Abstract: Disclosed are a class of compounds represented by formula (II), and isomers or pharmaceutically acceptable salts thereof.

Abstract: Disclosed is a series of pyrazolopyridine compounds, and application thereof in the preparation of RET kinase inhibitors for treatment. Specifically disclosed is the compound represented by formula (I), or a pharmaceutically acceptable salt thereof.

Abstract: Disclosed are a series of compounds with a nitrogen-containing spiro structure and an application thereof in the preparation of an RET kinase inhibitor. Specifically, disclosed is a compound as shown in formula (II) or a pharmaceutically acceptable salt thereof.

Abstract: Disclosed are an S-(carboxymethyl)-cysteine pharmaceutical compound (I), and a preparation method and use thereof. Also disclosed are an S-(carboxymethyl)-D-cysteine ammonium salt monohydrate, and use thereof in preparation of medicines for preventing and treating respiratory system diseases such as chronic obstructive pulmonary diseases, in particular in preparation of expectorants. The compounds can reduce airway resistance and production of oxides in rat COPD models, increase the level of antioxidants, and alleviate damage caused by the oxides and inflammatory mediators to lungs.