A grammatical explanation in English (sorry I can't write in Chinese either):

Basically whenever an adjective follows indefinite pronouns like etwas or nichts, that adjective is taken as a noun so it is capitalized. Adjectives in German often function as nouns, and are then capitalized (ein Beschaeftigter, den Angestellen, des Auszubildenden, etc.).

However, it is still in form an adjective and thus has to take an adjective ending. Thus, it bears the strong neuter-gender ending appropriate for the case:

Ich sehe hier nichts Wichtiges. (accusative)
Finanziell fehlt es an nichts Wichtigem. (dative)
etc.

One exception to the capitalization rule is "anderes": nichts anderes, etwas anderes. This can be (barely) justified on semantic grounds, but you can read more in Duden about it.

If you break out your Old High German or Middle High German grammar book from college (everyone has one of those, right?), you'll see that *originally* the -es was a genitive ending (nichts Wichtiges cf. French rien *de* bon). Over time this genitive was reanalyzed (misanalyzed) in Modern German as a neuter adjective, whence the modern structure.

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Note added at 12 hrs 28 mins (2005-04-27 12:01:43 GMT)
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Nichts always means \"nothing.\" It would never mean \"no one\" or \"nobody.\" The translation into English of this structure is always the same: nothing + adjective:

nichts Wichtiges = nothing important
nichts Wichtigem = nothing important

Finanziell fehlt es an nichts Wichtigem = Financially, nothing important is missing.

Ich sehe darin nichts Gutes. = I see nothing good in it.

nichts Entscheidendes = nothing decisive (where entscheidend = decisive)

Note that if the word \"not\" appears in the English, then obviously \"nothing\" would become \"anything,\" as it usually does:

Ich kann nicht mit euch ohne nichts Schoeneres zu tragen.
I can*not* come with you without *anything* nicer to wear.

Translating this structure this way will always be correct. Karin\'s translation is also defensible in this case, but she has used slightly different syntax for stylistic reasons. Even so, you can see how Karin\'s solution \"nothing of importance\" is obviously synonymous with \"nothing important\" and \"nothing decisive.\" If you were learning this structure in a German class in school, however, you would be taught only the \"nothing + adjective\" meaning, and that will always be correct.

A close translation of your phrase:

When considered from a distance, the situation is much clearer. Outside of Berlin it is known that the Germans can*not* resist the Allies with *anything more decisive*. This was noted also by the author Erich Kaestner, who was in Mayrhofen in Austria on April 26, 1945. He notes in his diary:

Note that \"entgegensetzen\" is taking two objects here. The direct object, or accusative object, is \"nichts Entscheidendes\" and the indirect object, or adtive object, is \"den Alliierten.\" This means \"to resist the Allies with nothing decisive.\"