The DR number, Diederich Rank, refers to the highest number in Diederich's frequency listing, which you can see here: Diederich Ranking.
DR 187. Dulce domum. ~ Note: Notice the use of the neuter adjective here: the proverb does not say that a home is sweet, but that home is a sweet thing, a pleasant thing. This is also the title of the school song of the Winchester College, a boys' school in Winchester, England.
DR 187. Non omne dulce bonum. ~ Note: Here you see the neuter singular dulce again: Not every sweet thing is good. For example: CANDY. It is sweet to eat, but not good for you, alas!
DR 187. Dulce puella malum est! ~ Note: Note the nice paradox here, with the predicate wrapped around the subject: What is a girl? She is a dulce malum, a sweet evil.
DR 187. Nihil dulcius quam omnia scire. ~ Note: This is one of the sayings Erasmus included in his Adagia, 5.1.42. Note how the infinitive phrase here, omnia scire, is being used as a noun.
DR 188. Natura rerum omnium mater. ~ Note: Of course, we also speak about "Mother Nature" in English, too!
DR 188. Naturae vis maxima. ~ Note: You can understand maxima here as a true superlative ("the greatest of all") or just as an emphatic adjective: "extremely great."
DR 188. Frater est amicus quem nobis dedit Natura. ~ Note: You can also find this saying with the words: Frater est amicus quem donat natura.
DR 188. Ars vincit naturam. ~ Note: Contrary to the proverb about the power of nature (Naturae vis maxima.), this saying asserts the primacy of art (technology, craft, human ingenuity) over nature.
DR 189. Si vis scire, doce. ~ Note: Of course, every teacher knows that teaching is the best way to expand your own knowledge!
DR 189. Dies diem docet. ~ Note: We might say in English, "One day teaches another."