篇 |
1969年 | 2篇 |
1968年 | 1篇 |
1966年 | 1篇 |
1962年 | 1篇 |
1960年 | 1篇 |
1955年 | 1篇 |
1953年 | 1篇 |
排序方式: 共有120条查询结果,搜索用时 0 毫秒
111.
A modification of Gomori's method for alkaline phosphatase was applied to 5-7 mm cubes of fresh, unfixed human skin. Exposure to the substrate of buffered Na-β·glycerophosphate was varied from 8-36 hr, to the 2% Co(NO3)3, 2-12 hr; and to ammonium sulfide (containing approximately 1% NH3), 1-2 hr. Optimum timing for these treatments were found to be 24, 4 and 1 hr, respectively. After staining, blocks were embedded in paraffin and serial sections were made. In such small blocks, the staining was uniform throughout the block. Alkaline phosphatase activity was seen in the walls of the subepidermal and periappendageal capillaries, as well as in the eccrine sweat glands, and did not differ from that seen in stained frozen sections. In particular, there was no loss of specificity and no diffusion of the enzyme. 相似文献
112.
S H el-Sharkaway M I Selim M S Afifi F T Halaweish 《Applied and environmental microbiology》1991,57(2):549-552
The conversion of zearalenone by various microorganisms was studied. A new polar metabolite was formed in addition to alpha- and beta-zearalenols. The structure of the new metabolite was determined as zearalenone-4-O-sulfate conjugate on the basis of enzymatic and acid hydrolysis, followed by mass spectrometry, nuclear magnetic resonance, and infrared spectroscopic analysis. The results obtained demonstrate that Rhizopus arrhizus catalyzes sulfation of zearalenone at the C-4 hydroxyl group. 相似文献
113.
Dennis V Pedersen Gregers R Andersen Dennis V Pedersen Lubka Roumenina Rasmus K Jensen Trine AF Gadeberg Chiara Marinozzi Capucine Picard Tania Rybkine Steffen Thiel Uffe BS Sørensen Cordula Stover Veronique Fremeaux-Bacchi Gregers R Andersen 《The EMBO journal》2017,36(8):1084-1099
Properdin (FP) is an essential positive regulator of the complement alternative pathway (AP) providing stabilization of the C3 and C5 convertases, but its oligomeric nature challenges structural analysis. We describe here a novel FP deficiency (E244K) caused by a single point mutation which results in a very low level of AP activity. Recombinant FP E244K is monomeric, fails to support bacteriolysis, and binds weakly to C3 products. We compare this to a monomeric unit excised from oligomeric FP, which is also dysfunctional in bacteriolysis but binds the AP proconvertase, C3 convertase, C3 products and partially stabilizes the convertase. The crystal structure of such a FP-convertase complex suggests that the major contact between FP and the AP convertase is mediated by a single FP thrombospondin repeat and a small region in C3b. Small angle X-ray scattering indicates that FP E244K is trapped in a compact conformation preventing its oligomerization. Our studies demonstrate an essential role of FP oligomerization in vivo while our monomers enable detailed structural insight paving the way for novel modulators of complement. 相似文献
114.
115.
116.
The effect of breed, year of production, age of doe at conception, season of conception and parity on doe's weight at conception, at the 1st, 2nd, 3rd and 4th week of gestation, after kindling and on doe's total weight gain during gestation were studied using data from 250 pregnant does from five breeds of rabbits: Bauscat, Giza White, Baladi Red, Gray Giant Flander and Baladi White. Breed and year of production were the most important factors affecting doe's weight during pregnancy and after kindling while the other factors were of minor influence. Age of doe at conception was not significant for all the weights and total weight gain recorded. Season of conception was the most important factor affecting doe's total weight gain during gestation while all the other factors were of minor importance. The effect of parity was significant for doe's weight at the 4th week of gestation, otherwise it was not significant for the weights and total weight gain recorded. Breed rank for doe's weight at different stages of gestation differed from that for doe's total weight gain during pregnancy. Weights and total weight gain of pregnant does recorded during 1978/79 were higher than those recorded during 1977/78. 相似文献
117.
W H Stork J A Van Boxsel A F De Goeij AF+DEGOEIJ P L De Haseth PL+DEHASETH M Mandel 《Biophysical chemistry》1974,2(2):127-136
Binding of auramine O to poly-(methacrylic acid) (PMA) has been established over a large range of C0p/C0d values using spectroscopic methods (UV absorption and visible fluorescence emission spectra), equilibrium and sedimentation dialysis, potentiometric and viscosimetric titrations. All the results show qualitative agreement with those obtained previously with the system crystal violet-PMA although the binding seems to be less strong for auramine O than for crystal violet. From dialysis experiments binding isotherms were obtained at three different degrees of neutralization α'; at α' = 0.10 the results could be fitted to a Langmuir isotherm but at α' equal to 0.40 and 0.65 deviations with respect to such an isotherm occur. The results of potentiometric and viscosimetric titrations confirm that the conformational transition which the dye-free PMA exhibits upon ionization is affected by the dye binding. The region in which the conformational transion occurs is broadened and is less sharply defined in the presence of auramine O. 相似文献
118.
119.
A non-significant buck effect on the number of services per conception, service period and litter size at birth in Bauscat rabbits was found using 66 bucks. The within-buck repeatability of number of services per conception and service period of 0.027 ± 0.028 and 0.035 ± 0.029, respectively, were non-significant. The same parameter for litter size at birth could not be obtained because of the negative buck component of variance observed. For this population of rabbits it appeared that no difference in these traits existed among bucks and, as a result, improvement in these traits could not be made by selection of bucks based on their own performance. 相似文献
120.
Evaluation of exact and asymptotic interval estimators in logistic analysis of matched case-control studies. 总被引:1,自引:0,他引:1
We compare six methods for constructing confidence intervals for a single parameter in stratified logistic regression. Three of these are based on inversion of standard asymptotic tests--namely, the Wald, the score, and the likelihood ratio tests. The other three are based on the exact distribution of the sufficient statistic for the parameter of interest. These include the traditional exact method of constructing confidence intervals, and two others, the mid-P and mean-P methods, which are modifications of this procedure that aim at reducing the conservative bias of the exact method. Using efficient algorithms, the six methods are compared by determination of their exact coverage levels in a series of conditional sample spaces. An incident case-control study of lung cancer in women is used to further illustrate the differences among the various methods. Computation of coverage functions is seen as a useful graphical diagnostic tool for assessing the appropriateness of different methods. The mid-P and the score methods are seen to have better coverage properties than the other four. 相似文献