The phrase "are many significant differences" is correct and usable in written English.
You can use it when discussing or comparing two or more subjects to highlight the notable distinctions between them.
Example: "When examining the two theories, it becomes clear that there are many significant differences in their underlying principles."
Alternatives: "exist numerous important differences" or "have several key differences".
George Rupp, Columbia's president, criticized the decision, saying, "There are many significant differences between graduate education at Columbia and N.Y.U".
There are many significant differences between the wars in Vietnam and in Iraq - a point that senior Bush administration officials make at any opportunity.
However, there are many significant differences between petroleum and environmental applications of surfactants, so many new features have been added to model contaminant transport and remediation and these are described and illustrated for the first time here.
The recent development of intact lipid profiling of lipids from dried blood spot samples has allowed us to investigate the effect of diet on the lipid metabolism of infants and we have shown that there are many significant differences in the lipid metabolism between breast-fed infants and formula-fed infants.
Whilst Bowlby's early writings on maternal deprivation may be seen as part of the background to the later development of attachment theory, there are many significant differences between the two.
First, when the absolute gene expression levels are compared between LCM and bulk microarrays there are many significant differences identified.
As indicated in Table 4, there were many significant differences in the intensity of cell surface markers expressed on immune cells.
There were many significant differences in the girls' user characterisations associated with pack version.
Since it became apparent that there were many significant differences in performance between the young and older adults on these tasks, the middle-aged group was added to provide additional data between these two age group extremes.
When individual concepts were compared, many significant differences were found, and in all cases in which a significant difference was found, the cooperative group section had a higher proportion of students including these key concepts in their essay answers.
While there are many statistically significant differences, it can be seen from the percentages in Tables 1 and 2 that the differences are comparatively small in magnitude and that there is considerable agreement across professions about what are helpful strategies.
