bottom lines, bull's-eyes, centerpieces, cores, cruxes(also cruces), essences, gists, hearts, kernels, keynotes, meat and potatoes, meats, nets, nubbins, nubs, nuclei(also nucleuses), pivots, points, roots, sums

courses, directions, drifts, tenorsbodies, contents, substanceshypotheses, propositions, purports, subjects, themes, theses