6．1 Text Types and Domain of Scientific Translation科学翻译的文本类型和范畴
Scientific Translation is comparatively and relatively discussed with literary translation．Different people have different views on text types．According to functionalist approaches(Reiss，1977/1989; Nord，1996/2001)，there are three main text-types: expressive texts，informative texts and operative texts．Each text-type is identified by its semantic，lexical，grammatical and stylistic features，which influence the way a text is translated and also serve as a basis for translation criticism．In the case of each text-type，these features reflect the primary function which the text serves，which should be preserved in the translation．
The major characteristics of texts of the expressive type is that they include an aesthetic component，as the author exploits the expressive and associative possibilities of the language in order to communicate his thoughts in an artistic，creative way．This means that when translating such texts the translator should try to produce an analogous aesthetic effect，as well as reproduce the semantic content of the original．The expressive text-type is exemplified to different extents by poetry，novel and biographies．(Shuttleworth ＆Cowie，2004: 56)
In the case of informative texts the primary aim is one of conveying information to the receiver．This means that a translator should concentrate on establishing semantic equivalence，and only then turn to other kinds，such as connotative or aesthetic．Similarly，a translation which is deemed to fulfill this function of reproducing in TL the informative content of SL should be judged to be successful．Reference books，business letters，official documents and academic articles all represent this text-type to varying degrees．(Shuttleworth ＆ Cowie，2004: 79)
Operative texts contain messages which are intended to persuade the receiver to undertake a certain course of action，such as buying a specific product or voting for a particular political party．In other words，in such a text both content and form are subordinated to the extralinguistic effect which the text is designed to achieve．This means that a translator＇s main aim should be produce a TT which has an equivalence persuasive force to that of the original．However，besides transmitting similar impulses to action，the translation process will also entail preserving the basic semantic nature．Political manifestos，advertisements and sermons are all examples of this type of text．(Shuttleworth ＆ Cowie，2004: 117)
In addition，Reiss uses a subsidiary text-type，multi-medial text，which supplements her three basic text typology．The multi-medial category consists of texts in which the verbal content is supplemented by elements in other media; however，all such texts will also simultaneously belong to one of the other，main text-types．Reiss argues that this texttype forms a superstructure over the other three，as the special requirements of this type take precedence over whatever basic text type a given text otherwise belongs to．Songs，comic strips，plays，and writing for radio or television are all examples of this type，and the translator of such texts will need to ensure that the translation is equally suited as the original for use in the relevant medium．(Shuttleworth ＆ Cowie，2004: 109-110)
In our view，it is acceptable to classify text-types according to text functions，which is helpful to figure out a guideline for translators and to help in the process of translation criticism．The domain for science translation contains such text-types as science and technology，social science，popular science，etc．With the development of science and technology in the present-day world，the quantities of documents dealing with science and technology such as journal papers，books，scientific reports，patent documents，proceedings are multiplying at an accelerated rate．Most of these scientific and technological texts are written in English which is the most widely used international language in the world．As a result，the so-called EST or English for Science and Technology has now become an important variety of English that has its unique stylistic characteristics．Therefore we should take account of these characteristics in the translation of English for Science and Technology．